-- -- $Id: README 279 2008-11-03 23:51:30Z jcw $ -- $Revision: 279 $ -- $Author: jcw $ -- $Date: 2008-11-03 18:51:30 -0500 (Mon, 03 Nov 2008) $ -- $HeadURL: http://tinymicros.com/svn_public/arm/lpc2148_demo/trunk/README $ -- J.C. Wren 2008/11/03 jcwren@jcwren.com The most recent version of this package may be found at http://jcwren.com/arm PayPal donations cheerfully accepted at jcwren@jcwren.com. No obligation what-so-ever, but any amount is appreciated. Received funds go towards purchasing other evaluation platforms, so I can create other demo code packages. I'm changing the format of how updates are documented. Rather than including it in the body of the text, they will be appended to the front, with a date. 2008/11/03, version 1.40: Renamed the lpc210x.h file to lpc214x.h, since it's fairly LPC214x specific. Added uIP TCP/IP stack. Requires a Microchip ENC28J60 connected to the SPI0 port. Interrupt is on EINT3 (pin 34). This requires that the RS1/UEXT jumper be placed in the UEXT position, and also means that UART1 cannot be used (for the demo code, this is normally setup for the GPS). See the included 'docs/inj28j60.png' and 'docs/enc28j60.png' files. The in28J60 module was obtained from The Microcontroller Shop (http://microcontrollershop.com) for about $30 USD. See the 'uip/README' file for details. uIP is started with 'uip start'. By default, DHCP is enabled. This can be disabled with 'uip dhcp off', and setting a static IP address set with 'uip ip 192.168.1.1'. The gateway can be set with 'uip gw 192.168.1.254', and the netmask set with 'uip nm 255.255.255.0'. 'uip ip', 'uip gw' and 'uip nm' with no arguments prints the current values. Note the default static IP address is 0.0.0.0, as is the gateway and netmask. You need to reset these after each reset of the board (there is no provision for storing these in FLASH or uninitialized RAM, yet). There is a reasonable about of checking on the IP address syntax, but all possible errors may not be covered. The MAC address can be set with 'uip mac 00:01:02:03:04:05', where each digit pair is a hex value. If not overridden, the default MAC address of 00:bd:3b:33:05:71 is used. This sets the MAC address in both the ENC28J60 and the uIP stack. 'uip mac' with no parameter prints the current MAC address. 'uip start' starts the uIP stack, web server and telnet server. I considered having the webserver serve files from the CF card, but decided against that the extra step of having a correctly formatted CF card was not necessary. uIP can be enabled or disabled in the top-level Makefile via the CFG_UIP option. The telnet and httpd servers, along with DHCP, can also be selectively enabled or disabled in the Makefile with the CFG_TELNETD, CFG_HTTPD and CFG_DHCP options. 'uip sntp ' will make 10 requests 10 seconds apart to a SNTP server. If the time is returned, the RTC will automatically be set (time is UTC). This does not currently implement the two-step process to compensate for network delays. Using a nearby time server is recommended. If time server is returned has been returned in the DHCP request, time may be set with 'uip sntp set'. Time offset will be applied if set via 'uip to' or if returned in the DHCP request. Note that the telnet server runs in parallel with the serial or USB console, so any input or output on one will be seen on the other. KNOWN BUG: If the USB console does not have a session open, the telnet session will hang. The USB code needs some way to check if the pipe is not open, and skip the write if is not. I haven't figured out how to do this yet :) Added a few more #defines for the SPI modules to the lpc214x.h file, along with additional GPIO bit combinations. The mmc/spi.c file has been renamed to mmc/ssp.c. The mmc/spi.h file has been renamed to mmc/ssp.h. All functions that previously started with 'spi' have been renamed to 'ssp'. Pins that drive the LEDs are now configured in leds/leds.c in ledInit(), rather than in cpu/cpu.c. UART pins are now assigned in uart/uart.c initialization code rather than in cpu/cpu.c. The UART code has been factored out into completely separate files, to make it easier to delete support for a UART when not needed. Previously, all the UART code was in uart/uart.c and uart/uartISR.c, and a switch() statement was used to specify which UART was to be operated on. They have now been broken into separate files, and named accordingly. The external interrupts (EINT) code has been factored out into completely separate files. Here again, that should make deleting unwanted code for other projects easier. Also added EINT1 (unused for anything, could be used to have the BSL switch generate an interrupt), and EINT3 (for uIP/ENC28J60 support). Add *.c, *.h, *.s and Makefiles have subversion tags Added various GCC warning suppressions in the uip Makefiles to keep GCC from complaining about difference in signedness, type-punned pointers, casting alignment, etc. This is not the way to fix the problem. uIP should be fixed directly, but I was generally trying to avoid altering the original source as much as possible. Pin assignment in peripherals modules rearranged to enable peripheral after pin assignment. Although not clear what chapter 7.3 means by "peripherals should be connected to the appropriate pins prior to being activated", I take that to mean prior to being enabled in the SCB_PCONP register. Pin assignments now correctly mask bits beforing OR'ing in pin function (this didn't un-break anything, but it's the more correct method. See eints/eints0.c as an example). LED, GPS and sensors task can now be selectively stopped and restarted. LCD support is now conditionally defined in the top-level Makefile (it is enabled by default) Rewrote GPS parser to get rid of scanf(), saved 22K of code space, and reduced the stack requirements for the GPS task from 2K to 512 bytes. 2008/10/04, version 1.30: Updated FreeRTOS to version 5.0.4 The I/O ports are now configured and used in fast I/O port mode, rather than legacy slow-poke mode. Most people in the real world have no need of the slower legacy mode. Added 'misc ports' command to display the _PIN, _DIR and _MASK registers of port 0 and 1. Added LCD example. There are two files in the lcd directory, lcd_4bit.c and lcd_8bit.c. The lcd_4bit is suitable for the Olimex LPC-P2148 board (which this demo code is targeted for). The lcd_8bit.c file is targeted for an LCD that has a full 8-bit interface. The 8-bit code was extracted from a previous project and is untested, but SHOULD either work as-is (adjusting for the port pin assignments, of course), or be very close. The LCD is handled in it's own task, started and stopped with 'lcd start' and 'lcd stop'. This shows dynamic task creation and destruction, and means the LCD task won't automatically start for users without LCDs connected. Use 'lcd msg ""' to display a message, 'lcd clear' to clear screen, and 'lcd gotoxy <0..1> <0..19>' to position the cursor for writing. Added PWM example. Unfortunately, this will require an oscilloscope or logic analyzer to be able to see the results of it. At reset, PWM5 is set up for a 20Khz period, and a duty cycle of 50%. The frequency can be varied with the 'pwm freq' command (between 1 and 48000000Hz), and the duty cycle can be varied with the 'pwm duty' command (between 0 and 100%). This code was extracted from another project that used it to control a bias circuit for LCD contrast. Added an example of using the timer 1 match registers. In a previous release, I had made the statement that how Olimex drove the speaker was flawed. Thanks to some code contributed by Dave Madden, it turns out that using timer 1 and the match registers, tones between 60 and 20,000 Hertz can be fairly easily generated. Either Olimex saw this early on, or they just got lucky ('beep off', 'beep on <60..20000>'). Using the previous code as the base, the demo code now plays 'Mary Had A Little Lamb' on the squeaker ('beep mhall'), and a really lousy version of 'Smoke On The Water' ('beep smotw'). I don't read guitar tablature, and I had a heck of time trying to find the notes and duration for the opening riff. Interrupt vectors are now in RAM by default. When the system starts, they are initially in flash. The FIQ interrupt (which does nothing but count FIQ events) gets copied to RAM, as do the interrupt vectors. This allows the FIQ to run as fast as possible. Note that if 'fiq on' is running, and the beep commands are used, the FIQ interrupt counter will stop running, as the beep code also uses timer 1. All the file related command have been moved to the 'file' submenu in the monitor. This makes the top level commands cleaner and more topical to the section they serve. Use 'file init' if you change the card without rebooting the system. Remember to use 'file mount' to mount a MMC/SD card that's installed at boot or after 'file init'. Added a prompt to indicate the system is ready for commands ("Demo>"). Thanks to Dave Madden (again) for that code fragment. Improved USB performance, thanks to code from Jan Topolski. This fixes the issue where the system performs very poorly under Windows when connected via USB. Windows apparently is sending a constant stream of NAKs, with each NAK generating an interrupt. The effect of this could be seen when running the MMC/SD card performance tests. When connected to a Windows box, the performance was about 10% of that when connected to a Linux box. Jan also optimized the code that checks for the USB interrupt source. In the original code, all 32 possible interrupts were checked each time in a loop. The modified code aborts the loop early when it sees that all interrupts have been handled. The MMC/SD code should be more tolerant of various cards at the SPI level. David Johnson contributed an improved SPI I/O routine and reports that Sandisk cards now work for him. Note that only cards which have 512 byte sectors are supported. The MMC/SD code now checks the card present (P1.25) and write protect (P1.24) switches on the MMC/SD card socket. File operations will fail if the card is not present, or an attempt to write to a protected card is made. The MMC and SPI drivers have been factored out of the FatFS code so they can be shared with the USB mass storage code (usbmass). This should also make it easier to port to other LPC2xxx family parts, such as the LPC2468, which has an improved MMC/SD interface. The lpc210x.h header file has been updated with addition definitions, primarily in the fast GPIO and the PWM modules. Removed some unused files from the I2C code. Those files should have been deleted prior to the final release package. Added -Wno-strict-aliasing to the FreeRTOS/Makefile to eliminate some warnings. Also added -Wno-cast-align to FreeRTOS/Makefile and usbmass/Makefile to eliminate some casting warnings. The usbmass storage driver seems to work, although it is abysmally slow. It's very inadvisable to use the 'file' commands while the MMC/SD card is mounted under Windows (and probably Linux), due to common buffers. The driver is enabled in top-level Makefile, with the -D CFG_USB_MSC option. Please note that the terminal window of Flash Magic is squirrely. I thought there was a bug when copying large files to the console ('file cp '), and this sent me on a short wild goose chase. Garbage was being emitted after roughly 16K bytes. Turns out that the Flash Magic terminal window is just plain slow, and it's getting stupid when it can no longer keep up. Also, 'file cpcon ' expects control-D to stop copying the file, and the terminal window does not pass control characters. ProComm (and others, but never, ever, EVER HyperTerm) is a much better choice for straight serial work. 2007/07/22, version 1.20: Added interrupt driven I2C master transmit and receive code. I'm pretty confident that all the cases are handled correctly, but I don't have any way to introduce certain errors for testing. There are now two files in the ./i2c directory, "i2cInt.c" and "i2cPolled.c". Edit the ./i2c/Makefile to select interrupt drive or polled I2C handling. There is some support for debugging I2C the interrupt drive routines. As interrupts occur, the various state changes are recorded, and the 'i2c dump' command will display them. This is disabled by default, but can be enabled by editing the ./i2c/i2cInt.c file and defining I2C_DEBUG. Added raw I2C support. The 'i2c' commands allow directly reading and writing an I2C device (as opposed to using the LM75 wrapper for LM75's, or the EEPROM wrapper for EEPROMs). See 'i2c help' for a list of commands. Note that when reading from an I2C device via the raw commands, a maximum of 16 bytes may be read or written. If you need more, change the buffer sizes in the appropriate commands in ./monitor/monitor.c, and also the maximum number of arguments in the command dispatch table (commandListI2C). Added EEPROM support. The 'ee' subset of commands allow reading and writing of a 24Cxxx series type EEPROM. The code is currently targeted at an Atmel 24C1024 128x8 part (I had some laying around). It should be pretty easy to rework them for any smaller part. See 'ee help' for a list of supported commands. Fixed the LM75 support to allow writing the config, TOS and THYST registers. The previous versions allowed reading the registers, but I forgot to write code to allow changing them. Oops. Moved 'date' and 'setdate' commands into the 'rtc' sub-menu as 'get' and 'set', respectively. Added 'alarm' command that allows setting an alarm date/time, or disabling it. When an alarm fires, 'ALARM -- YYYY/MM/DD HH:MM:SS' is printed to the console. Also added 'periodic', which when enabled, prints 'PERIODIC -- YYYY/MM/DD HH:MM:SS' to the console at the top of every minute. The RTC also demonstrates using the default vector address functionality of the non-vectored IRQs in the VIC (alternatively, by un-defining RTC_NONVECTOREDIRQ in the ./rtc/rtc.h file, a regular vectored IRQ can be used). Note on the RTC alarm and periodic output: It's really gross. Console input is handled by a libc read() call. This is a blocking call, implemented by doing a FreeRTOS xQueueReceive in the console device code (UART 0, UART 1, or USB). So the only way to get the read() to return so the CCI can output the message is to reserve the special characters 0xfe and 0xff (something a user can usually never type). When the CCI getline routine sees either of those characters, it immediately returns. These characters are then checked for by the CCI command parser, and either an alarm or periodic message output. If the user is in the process of typing in a command, the input will be lost. Without totally rewriting the CCI into a queue based message passing architecture, I couldn't find a more elegant way to handle this. So basically, the RTC interrupt sends a 0xfe or 0xff into the input buffer for the console device, which then returns the character, which is then processed by the CCI code. Changed the 'task' command to a 'mem' sub-command. Added the 'map' command, which shows how memory is allocated. Overview: The .txt section contains the program code, the initialization values for static data in RAM (statements like 'static int i = 172;'), and the glue section (I believe this is where ARM/THUMB inter-networking code is placed). The .data section is the area of RAM that gets initialized from the constants in FLASH at startup (so that i == 172). The .bss section is all static data that is zero length (statements like 'static int foo [12]'). The 'map' command prints out the starting and ending address of each area (size calulation is left to the user). Also included is the starting and ending addresses for the various stacks (undefined, abort, FIQ, IRQ, service), the start of heap, and the current heap end. The scheduler executes in supervisor mode, tasks execute in system mode. Added FIQ demo. Timer 1 is set up to interrupt at 8hz (8 times a second, or every 125 milliseconds), and is configured as a fast interrupt. The interrupt handler does nothing more than increment a counter. The 'fiq on' command will enable the timer, 'fiq off' will disable it, 'fiq count' will print the counter value, and 'fiq clear' will reset the counter to 0. As long as the FIQ is enabled, it should be merrily counting along. NOTE: the actual FIQ vector is in ./boot.s. Also in this file is the FIQ stack size. I've set it to 32 bytes (8 words). This was derived empirically by examining the lpc2148.lst file, and seeing how many registers were pushed by the fiqISR code. Only 3 registers are pushed, so 8 words was deemed enough space. An interrupt that actually does anything substantial will require more stack space, and the FIQ_STACK_SIZE should be adjusted accordingly. The FIQ in the CPSR is enabled by FreeRTOS when it starts the scheduler, just like the IRQ. The stacks have been tuned down pretty small to allow a larger heap area. Many boot.s files allocate 1K for the supervisor stack, and another 1K for the IRQ stack. I've tried to exercise all the functions in the demo to get a feel for stack usage, and both of those stacks have been tuned down to 256 bytes each. There shouldn't be any issue with using a lot of stack in any code prior to the call to vTaskStartScheduler(), since the supervisor stack will overflow into system/user stack space. Once tasks are running, they have their own private stack spaces inside the FreeRTOS allocated memory. If the interrupt routines are modified to use more dynamic space, then the interrupt stack may need to be increased. So far, I've seen less than 50% utilization. The FIQ stack is very small, as it does nothing more than increment a counter. More complex FIQ routines will need more space. Fixed problem with CCI 'mv' command failing. Default compiliation options for newlib for ARM don't define HAVE_RENAME, so the newlib rename() was trying to do the link/unlink method of rename a file. FatFS (and FAT file systems) don't support links, so this was always failing, since link() returns -1. Provided our own rename() in newlib/syscalls.c to override the newlib rename(). Added a data abort, prefetch abort and undefined instruction handler. The abort handler works by saving the state of the CPU to a block of memory, then enabling the watchdog to force a reset. This method was used instead of printing directly to the serial port, as some people are using the USB as the console port, and there's no gaurantee that the system is still stable enough for USB to work. So instead, the state is saved, the reset is forced, and the user can then use the 'abort' set of commands to examine the system state. The 'regs' command will display the registers at the time of the abort, and print the opcode of the instruction that failed (except for prefetch abort). The 'clear' command sets the memory used by the abort handler to 0's. The 'dirty' command sets the sigil used to indicate if the abort memory contains valid data. 'dabort', 'pabort' and 'undef' force each of the types of aborts. To try it, start the system, type 'abort clear', then 'abort regs'. All registers should be 0. Now type 'abort dabort'. This forces an access to location 0x40008000, which does not exist. After the LPC2148 has reset, type 'abort regs'. Examine the PC value, open the lpc2148.lst file in an editor, and search for that address. You should find that the abort occurred in the monitorAbortDabort code, at the 'ldrb' instruction. Note that if the PC is showing somewhere in the boot.s code area, it's likely a double abort is occuring. Most likely the stack pointer was already corrupted at the time of the abort, and when the stack is being copied, it's reading from memory that will cause a data abort. After an abort, you'll want to do a 'wdt clear' to clear the WDMOD.WDTOF flag, otherwise you'll be unable to re-enter ISP mode without a power cycle. Added 'misc' menu, which right now consists of the 'sizeof' command. This displays the size of the common C data types (just in case you weren't sure a void * is 4 byes). I'll add others here later, like when FreeRTOS starts exposing structure sizes in a future release. Updated FreeRTOS to version 4.4.0 CURRENTLY BROKE, WAITING FOR JTAG DONGLE (feel free to submit a fix). Added USB mass storage capability. If CFG_USB_MSC is defined in the Makefile, USB serial support will be disabled, and mass storage enabled. This allows the MMC/SD card to be mounted like a disk drive. DANGER! The CCI commands for file management remain enabled. This means you can create a file on the Windows (or Linux) mounted device, and see the changes from the CCI. HOWEVER: The SPI routines that read/write the MMC/SD card are not thread-safe, so a USB request to read/write the disk can interrupt a CCI command. It's crazy dangerous to actually use the CCI file commands while the MMC/SD card is mounted under Windows or Linux. What you can do is mount the MMC/SD card, copy files to/from it, unmount it, then use the CCI commands to see that things really changed. A later revision of the demo package will likely at least protect the SPI I/O from being interrupted (although this defeats the 'Real' in RTOS to do so). Overview: This package demonstrates using LPCUSB and FatFS under FreeRTOS on the Olimex LPC2148 board, using GCC and newlib. Examples include FreeRTOS queues and semaphores, LPC2148 analog to digital converters (ADCs), external interrupts, the real-time clock (RTC), general purpose IO (GPIO), serial ports (UARTs), and USB. Also included is a newlib syscalls.c that almost completely implements all syscalls.c functions. The package (as built, .hex file included) presents the USB port as a virtual comm port. The virtualized port is used to talk to the console command interpeter (CCI), that allows various functions to be exercised. Alternatively, the package can re-compiled to use UART0 as the console port. If a GPS with NMEA output at 4800 baud is connected to UART1, one of the tasks will parse the NMEA input stream, and display a position report. In addition, the RTC may be set from the GPS time/date. FatFS support is included, and the CCI has several Unix-y commands to manipulate files (mkfs, df, ls, mkdir, rmdir, rm, mv, cp, chmod, and sync). There is also a command that allows through-put testing on the MMC/SD card. This package exists because I wanted to familiarize myself with the LPC2148, FreeRTOS, FatFS and LPCUSB for a personal project, using GCC and newlib (who can afford those commercial packages? Not I). By slightly modifying the resulting framework, I was able to produce a package that others may possibly find useful. Software tools: The package compiles using the arm-elf GCC package. Gentoo users can install this by emerging the 'crossdev' package, then 'crossdev -t arm-elf'. Once the arm-elf verison of GCC is installed, the package can be rebuilt with 'make'. To program the board, the Philips LPC2000 Flash Utility v2.2.3 Windows tool was used. There are Linux based tools for programming the LPC21xx parts, any of which support the LPC2148 should be suitable. It may be normal, but I couldn't get the board to program at speeds other than 19200 and 38400. ProComm was used to talk to the console port on UART0, and HyperTerm to talk to the console port when using USB (Don't get me started on how crappy HyperTerm is. I *DESPISE* this abortion, and figure that Hilgraeve must have pictures of Gates with a goat or something. We can argue about MS quality all day long, but HT has all the "quality" of a 6 year olds first programming project in QBASIC. The only reason it was used was because ProComm can't talk to COM18, which is what the virtual serial port appears as). If using the USB virtual comm port under Windows, the 'usbser.sys' and 'usbser.inf' files may be needed. Often, these files are already on the drive somewhere, and Start->Search->Files can be used to located them. If not present, they are included in the ./Windows directory in the package. Under Linux, 'minicom' should be able to talk to both the serial port and the virtual comm port the USB port appears as. Bertrik's wiki, located at "http://wiki.sikken.nl/index.php?title=LPCUSB", has a note about using LPCUSB under Linux. The default baud rate for UART0 is 115200. The baud rate selected for the USB virtual comm port is irrelevant, and may be any speed. Rebuilding it: Simply typing 'make' should build the entire package. The FreeRTOS modules will emit several warnings about type punned references, which can (safely?) be ignored. If you wish to use UART0 for the console port, edit ./monitor/monitor.c, jump to near line 938, and change the "#if 1' to '#if 0', then recompile. If you wish to change the baud rates for UART0 or UART1, edit ./main.c, jump to near line 62, and change the rates. Any standard baud rate should produce usable results. 'make clean' will clean the project, removing the ./*.hex, ./*.lst, ./*.map, ./*.elf files, and ./common/common.a, along with all *.o and .depend files in any sub-directories. 'make tags' will rebuild the ctags file for 'vi' (and no doubt emacs, if you're one of "them"). Hardware (required and optional): Olimex LPC-P2148 board (required) USB cable (optional) Serial cable (optional) GPS with NMEA output and serial cable (optional) Using it (Windows): For the purposes of these instructions, it will be assumed that COM1 is the serial port on the host PC, a USB cable is connected to the LPC-P2148 board and the PC, and that the Philips LPC2000 Flash Utility V2.2.3 will be used for programming. Please note that Windows 2000 was used, and that dialogs for Windows XP are probably slightly different. If you're using Vista, I'm surprised it can stay up long enough for you to read this document... Connect the RS232_0/ICSP DB-9 on the LPC-P2148 board to the comm port on the PC, using a straight-thru serial cable. Set both the ICSP slide switches (located near the RS232_0/ICSP DB-9 connector) to the 'on' position (towards the DB-9 connector), then press the reset button (located next to the ICSP switches). Configure the Philips utility for COM1, 38400 baud. Click the 'Read Device ID' button. LPC2148 should appear in the 'Device' text field. Note that the device ID has to be read to set the value, as there's a nasty bug in the utility that prevents selecting it from the drop down list. Click the "..." button in the 'Flash Programming' block, then locate and select the 'lpc2148.hex' file, followed by clicking the 'Upload to Flash' button. At this point, the flash image should start being programmed. When it completes, set the two ISCP slide switches to 'off', and press the reset button. The 'LED1' LED should start flashing. If Windows already does not already have the 'usbser.sys' driver installed, a dialog will appear regarding the discovery of new hardware. (I don't remember how the dialog goes, so you'll have to infer your way through this process). When prompted for the driver, navigate to the ./Windows directory, and select 'usbser.inf'. This should install the driver for the virtual comm port that will support the USB port. Right-click on the 'My Computer' icon on the Windows desktop, select Properties, then the Hardware tab, followed by 'Device Manager'. Click the '+' on the 'Ports (COM & LPT), and there should be an entry for "USB CDC serial port emulation (COMxx)" (where 'xx' will be a number). Note the COM port for use with HyperTerm (see previous rant). Start HyperTerm (Start->Programs->Accessories->Communications->HyperTerm) (see previous rant). When the dialog appears, type a name for the connection (The COMxx name is a good choice). Click the drop-down box under 'Connect using'. Select the COMxx port name from the drop-down list. Click 'OK', followed by File->Save. Now click the third icon from the left, which looks like a telephone with the handset on the hook. If all went well, typing 'help' should show a list of commands supported by the CCI. If so, congratulations! You can now play with various commands. If not, there's not much advice that can be offered at this point. Baldur Gislason informed me that the Philips Flash Utility has been replaced by by Flash Magic (http://www.flashmagictool.com). I gave this a try, and it worked well enough. It's a nicer interface, but it seems a tad slower. Rather than go into detail how to use it, I'll just say that I set the devce to LPC2148, interface to 'None (ISP)', the oscillator frequency to 12.00000, and checked the 'Erase blocks used by Hex File', and it just worked. Using it (Linux): Eeek! This needs to be written. (Richard T. Stofer says that Debian plays nicely with the LPCUSB code. with the virtualized comm port appearing as ACM0. 'minicom' can talk to this port). Hardware thingies: The two pushy buttons on the LPC-P2148 board (B1 and B2) enable and disable LED2. Pressing B1 should light LED2, pressing B2 should extinguish it. These buttons are connected to the EINT2 and EINT0 lines, respectively. The associated code demonstrates handling an external interrupt, and toggling an I/O pin in the interrupt service routine (ISR). The potentiometer, AN_TR, is connected to ADC0, channel 3. The 'sensors' task checks the value every 100 milliseconds. The software divides the pot into 4 zones, each covering about 1/4 of the range the pot may be rotated. When the pot is fully counter-clockwise, LED1 will be on for 200 milliseconds and off for 800. When the pot is moved to the 2nd zone, the on/off times become 400ms/600ms. The 3rd zone has on/off times of 600ms/400ms, and fully clockwise is 800ms on, 200ms off. LED1 is controlled by the LED task. This is a lower priority task. Each time a single on/off cycle has completed, it's message queue is checked to see if the blink ratio times should be changed due to the AN_TR pot changing zones. LED2 is controlled by the B1 and B2 pushy buttons, as mentioned above. The DAC output on the AOUT pin changes every 100 milliseconds by 1/64 of the range of the DAC (0.0515625 volts). The generates a sine wave with a period of 12.8 seconds, or 0.078125 Hertz. Hang a 'scope or DVM on the AOUT pin to see the change. The I2C routines are setup to talk to a LM75 temperature sensor. These can often be found on old PC motherboards, or as samples from National. The I2C demo code is a simple polled approach, and does not take advantage of either interrupts or the I2C state machine. The 'lm75' CCI command allows reading and writing of the configuration, THYST and TOS registers, and reading of the temperature register. The 'lm75 mode' command determines if the registers are read using an I2C repeated start sequence instead of an I2C stop then I2C start. Repeated starts are faster, and allow for holding the I2C bus in a multi-master environment. The default is repeated starts (mode 0). There is one potential spot for the code to hang. If the I2C bus fails to release SCL (if the I2C device is powered down, perhaps), it will hang waiting for the status interrupt bit to change. Any hard while loops should be wrapped in a counter or timer check. Demo now includes watchdog timer example. 'wdt test' enables the watchdog. If no command is typed for 10 seconds, the system will reset. 'wdt status' can be used to examine the current watchdog state and the RSIR register (which allows determination of why a reset occurred). Use 'wdt clear' to clear the RSIR status. Sort of hardware thingies: The SWI demo code is taken from several different projects, and culled down into something I felt was more readable, and better for explanations. The CCI 'swi' commands allow setting the state of, turning on, turning off and toggling LED2. The commands starting with 'a' use the assembly interface (assembly sequences are used to affect LED2), whereas the commands starting with 'c' manage LED2 in C. Note that the pushy-buttons also toggle LED2, so there can be some interaction. CCI commands: If you're a Linux user, most of the file commands are fairly self explanatory. If you're not a Linux user, you should be, because it's better on our side of the fence. The file commands require that a MMC/SD card be installed in the MMC/SD slot. BEFORE USING THE FILE COMMANDS, USE THE 'mount' COMMAND TO MOUNT THE MMC/SD CARD. Note that the first partition on the MMC/SD card will be mounted, and this is the only one supported. It must be a FAT12, FAT16 or FAT32 partition. If the MMC/SD card is not formatted with a FAT12/FAT16/FAT32 file system, you can use the 'mkfs' command to create it. If anything already exists on the card, 'mkfs' will wipe it out. Note that while a fairly good success rate has been obtained with the cards on hand, one Sandisk 64MB MMC card did not work. Not sure why, but the MMC drivers are probably not handling something quite right. 'cpcon ' allows a text file to be created from the CCI. Enter text until you're bored, then type ctrl-d save and exit. Note that whatever characters are typed are saved into the file verbatim. This means that characters like backspace are actually put into the file (feel free to improve that code...) Before creating any files, you may wish to set the system date, so that files are date/time stamped properly. If a GPS with NMEA output is connected to RS232_1, you can use the 'gps' command to verify the serial connection, that NMEA data is being parsed, and that the GPS has acquired (required for the date/time to be set). If you have no GPS attached, you may enter the date and time as parameters. 'settime 2007/07/08 22:51:25' will set the date and time to July 8th, 10:51pm and 25 seconds. No timezone info is applied, so date/times acquired from the GPS are UTC. Date/times set manually may be set to local time or UTC (or something completely random, if you're into that). The 'thruput' command allows measuring MMC/SD read and write performance. Eight file sizes are used: 1K, 8K, 16K, 64K, 128K, 512K, 1MB, and 2MB. A temporary file is created on the MMC/SD card. Measurements can be done one of four ways: 'noints' (fastest, but disables all tasking), 'normal' (CCI task priority is not changed, no tasks are suspended), 'suspendall' (all tasks are suspended, no context switches made, but 10ms interrupts still runs), and 'high' (CCI task is elevated to highest priority for duration of test). Oddly, writes are faster than reads when not using the 'noints' mode. I have not yet researched why. Leaving interrupts enabled *seriously* impacts the file system performance, nominally by a factor of 20. Richard T. Stofer noticed that this slow down only appears when using the 'usbser.sys' drivers under Windows. When using the Linux ACM drivers, or when using UART0 as the console port with the USB cable disconnected, this problem does not occur. We can only assume that the Windows driver sends lots of (needless) packets (yet another reason to switch to Linux!) The 'date' command will report the current date/time from the RTC. If you have an external 3V battery plugged into the BAT connector, the RTC will preserve it's values across power-downs. Regardless of the battery presence, date/time will be preserved across resets (as long as power is not removed). The 'sensors' commands reports very little useful information. The sensors task executes every 100ms, and samples the ADC connected to the AN_TR potentiometer. Every time the task runs, the sensors counter is increment by one. If the AN_TR pot is adjusted far enough to change the zone, the ADC changed value will increment. See the section above on the pot. The associated code demonstrates running a high priority task with a constant execution frequency, sampling an ADC, and sending a message to another task. The 'mem' command displays the various tasks running, and the amount of unused stack available to each task, along with the task priority and such. The associated code demonstrates the 'vTaskList' RTOS call. Note that in a 'real' system, leaving the task trace code enabled (configUSE_TRACE_FACILITY) imposes a slight penalty on context switches, which may be undesirable. The 'iap' commands allow experimenting with the In-Application Programming (IAP) code. The demo code demonstrates preparing, erasing, writing, blank checking, and retrieving processor ID and boot loader version numbers. IAP deals with primarily with sectors. In the LPC2148 (which has 512K of flash), there are 4K and 32K sectors. The CCI will not allow selecting sectors that are used for code. The 'fss' command will find a safe sector to use with the 'iap' commands. Once a safe sector is known, you can erase and fill this sector. The blank checking will work on any valid sector (there are 27 in the LPC2148). The IAP_COPYRAMTOFLASH (writing to flash) is demonstrated by the fill command. Whatever size the sector selected is, the 'fill' command will fill the entire contents with the supplied byte value. The 'md' command can be used to dump the sector contents to see the effects of 'erase' and 'fill'. The 'stoa' command is used to convert a sector number to an address for 'md'. It is strongly recommended that you become familiar with the section on IAP in the LPC2148 datasheet before using these commands. The IAP prepare and compare functions are not CCI accessible. These are handled internally by the erase and fill code. MMC/SD notes: As mentioned above, I have a Sandisk 64MB MMC card that the MMC drivers can't seem to recognize. I have 4 other cards that work fine, one of which is an MMC, the other three which are SD. I'd like to resolve this issue. During the 'thruput' test, when interrupts are left enabled, I have on rare occasions seen a read or write error occur. I believe this is because a context switch is taking place during some time critical code. Ideally, interrupts would be disabled. However, disabling interrupts makes an RTOS merely an OS. The 'real-time' part means predictable response to interrupts, and the executing time-critical tasks on-time. In this code, the MMC/SD code is non-reentrant (only one task may read/write the card), and not time critical. If multiple tasks have to write to disk, this would currently have to be handled by creating a task that communicates through queues to other tasks, and manages the MMC/SD card. Note that if a GPS is connected, a message that a NMEA checksum could not be found may occasionally appear. While the actual test is being run, the GPS task is not processing messages, and the serial buffer overruns. When the task is allowed to run again (between tests), partial NMEA messages that cannot be parsed may be present, resulting in the error message. GCC notes: This code was compiled with -O3. This results in code that's about 16K larger than -Os, but has a measurable impact on the MMC/SD card throughput (not large, but it can be seen). I went with -O3 because with 512K of FLASH, and 144K or so used, there's plenty of room. I'm not sure what the compiliation options for newlib are. 'crossdev' compiled those, and I suspect it was with -Os, since embedded systems generally tend to consider size over speed. GCC is an amazing package. I'm used to running into compiler issues with many of the micros that I work with (SCCS, Microchips C18, etc). It's so nice to have a compiler that produces code without problems, and doesn't have idiot front-ends that can't even get the sign on an enum correct (at least Microchip got it right for the dsPIC and PIC24 parts, which used GCC. C18... Don't go there...) There's a trick to writing Makefiles, and I don't have it. It's an arcane art, and involves the slaughtering of goats, black candles, and full moons. The Makefiles I did write are very basic, and use recursion ('Recursive make considered harmful!'. Foo on that. Worked for me). I tried a couple of approaches, and either everything built anyway, or nothing built at all. To make the linking work, as files are compiled, they're dumped in to ./common/common.a, and main.c is linked against that. So far, the expected bite on the butt for doing it this way has not happened. It would be really neat to have Makefiles done right. Alas, I don't know how to do it right. So if the common.a approach looks really ugly to you, that means you probably know how to write Makefiles that handle sub-directories correctly, and you can tell me how it should be done :) (With examples!) Notes on newlib: I wasn't happy with the newlib syscalls.c that was included in the original LPC2148 port. I more or less completely rewrote this, with the exception of _sbrk(). _open() can open the serial ports, USB port, and FatFS files. All supporting functions except _fstat() work (see FatFS complaint at bottom). Newlibs method of converting a file descriptor (as returned by _open()) to a slot (which points to assorted info for that fd) uses a loop. As this is done on EVERY read and write call, unnecessary overhead is added. I fixed the find_slot() code to cache the last fd, and if it's the same on a subsequent call, the search is skipped. _open() is VERY suspect, in that remapping of FatFS f_open flags don't correspond cleanly to Unix's open() call. I handle the four common cases correctly, but lesser used ones may result in a EINVAL errno on open. Opening FatFS files is expensive, RAM space-wise. Each open file uses a FatFS FIL structure which contains a 512 byte buffer, plus some additional space. With 32K on a LPC2148, and 20K being used for the FreeRTOS heap, that leaves 12K that has to be used for the stack, heap, printf(), etc. Don't go wild opening files, and be sure to close unused files to free the space. Use open() instead of fopen() whenever possible, as the FILE structure has it's own set of buffers. There may be a way to figure out how much heap and stack have been used under newlib. If there is, I haven't figured it out yet. I'd really like to be able to make a newlib or system call that returns total space available, heap used and stack used. Since stdout and stderr point to same place, it's wise to close stderr and set stderr to stdout. Only functions like assert() use stderr, so intermixing stderr and stdout shouldn't be a problem. Especially since there's no redirection of I/O... Header file for LPC2148 (lpc210x.h): The original LPC2148 header file was very lacking. Not only were individual bit fields generally not defined, major peripherials weren't defined. As a result, FreeRTOS, LPCUSB, FatFS and newlib all used local defines. Worse, some of these were simply "SOMEREG = (1<<31)". Great. What does bit 31 do? Personally, I feel the best way is to define structures AND #defines. It's good that a structure has an element called 'CLK', but setting CLK to 0 doesn't give a hint as to what clock mode is being set. A #define for XXX_YYY_CLK_BIPHASE, then saying XXX_YYY_bits.ClkMode=XXX_YYY_CLK_BIPHASE is a lot clearer. I defined a mess of #defines, with the majority matching the names in the datasheet. There were few that become triplely redundant, such as WD_WDFEED_WDFEED1. This was reduced to WD_FEED_FEED1. The characters prior to the first underscore define the module, with the next set the defining the register name. Subsequent fields define the bit field name, and then possible variations. What I don't like about using #defines to define the registers is that the programmer needs to know if the bits being affected need to be AND'ed or OR'ed. Structures neatly solve this problem, but defining all the structures takes a lot of work (yea, IAR has already done that, but it's not legal to just swipe their nice headers). With one exception I'm aware of (in the TODO section), I rewrote all the code that sets registers to use the values in the lpc210x.h file. While I doubt it makes the code more portable (will NXP change block addresses, but leave bits the same? Probably not), it does make it more readable. One of the last major areas to be completed is to pull the USB protocol engine #defines into lpc210x.h. These are currently defined in one of the USB header files, and have poor name scoping (does "ACK_STAT" tell you what module or register it applies to? No.) Software notes: All copyrights are by their respective authors. FreeRTOS is by Richard Barry. LPCUSB is by Bertrik Sikken. FatFS is by ChaN, with sections by Joel Winarske. Other sections of code may have come from the intarweb, and have respective copyrights, indicated or not. Any code that I personally authored is free for public consumption, unemcumbered by any copyrights, etc (that crap is just too confusing. BSD? LPGL? GPL3? Who the hell knows...) I've re-formatted a good deal of code in LPCUSB and FatFS. Some portions were re-written, others simply re-formatted to my coding style (which I jokingly refer to as JC1). I have occasionally whacked comment blocks that I didn't really think indicated what the code did, or was redundant. I probably whacked some text with copyrights in the process. This in no way reflects an attempt to claim the work as my own, or to otherwise dishonor the original authors. As Isaac Newton (more or less) said, "If I have seen a little further it is by standing on the shoulders of Giants." Without the work of these most excellent people, this code would not exist. Most of the reason for my re-formatting is my way of understanding the code, going through it section by section. It's good because I have a better understanding of it, worse because it makes drop-in replacement with updates from the authors more difficult. The most affected area is the SPI handling in the FatFS code. Originally named 'mm_llc_spi1.c', I felt this was not cleanly integrated, so I rewrote it. Maybe it's not better, but it is different :) The FreeRTOS code is almost completely untouched, except for moving an #if around that allowed compiling the trace code (configUSE_TRACE_FACILITY) without requiring the task suspend code (INCLUDE_vTaskSuspend). In the end, this was probably irrelevant, since I compiled the task suspend code in anyway. Things I wish were different: A collection of random little thoughts of things I wish were different. These are just MY opinions, based on the way I do things. It's not to say the original authors were wrong. It's just the way I'd make things, if I were smart enough to write this stuff from scratch. Most people probably shouldn't even read the following list... While FreeRTOS attempts to isolate the user from system data structures, it's a little *too* aggressive. These typedef'ed structures should be in a header file, so applications can at least use sizeof() to help determine memory allocation. Everything is done through recasted void* pointers. It would be neat if FreeRTOS had a xDelayTaskUntil() that also took one or more queues as a blocking item. I want to run a task every 'n' milliseconds, but if something shows up in a queue, process it early. Perhaps this could work like Unix's select(). Or perhaps a variadic function that takes xQueueHandles as parameters. I dont' care for FreeRTOS's use of portBLAH typedefs for portable types. The world is pretty used to U8, U16, N32, and BOOL for unsigned char, unsigned short, signed int, etc. FreeRTOS also seems to require declaring too many things as 'signed', which should be a default. I'm sure this is done for portability, but I find the types are not as intuitive as they could be. Another minor itch is that all function names and types start with 'x'. I would have preferred 'freertos', or better, a user-definable one, via a #define macro. I think programmers forget that their package may be integrated into a larger system, and while their naming convention works well for their purpose, it may not scale well. FatFS and LPCUSB are guilty of this as well. FreeRTOS has a couple errors in several of the modules regarding type punning. I understand what type punning is, but I don't know how to fix it safely. Perhaps RB will fix those up in the next release. FatFS changes return types too often, particularly for errors. There's the errors from the SPI routines, the MMC routines, the disk routines, and the top layer FatFS code. There should be unified errors for everything, so that errors can be cleanly communicated up the stack. FatFS can't go from file descriptor to filename. I haven't figured out a clean and reliable way to map a fd back to a filename (FatFS f_stat() needs a file name). I thought about malloc()'ing space in the openFiles_t structure and copying the filename when the file is opened. However, paths can get up to 128 characters, and only _fstat() needs that information. This seems very wasteful. FatFS wants the user to provid the get_fattime() function. FatFS should really have a file for locally provided functions. It's already specific to the SPI or IDE port implementation. As such, it should be stubbed out to return 0 if the function isn't provided, or allow the user to implement in the platform specific file (basically, an equivalent of syscalls.c, but internal to FatFS). FatFS has naming conventions that I don't like. It exposes too many internal function names that should be declared static. Structure names like 'FIL' are ambiguous, and too likely to collide with other libraries. Functions should be preceed by the supporting module or library. All FatFS functions should be in the form of fatfsOpen, fatfsClose, etc. LPCUSB is not organized quite the way I'd do it. The USB protocol engine defines need to have their names modified and moved into the lpc210x.h. Newlib lacks certain calls on the ARM7 platform. sync() and chmod() do not exist, while mkdir() does, but wit no corresponding _mkdir() support in syscalls.c. Returning ENOSYS is easy enough, and doesn't take but a few instructions. Providing support for a wider range of calls would be good, taking into mind things like FatFS that provide file system support, etc. The Olimex board COMPLETELY lacks documentation (at least, that I've been able to find). It's up to the user to guess what the slide switches are for, etc. It's probably pretty obvious to someone who's used the LPC2000 parts before, but if you're buying a board to get started, you have to waste time figuring out how to use it. Even a simple Xerox'ed sheet would have been sufficient. The Olimex board also lacks the ability to control the BSL line from the serial port. Reset works, but without being able to flip the BSL switch, it has little value. The buzzer on the Olimex board is useless. Had it been connected to one of the PWM outputs, some simple sound synthesis would have been possible. At best, it demostrates you can toggle I/O pins fast enough to make noise. However, unless you want clicks in the output, you have to disable interrupts. And why *two* port pins? One would have been sufficient. I would have preferred to have two more LEDs, rather than the buzzer.