swddude is very young pre-alpha software. Caveat downloader.
swddude is a simple program that can flash code onto ARM Cortex
microcontrollers, such as the Cortex-M0 and M3, using SWD. It's designed to use
programming interfaces built on the FTDI FT232H interface chip.
Larger ARM microcontrollers have JTAG interfaces. OpenOCD and friends already
do a great job flashing these micros. But for smaller parts, such as the
LPC11xx/LPC13xx series, ARM has defined a new low-pin-count debug interface
called SWD. OpenOCD doesn't yet support SWD. In fact, when we started writing
swddude, no software on Mac or Linux could do what we wanted!
It's a shame not to be able to use these powerful little microcontrollers, so we
wrote swddude to scratch this itch.
Out of the box, swddude can flash code onto the following chips:
- NXP LPC11xx series (Cortex-M0 based).
- NXP LPC13xx series (Cortex-M3 based).
It may also work with other NXP Cortex parts that have similar memory maps and IAP invocation methods, such as the LPC17xx series.
It was designed very specifically for this purpose, and extending it to other varieties of chips will require refactoring. We're likely to do this in the near future, because we've got a box of LPC18xx, STM32F4, and EnergyMicro eval boards just begging to be used.
You'll need a supported programmer and, of course, a supported microcontroller
with a SWD interface. Currently swddude supports using the Bus Blaster (v2.5
programmed with the KT-link compatible CPLD configuration) or any FTDI
development board with an FT232H or FT2232H chip that has been wired to the SWD
lines of your microcontroller.
Wire up your micro using the configuration described in swd_mpsse.h.
Build a recent version of libftdi. The version commonly included in package
managers as of this writing (0.19) doesn't support the FT232H's MPSSE feature,
which we use to convert it into a SWD interface. For best results, build
libftdi from HEAD.
After checking out swddude, build it like so:
$ cd swddude/source
$ make swddude release
This will deposit a swddude binary in swddude/source/release.
To program your microcontroller, you'll need to have your desired firmware in
binary format -- not ELF, and not Intel hex. Assuming it's in a file called
firmware.bin, you run:
$ swddude -flash firmware.bin -fix_lpc_checksum
This will default to the um232h programmer (FTDI's FT232H development board)
configuration. If you are using a Bus Blaster, you should add
-programmer bus_blaster to the command line above.
That last option, -fix_lpc_checksum, adds the vector table checksum expected
by the NXP LPC series. Without it, your firmware won't run! If some other tool
has already written the correct checksum into your firmware, you can omit that
option.
swddude can flash the LPC1114 and LPC1343 on their respective LPCxpresso
breakout boards, as long as the proprietary programming system (on the side of
the board with the USB connector) has been disabled by cutting the bridge
traces.
Known issues:
- Error reporting is not great. Most failures just print a stack trace, which isn't helpful if you're not familiar with the source code. In general, it's worth retrying at least once -- sometimes the SWD communications just need to be reset.
swddudemakes no attempt at identifying the chip it's programming. If you try programming an unsupported chip, it may do very bad things -- there is no safety net.- On the LPC1343 specifically, the SWD interfaces sometimes gets "stuck" and requires a power-cycle. This will show up as failures very early during communication (often referencing the IDCODE register).
The source code contains the following top-level directories:
build: Anton Staaf's build system.libs: Anton Staaf's support libraries, several of which we use. (We currently include more than we strictly need here.)source:swddudeitself.