Using Bus Blaster v4 with STM32F4x SWD

notes.md

Using Bus Blaster v4 with STM32F4x SWD

For SWD (instead of normal JTAG) you need a different CPLD "buffer logic" image on the Bus Blaster, the KT-Link compatible ones seem like the recommended means.

# with buffer logic at https://github.com/dergraaf/busblaster_v4/blob/master/ktlink/ktlink.svf
# via http://dangerousprototypes.com/forum/viewtopic.php?f=37&t=5954 from https://github.com/mchck/mchck/wiki/Getting-Started#wiki-bus-blaster
curl -O https://github.com/dergraaf/busblaster_v4/raw/master/ktlink/ktlink.svf
openocd -f board/dp_busblaster_v3.cfg -c "adapter_khz 1000; init; svf /Users/natevw/Downloads/ktlink.svf; shutdown"

Then start OpenOCD with the necessary configuration and connect to it:

openocd -f interface/ftdi/dp_busblaster_kt-link.cfg -c 'transport select swd' -f target/stm32f4x.cfg

# via http://openhardware.net/Embedded_ARM/OpenOCD_JTAG/#testocd
telnet 4444
> reg   # should show registers

To program back the JTAG-Key, I think the file you need is https://dangerous-prototypes-open-hardware.googlecode.com/svn/trunk/Bus_Blaster/buffer_logic/BBv4-JTAGkey-selftest-v1.1.svf, the selftest in the filename is a little weird but accodring to http://dangerousprototypes.com/docs/Bus_Blaster_v2_manufacturing_resources#Hardware_selftest:

The hardware self test is part of the factory jtagkey-compatible buffer shipped with the Bus Blaster v2.

…so maybe that's fine.

Helpful links

• http://bgamari.github.io/posts/2014-08-23-swd-with-busblaster-and-openocd.html (general overview of SWD w/BB)
• http://dangerousprototypes.com/forum/viewtopic.php?f=37&t=5954 (buffer logic)
• http://bgamari.github.io/posts/2013-07-24-flashing-busblaster-cpld-with-openocd.html (how to flash it — just had to move mode jumper to "Update Buffer" on BBv4)