Hello,
I use openocd for programming and debugging Luminary-Micro devices,
there is a special Problem with them:
It is possible to write a Target-Software that prevents openocd(or all other
jtag-tools) from
Communicating with the TI/Luminary Micro LM3Sxxxx Controllers.
As I read in Luminary-Forum there are two possible reasons:
- Using the JTAG pins as GPIO
- Setting the Clock configuration to something invalid/out of spec.
In my Case this was caused through a incomplete erase and download sequence.
The only way(*1) to recover a Controller form this State is a special Sequence
which is described in
the Luminary-Micro Datasheets :
You have to Assert and hold the RST signal.
for five times :
{
Send 50 TCK/SWCLK cycles with TMS/SWDIO High to ensure that both JTAG and SWD
are in their reset/idle states.
Send the 16-bit JTAG-to-SWD switch command, 0xE79E, on TMS.
Send 50 TCK/SWCLK cycles with TMS/SWDIO High to ensure that both JTAG and SWD
are in their reset/idle states.
Send the 16-bit SWD-to-JTAG switch command, 0xE73C, on TMS.
}
Release the RST signal
Wait for 400ms
Power-Cycle the microcontroller.
This sequence triggers a mass erase, the whole flash will be deleted(*2).
This is a procedure which has user Interactions, is it possible to add such a
sequence to openocd?
Has someone an idea how this could be implemented?
Perhaps there is already something similar in openocd what can be taken as
template.
It is possible to keep user-interactions outside of the sequence, setting and
releasing reset could
be done before and after executing the command, but openocd prints out a
errormessage when I hold
the reset, entering a command is not possible then.
Regards
Arne
ps:
1: sometimes, depending on what is wrong with the programmed code, it helps to
steel the external
clock(if used) from the Luminary-Device.
2: This procedure works with the LMFlashProgrammer Tool which is downloadable
on
http://www.luminarymicro.com/products/software_updates.html, but for that I
always need to borrow a
computer with windows.
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