Hello everyone.

I'm a new to this mailing list.
This post is about DCC message speed.

I tested DCC message communication. JTAG interface is a generic FT2232. OS
is Windows XP.
A result is recorded.
http://www.youtube.com/watch?v=nGxCf5natAo

As you watched this video, the speed of dcc message is very slow.
I understand that a dcc data is multiplexed with other JTAG communication
and cannot establish high speed communication, but this result looks to be
not only from band witdh limit. I guessed this is due to low frequency of
polling to target.

I tryed to trace source code tree to find the code which define the frequency.

What I found is;

"target_request()" in target_request.c calls "target_asciimsg()".

"cortex_m3_handle_target_request()" calls "cortex_m3_dcc_read()" and
"target_request"

In "cortex_m3.c", "target_register_timer_callback()" in
"cortex_m3_init_arch_info
" registers call to "cortex_m3_handle_target_request".

So I coped with target_register_timer_callback, but could not figure out in
what logic it set calling frequency.

Please give me the hint of usage of the function or any thoughts with it.
I think it is more usable if the frequency is set from OpenOCD commands.

Any help is deeply appreciated.

Yasuo Kawachi

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