[ECOS] Problems in eb40a uC - TSB12LC32 LLC interfacing

[sandeep <sandeep at codito dot com>]

hi folks,

we have got some troubles with a piece of hardware involving EB40A uC and 
TSB12LV32 LLC. The hardware people say that they have done the hardware 
interfacing as suggested by TI documentation.

earlier we could not even read LLC registers correctly. later with some bit of 
experimentation we found that keeping the clocks for uC and LLC to same @ 40Mhz 
was promising on this hardware setup.

initially both were operating at different  frequencies, and we have had enough 
troubles getting serial communication for I/O, jtag and LLC reads working 
together - and had tried various frequency combinations (even both uC and LLC 
operating at same frequency as low as 10Mhz, with the help of h/w guy).

we isolated LLC register read/writes into a separate test case and were 
successful in being able to read LLC registers correctly, in 8bit handshake mode 
 (we s/w guys have some doubts on the this handshaking implementation in 
current setup, but well..).

One thing that we found bit shady that in our test case, where we were reading 
LLC registers in a loop (kinda synchronously) we got the correct reads happening 
at NWS >= 1 (TDF immaterial) but with the same working EBI_CSR2 configuration, 
in actual code correct reads happen only for NWS >=2.

Writes to LLC are still not happening successfully. In our small test, we write 
some fixed bit pattern in writable LLC register and read the register back, this 
is how we determine if our writes have been successful or not.

We have tried cycling through various EBI_CSR configuration, even tried 
inserting delays b/w write and readback. nothing seems to work for LLC register 
writes.

In case someone out here has worked on similar/same h/w configuration, can we 
get some guidance on - whether (s)he also encountered sort of basic register 
read/write issues and how did (s)he manage to overcome that, in s/w and/or in h/w.

we are not ruling out the possibility of s/w issues yet. we built ecos for eb40a 
and then in our test configure the EBI_CSR for our LLC and then issue the LLC 
registers write/read calls. Are we missing out on any step? Any advice on what 
to further explore in s/w and/or in h/w for proceeding ahead would be a great 
help, since correct read/write from/to LLC registers is basic thing required for 
  any meaningful progress in what we are doing.

Our search on internet brought us to some people on Linux related mailing lists, 
who have faced trouble with the hardware combination in question.

--
regards
sandeep
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