Test result of ARM-USB-OCD-H - flashrom

11 Jul 2014


      For archive purposes and recording of my email:
The test result I posted on IRC.
Best regards,
Ruud Schramp
<ruud> sudo ./flashrom -p ft2232_spi:divisor=16,type=ARM-USB-OCD-H -w test.bin  flashrom v0.9.7-r1822 on Linux 3.2.0-60-generic (i686) flashrom is free software, get the source code at http://www.flashrom.org%C2%A0%C2%A0Calibrating delay loop... OK. Found SST flash chip "SST25VF016B" (2048 kB, SPI) on 
ft2232_spi. Reading old flash chip contents... done. Erasing and writing flash chip... Erase/write done. Verifying flash... VERIFIED.
[23:05] <ruud> I Noticed that ARM-USB-OCD-H is still noted as "untested".
[23:05] <ruud> Now it isn't untested any more: It works!
[23:08] <ruud> But please note that I used a rather high divisor. Using the default 
(2) resulted in the chip not being detected, the bits seemed to be 
shifted one position, so the ARM-USB-OCS-H seemed to read the value of 
the previous clock-cycle.
[23:09] <ruud> It may be caused by the long wires of my breadboard.. but it seems more like a timing issue than a noise issue.
[23:16] <carldani> yes, timing due to either long wires or a slow chip
[23:17] <carldani> capacitance of the wires can mess with the timing a lot, e.g. by making flanks less steep and thus needing more time until a level change is 
reached
[23:18] <carldani> and other funny business
[23:18] <carldani> ruud: thanks for the report!
[23:18] <carldani> ruud: would you please send the report by email to 
flashrom@flashrom.org as well? That way we have your e-mail address in 
case we ever need retesting for that programmer
[23:19] <carldani> ruud: and please mention the problems with the default divisor in your 
mail, preferably also with noting the wire length (rough estimate or 
measurement in cm)
[23:20] <ruud> Will do.
[23:21] <ruud> I used a standard small breadboard (5cm x 8cm approx)
[23:22] <carldani> stefanct: If I had known about this two weeks ago, I would have been able to do something about it.
[23:22] <ruud> Standard olimex provided ribon cable between Olimix ARM-USB-OCD-H of about 15cm
[23:22] <ruud> Wiring on the breadboard <4cm
[23:23] <ruud> Power decoupled using a 100uF elco
[23:23] <carldani> do you know what frequency you get with a divisor of 2?
[23:24] <ruud> Power supply: 2  big 1.5 Volt batteries in series (3V)
[23:24] <ruud> Unfortunately I do not have a scope or frequency counter.