Message #1 Posted by Eric Rechlin on 13 Aug 2008, 1:15 a.m.
I just did the full set of modifications to my 20b:
- JTAG interface
- RS-232 level shifter
- Clock crystal
I've got some photos:
Closeup of level shifter:
It's not quite as crooked as it looks in the photo. It's a little off (long story...), but it's close enough that nothing is connected wrong.
Closeup of crystal:
Note that the schematics from HP are wrong -- 15 nF capacitors would be the wrong value; I used 18 pF capacitors (three orders of magnitude different!).
Unfortunately, I am having a problem.
I bought the SAM-ICE to use as a JTAG interface to connect to the 20b. I installed the latest software from Segger on my computer (Windows Vista x64). When I run the J-Flash ARM software and try to connect to the 20b, I get the following error:
Could not find supported CPU core on JTAG chain
Bad JTAG communication: Write to IR: Expected 0x1, got 0x7
(TAP Command : 2) @ Off 0x5.
Failed to connect
Any idea what that means? I am running the following software:
Segger J-Flash ARM V3.90
Compiled 11:34:57 on Aug 12
(Apparently it was just posted earlier today!)
I suppose this is mainly directed at Cyrille, but if anyone else here has successfully connected to the 20b with a SAM-ICE, I'd like to hear your experiences.
The solder joints are all perfect, so I am thinking this is a software misconfiguration, but maybe I got something wrong.