bryne
Posts: 2
Joined: Wed Apr 03, 2019 3:30 pm

JTAG for Raspberry Pi unexpected tap

Wed Apr 03, 2019 7:48 pm

Hey,

I want to debug my Raspberry Pi 1 Model B revision 1.2 with JTAG. I use the FT2232H Mini Module and OpenOCD (v0.10.0).

After booting the kernel and starting openocd I get the following output:

Code: Select all

Open On-Chip Debugger 0.10.0
Licensed under GNU GPL v2
For bug reports, read
	http://openocd.org/doc/doxygen/bugs.html
adapter speed: 1000 kHz
none separate
raspi.arm
Info : clock speed 1000 kHz
Info : JTAG tap: raspi.arm tap/device found: 0xf83ad07f (mfg: 0x03f (Silicon Storage Technology), part: 0x83ad, ver: 0xf)
Warn : JTAG tap: raspi.arm       UNEXPECTED: 0xf83ad07f (mfg: 0x03f (Silicon Storage Technology), part: 0x83ad, ver: 0xf)
Error: JTAG tap: raspi.arm  expected 1 of 1: 0x07b7617f (mfg: 0x0bf (Broadcom), part: 0x7b76, ver: 0x0)
Error: Trying to use configured scan chain anyway...
Warn : Bypassing JTAG setup events due to errors
Error: unexpected ARM11 ID code
I get these errors with my own code as well as with the code provided by dwelch67 here: https://github.com/dwelch67/raspberrypi ... er/armjtag

I use the same wiring and checked it multiple times (UART works without problems):

JTAG: (FT board left, Raspi right)
TCK: CN2-7 P1-22
TDI: CN2-10 P1-7
TDO: CN2-9 P1-18
TMS: CN2-12 P1-13

UART:
TXRX: CN3-26 P1-10
RXTX: CN3-25 P1-8

Ground:
GND: CN2-2 P1-6

Raspi to Raspi:
TRST: P1-1 P1-15

FTDI board to FTDI board:
VCCIO: CN2-1 CN2-11
VCC: CN3-1 CN3-3

Here are the config files I use for openocd:

raspi.cfg

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telnet_port 4444
gdb_port 3333

adapter_khz 1000

set  _CHIPNAME raspi
reset_config none
set _CPU_TAPID 0x07b7617F

jtag newtap $_CHIPNAME arm -irlen 5 -expected-id $_CPU_TAPID

set _TARGETNAME $_CHIPNAME.arm
target create $_TARGETNAME arm11 -chain-position $_TARGETNAME
ftdi.cfg

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interface ftdi

transport select jtag

ftdi_vid_pid 0x0403 0x6010
ftdi_channel 0

ftdi_layout_init 0x0018 0x05fb
ftdi_layout_signal nSRST -data 0x0020
Does anyone know what the problem is?

bryne
Posts: 2
Joined: Wed Apr 03, 2019 3:30 pm

Re: JTAG for Raspberry Pi unexpected tap

Wed Apr 10, 2019 6:37 pm

Ok, so I decided to try a fresh start. I removed and reconnected all cables, reinstalled all the software and finally it worked.

Code: Select all

Open On-Chip Debugger 0.10.0
Licensed under GNU GPL v2
For bug reports, read
	http://openocd.org/doc/doxygen/bugs.html
adapter speed: 1000 kHz
none separate
raspi.arm
Info : clock speed 1000 kHz
Info : JTAG tap: raspi.arm tap/device found: 0x07b7617f (mfg: 0x0bf (Broadcom), part: 0x7b76, ver: 0x0)
Info : found ARM1176
Info : raspi.arm: hardware has 6 breakpoints, 2 watchpoints
I tried to recreate the error to search for the cause but without a result.
So it feels kind of disappointing :D

The config files and the openOCD version are unchanged.
Also the wiring is the same as above.

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