Forum: ARM programming with GCC/GNU tools Error validating JTAG scan chain

Author: Lukas S. (Guest)
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I have build a JTAG adapter with a FT2232C and the layout from

The USB-Serial converter (Channel B) works fine, but when I try to use

c:\Programme\openocd-2006re115\bin\openocd-ftd2xx.exe -f

the TCK Pin goes low (pulled high with 47k) and remains low until I
disconnect the JTAG interface and OpenOCD returns this error:

Error:   jtag.c:1149 jtag_validate_chain(): Error validating JTAG scan
chain, IR mismatch, scan returned 0x3f

I've checked all connections but the problem remained :-(

My at91sam7s256-jtag.cfg File:

#define our ports
telnet_port 4444
gdb_port 3333

#commands specific to the Amontec JTAGKey
interface ft2232
ft2232_device_desc "Dual RS232 A"
ft2232_layout usbjtag
ft2232_vid_pid 0x0403 0x6010
jtag_speed 2
jtag_nsrst_delay 200
jtag_ntrst_delay 200

#reset_config <signals> [combination] [trst_type] [srst_type]
reset_config trst_and_srst srst_pulls_trst

#jtag_device <IR length> <IR capture> <IR mask> <IDCODE instruction>
jtag_device 4 0x1 0xf 0xe

#daemon_startup <'attach'|'reset'>
daemon_startup reset

#target <type> <endianess> <reset_mode> <jtag#> [variant]
target arm7tdmi little run_and_halt 0 arm7tdmi

#run_and_halt_time <target#> <time_in_ms>
run_and_halt_time 0 30


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