Hi,

we just got first prototypes of a new board with LPC2468 (beside an
Actel Flash FPGA, SDRAM and MicroSD slot). Without DBGEN, the LPC
responds to an UrJTAG "detect" with a proper response that I expected
for Boundary Scan mode:

IR length: 3
Chain length: 1
Device Id: 01000000000111110000000000101011 (0x00000000401F002B)
Manufacturer: Philips Semi. (Signetics)

But with DBGEN, UrJTAG is only able to detect the chain length (4 in
this case, as expected, not 3) and immediately afterwards TDO becomes
quiet (i.e. stays at zero level).

What may be the reason? Code Read Protection? Bad system or JTAG clock
(was set to 40 kHz, JTAG signals look fine on scope). What else? So
far I only checked the JTAG signals, reset line (high) and clock (25
MHz slightly rounded square @ 1.8V). During my next experiments
tomorrow I'll probably concentrate on establishing contact to the
bootloader via UART.

Any hints are welcome!

Kolja

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> But with DBGEN, UrJTAG is only able to detect the chain length (4 in
> this case, as expected, not 3) and immediately afterwards TDO becomes
> quiet (i.e. stays at zero level).

It was the JTAG adapter that was constantly driving nRESET low.

K.
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