Hi,

I have 3 home made boards, very similar design, all like olimex boards.

SAM7S64 has been working for the last year without any problems.

SAM7X256 stopped working in the first version, I saw crystal not oscillating.
Created a new board, transferred the MCU, no change.

Ordered a new SAM7X128, soldered --> bingo, it worked with the SAM7S64 software right from the beginning.

After two weeks same thing as it was with the SAM7X256.

No more main clock..

What I checked: JTAG connected (OOCDLink+OOCD), reset init, reset peripherals mww 0xfffffd00 0xa5000004, enable main osc mww 0xfffffc20 0x00004801.

It works for SAM7S64, does not work for SAM7X128 anymore.
SAM7S64: there is 18.432MHz AC with 1.2V DC offset.
SAM7X128: just some DC offset, no oscillation.

I also tried not to measure on the crystal pins, but turned on PCK for a pin, no difference.
Changed the crystal, tried 16MHz, 8MHz, different capacitors.

ERASE and TST are not connected for SAM7X128, SAM7S64 has them pulled down with 1.5k resistor.

The first "defect" SAM7X256 works with external clock without problems.


Anyone experienced XIN problems with SAM7X this way?
Are the xtal pins very sensitive on this uC?

Thanks for any help.

I replaced the SAM7X128 with a new one, Main Oscillator is running again..

I will build a small board for the old one to investigate further.