UPSD3254A-40U6 - Board not up - urgent

balaji · ‎2004-10-18

Posted on October 18, 2004 at 17:21

balaji · ‎2011-05-17

Posted on May 17, 2011 at 12:03

I have designed a new PCB for UPSD controllers. I am currently using the free samples of UPSD3254A-40U6. But the board is not up. When I try communicating with ULINK JTAG interface, it give an error msg as ''No UPSD JTAG device found''. I checked the reset circuitry timing and even provided more(30ms-150ms) than what was stated in the data sheet (1ms). I checked the clock circuitry, I am using a crystal of 36MHz from Citizen make (CM309S36.000MABJTR), there I could see oscillation only in XTAL2 pin, but I could not see any oscillation in XTAL1 pin(its a 3rd over tone crystal hence provided the additional LC circuitry as recommened by ST's APP note), is there any problem with the crystal selection.

Can any one help/guide me, I am struck at my development......

jdaniel · ‎2011-05-17

Posted on May 17, 2011 at 12:03

Balaji,

Since it seems clear you suspect a clock problem, why not try to rule that out. Try removing the crystal and LC filter and replace it temporarily with a 36MHz clock oscillator (active). If the board comes up then, you'll know that your 3rd OT crystal was the problem. Also, it should be somewhat telling that ST themselves use an oscillator rather than a crystal for the 36MHz clock on their eval board.

Best Regards,

Phaze426