12-19-2016 02:41 AM
I am Using CPLD XC9536XL as a replacement for its 5V counterpart XC9536.
This XC9536XL is operating with 3.3V.
I have replaced my existing part 9536 with 9536XL on the PCB by doing hand soldering on the BGA balls. it worked well. it got programmed and functioned good, which is as a proto.
when i Have received a new fab with 9536XL directly mounted on the PWA, i could not able to program the device.?
surprisingly the same board from new fab, was removed the CPLD and the Same removed part was hand soldered. and it started working.
i could not able to find what going wrong.? kindly help on it.
12-19-2016 02:57 AM
Looks like the soldering is not done correctly.
12-19-2016 03:28 AM
we performed BGA Xray for the assembled board and didn't found any issues.
And when tried programming, it says "There are many Unknown devices connected".
12-19-2016 03:37 AM
Check the below links where the similar topic is discussed.
12-19-2016 03:46 AM
I have read that post and verified the TDO pin for any shorts, but no use.
Is there any further debug i can do on JTAG signals?
As per my sch I have connected TDI pin to 5V pull up through 10K resistor.