Hai i am using LPC1857 in a custom designed card. I have followed the hardware design of MCB2300. My board was working well for months and suddenly it stopped working. Since it was working alright earlier, i didnt doubt the hardware design and hence made 4 more such boards. But now none of the boards are working/booting. In JTAG ( i am using both keil ULINK2 and Segger JLINK with KEIL microvision IDE) the core/cpu is not getting detected now. Also, i am not able to get any clock signals in the XTAL1 & 2 pins to which i have connected the 12MHz crystal. Even i tried giving an external oscillator signal to the GP_CLKIN but still not booting.
Can anyone help me out to solve this issue?
The microcontroller core got detected when i selected SWD instead of JTAG in the KEIL IDE. But earlier when i was using the prototype board, i was working in JTAG mode. DOn't know why it is not working in JTAG mode now and only in SWD
I googled for "jlink boundary scan", these are just the first 3 links which I think could show something useful: