I have designed a pcb to run the LPC 2129 in the LQFP64(64 pin) package. As the system was too congested i decided to skip the 3.3 Vdda connection believing it to be required only for the ADC as a reference voltage. But the problem now is than on the 2 CAN controllers which i am using CAN1 is working fine while CAN 2 refuses to work. The pins just refuse to drive. There is no fault in the code as the similar code works on the demo board. There is no fault in the circuit or in the connections as i have personally checked all of the wire connections myself. There is no signal on the PINS on the microcontroller. Is this problem due to the non connection of the 3.3 Vdda pin ???
Applying 3.3 Vdda did not make a difference it still doesnt work
Then you have a number of alternatives to consider. - you have broken the hardware - your software is buggy (like having selected wrong multiplexing for CAN2 pins) - you have missed to turn on power for CAN2 - or does it too late in the code - you have a PCB error (beside the Vdda error) - ...
Thanks fr the support it was a PCB error after all.