Lpc2000

I have been evaluating the LPC2138 for a few months now using the 
Keil MCB2130 board, Arm compiler, and Arm Multi-Ice emulator. All 
peripherals have been evaluated and the only remaining task was to 
verify the 50uA sleep current. The LPC2138 part on my Keil board was 
a pre-production part with a sleep current of 150uA.

So, I got production samples of the LPC2138 and and had one placed 
on the evaluation board. Everything flashed ok, but I noticed the 
UART did not behave properly. I evaluated the UART using the Modbus 
RTU protocol. It seems to receive packets ok, but the response is 
always garbage. However, if I perform a hard reset after powerup 
using the reset button on the evaluation board, everything works 
fine.

I have no idea what is wrong. I do know the previous part worked 
fine, and this part works fine only after a hard reset. Switching 
the power supply off then on does not work. It seems I have to power 
the board, then do a reset. Go figure.