Info: ADC error on KEIL MCB2300

Started by Benny Simonsen June 14, 2008
I have had some problems with ADC readings on a V3.1 KeilMCB2300 board (LPC2378).
The reason is that P1.30 (AD0.4 which by mistake is called AD0.7 in the schematic) is pulled up to 5V.
As written in the manual the ADC pins are 5V tolerent, but if just one of them (used as ADC or not) is pulled up to > VREF it will give ADC errors.
To avoid this problem on the evaluation board remember to set P1.30 to output.
Hope this info will save a little time for some of you.
Best Regards
Benny Simonsen

An Engineer's Guide to the LPC2100 Series