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For anyone who needs a 12 bit A/D in a PIC, I have successfully used the new 18F8723. PBP doesn't explicitly support the chip, but if you compile for a 18F8722 and set "DEFINE ADC_BITS 10", the result from ADCIN is 12 bits. Even if you only need a 10 bit result, the new chip has lower jitter.
PBP2.47, PBP2.50 and PBPL2.50 all seem to work fine.
Thanks Charles for the info.
Where did you find this part?
Sample from MicroChip?
Sure would like to have a few of these around. You are quite pleased with the 12 bit performance?
-Steve
Yes, these were samples, but I have 100 pcs on order. Should have them any day now.
The A/D's on these parts are definitely less noisy. I plan on switching over to them 100% as soon as I run a few more tests.
Hi Charles,
Are you using an opamp to buffer and filter the input to the AtoD channels?
Thanks,
-Steve
No, I'm measuring power supply voltages, so my source impedance is low. I generally use a voltage divider with about a 2K source Z and a .1uF cap to the analog GND plane right at the PIC's analog input. I get good results. It also helps that I use a 0.1% low-noise Vref and average at least 6 samples.