Hi,
Most PICaxes have an on-chip DAC (controlled by DACSETUP and DACLEVEL commands) but I've only used it with M2 devices. However they all seem similar and have several limitations:
- The resolution is only 5 bits, i.e 32 (or strictly 33) dc levels.
- The output impedance is very high (and variable), so an external (Op-)Amplifier buffer is often necessary.
- The Output pin is "shared" with other functions (e.g. the Serial Out/Programming pin on M2 devices). On the 40X2 the output appears to be shared with the (external) negative Reference voltage and the Comparator2 Output, etc..
Generally, it is better to use one of the PWM outputs, followed by a simple Low-Pass filter, which can give up to 10 bits resolution (and even close to that accuracy, with care).
Cheers, Alan.
