I have concerns about DAC of Due as below;
1) The output voltage does not go 0 Volt even if I write 0 as output value. The DMM readings of DAC0 pin was as below;
0: 0.548V 100: 0.599V delta 51mV 1000: 1.078V 1100: 1.131V delta 53mV 2000: 1.610V 2100: 1.664V delta 54mV 3000: 2.143V 3100: 2.196V delta 53mV 3995 : 2.673V 4095: 2.727V delta 54mV
It seems that voltage swings from 0.548V to 2.727V when I wirte 0~4095. The linearity of the DAC sems OK for my application.
2) The Voltage at 3.3V rail was 3.235V.
3) I need voltage swing starting from 0 Volt to 10 Volt.
4) I know I have to use OP amp to amplify the output of DAC0.
5) The problems are; a) The voltage is not starting from 0 Volt. How can I make it Zero Volt using OP Amp?? I also need to amplify Max output to 10 Volt. My requirement is to make DAC0 outpout of 0.548V to Zero Volt after OP Amp and 2.727V to 10V. How?? b) I need the DAC output stays Zero when booting and stay Zero until I write new value BUT I found the DAC0 output went to 3.235V when booting.. How can I solve this problem??
6) I tried external 12bit DAC, MCP4728, and the voltage swing was from 0V to 3.3V which is OK but I really want to use internal DAC if at all possible.