Other Parts Discussed in Thread: ENERGIA, TPL0102-100, TPL0401A-10, REF5030,
I have problems with programming DAC.
First of all my project has one part where I would need to get a linear analog voltage from -1.5v to 1.5v. idea was to use Digital potentiometer to get 0->3V and then feed into opAMP with 1.5v on noninverting input so to "split" it in half and in the end obtaining -1.5V <-> 1.5V.
well, analog circuitry part works very vell, but I can't get the 0->3V.
I have tried TPL0401A-10 and it works wery vell ( I am using Tiva C series platform and Energia for control). problem was that TPL0401A-10 has 128 taps giving me a very low resolution in the end. that is why I switched to TPL0102-100 for its 256 taps and with the same code (of course, an address has been changed and a number Val to 255) in the end, I get something from the picture ( I am using 10k pull-up resistors, same as for the TPL0401A-10).
Then I changed to DAC121C081 and made little evaluation board, where DAC is powered from REF5030 and it has 10K pull-up resistors. (again I am using Tiva C and Énergia with Adafruit MCP4725 library for DAC and it works, problem is that minimum on DAC is 0V, which is ok but maximum I get is 0.2V ?? ( see figure DAC, where Tiva has driven DAC and recorded ADC value directly).
Can anyone help me to solve programming side for both DAC121C081 and TPL0102-100?
I would prefer DAC for its much better resolution but I would also like to know what is the problem with TPL0102-100.
Thank you all in advance.