In SX Microcontrollers, SX/B Compiler and SX-Key Tool, alex41 wrote:

Here is a post when I was working on this a while ago.


http://forums.parallax.com/forums/default.aspx?f=7&m=251301&g=254365#m254365

The Link has a much shorter version of the one posted  a few days ago. The code running the LTC1257 is identical. 


Here is the meat of the program running the chip.

  PinLoad = 0                 ' activate chip to receive data
  SHIFTOUT Din,Clk,MSBFIRST,Pottime_MSB ' send high nib
  SHIFTOUT Din,Clk,MSBFIRST,Pottime_LSB ' send low byte
  PinLoad = 1              ' de-active chip to output voltage

I don't know for sure if the above is even correct. It works, but I don't know if de-activating the chip is correct. Above Bean said that the DAC chips put out a constant voltage. When I deactivate the chip am I shutting off the chip and is that why I get such a rough signal? I figured out the above code by trial and error and not sure if it is the right way to go about it.


This project has been sitting in my "to finish" box for a while and I want to know if it will work. It seems like I'm pretty close.


Leon,
The DAC does put out a fixed voltage when using a fixed value. My voltmeter reads it as a steady voltage. My scope shows a signal with a lot of noise in it. That's my problem.


Thanks for everyones help so far.

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