Just an idle thought. A serial I2C DAC with a 6 pin package needs gnd,vcc,sda,scl,out. If you can select the I2C address as a variant of a base part number, that leaves one free pin... I'd like that pin to be a GPIO, or just a digital out. I'd like to control the ENA pin of an OCXO with the same I2C bus as the DAC.
Is there such a beast, and if not, why not! Maybe a 6 or 8 pin uC programmed to act as a I2C DAC? I need (ok, want) 12 bits.
On a sunny day (Sat, 31 Oct 2009 10:21:52 -0700 (PDT)) it happened snipped-for-privacy@netzero.com wrote in :
I think one could program some 8 pin PIC to do i2c controlled PWM out. Speed? I have done software i2c slave mimic in a PIC in the past. Sorry not open source code, was in a project. A soft PWM loop is simple. PIC 12F629?
Hmm. I'm trying to get rid of the PWM we have already on board, by using a "real" DAC. But the tought occurs that the VCXO needs a Vc of 0.15V to 3.15V. I could just pop a small comparator on the DAC output, and use the comp's output to kill the VCXO when the Vc goes below say .1V. Hmmm...
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