I want to control the frequency of the function generator IC XR-2206 with voltage (instead of the usual way with a pot).
Figure 10 (see attachment) in the datasheet show a way (I think): http://www.jaycar.com.au/images_uploaded/XR2206V1.PDF
I do not fully understand how it works. I plan to use a DAC that output 0-3V as sweep input.
In the middle of the figure it says ±3V.
Pin 7 outputs 3V and the sweep input is 3V.
When sweep input is 0V Pin 7 is +3V, correct?
What comes the negative voltage from? Is it because the sweep input is 3V?
What values for Rc and R?
The datasheet reads 1uA to 3mA (max) on pin 7. How do I calculate the current on pin 7 in this case?
I think the GND of the Arduino and DAC should be connected to GND of XR-2206? Is this correct?