BS 2 decimal math problem

N3JQD

I have a BS2 and the Parallax FM receiver board. Everything works, but, I am attempting to program the frequency by use of the RCTIME command. I wish to dial in the frequency directly from the variable pot.
The problem is that I cannot input anything but whole numbers into the FM board. How would one go about inputting decimal values? i.e. 93.3 FM. I can use the sample program from Parallax, but, I want to experiment with 2 variable pots. One for freq. input and one for volume control. Volume is easy, no prob there. Tnx.

mw0868

If you have enough I/O pins left, perhaps you could try one of Parallax's rotary encoder products. Ticks in the clockwise direction could increment the frequency in steps, i.e 93.1, 93.3, 93.5, etc. CCW steps could decrement frequency. You could wrap-around when you reached a frequency limit.

Mike Green

To use a pot for frequency, you'll have to use units of 100KHz, so your frequency values are 880, 881, ... , 1079. You'd subtract 880 from this to get a range of 0 to 199. You'll have to refer to the documentation on RCTIME to figure out what pot value (and series resistor for the minimum resistance) you'll need to get a range of 200 values. You could also use a larger range of RCTIME values and transform that with subtraction of the base value then division by some constant to get a range of 0 to 199.

N3JQD

OK, thanks for the suggestions. Sounds good.