Square wave generation

Elkin

I am pretty sure this is possible but I just cant seem to figure out how to do it.

I am trying to generate a 512 kHz square wave signal. My prop is running at 80 MHz and I have read appnote001 that I also attached here, but I cant seem to get any output from any pin on the propeller. I am trying to run a transistor which is driving a PAL system clock.

My guess is that it has something to do with this PLLDIV and the cog counters but I am just not sure how to put this together.

Thanks!

kuroneko

Let's settle for an NCO. See if this works for you.

CON
  _clkmode = XTAL1|PLL16X
  _xinfreq = 5_000_000
  
CON
  pin = 16
  
PUB null

  dira[pin]~~
  ctra := constant(%0_00100_000 << 23 | pin)            ' NCO
  frqa := $01A36E2E

' frqx := [COLOR="orange"]512k[/COLOR]*2^32/clkfreq

  waitpne(0, 0, 0)
  
DAT

Note that this doesn't quite generate 512kHz but it looks close enough to me (511999.987Hz). Using frqa := $01A36E2F would give you 512000.005Hz.

Elkin

That looks good, I figured it was something easy like that. Thanks for your help!