assembly call

10gigbill

New @ assembly... I want to have cogs putting out square waves at two freqs, and do something else in spin... also would like to have
an assembly routine I could call to just put out a short pulse (<1Us)
see code... not working...
Thanks...

Ariba

You need another ORG 0 just before the Tweet label. The code for the second cog needs also to be compiled from addr 0.

Andy

JonnyMac

Remember that you can use a counter to output a short pulse -- this way you don't have to launch a cog

pub pulse_out(pin, tix) | mask

  mask := |<pin

  ctra := (%00100 << 26) | pin                                  ' configure for pulse
  frqa := 1
  dira[pin] := 1

  phsa := -tix                                                  ' start pulse
  waitpeq(mask, mask, 0)                                        ' wait for high
  wanipne(mask, mask, 0)                                        ' wait for low

  ctra := 0                                                     ' kill counter

Warning... if the pulse is VERY short, the waitpeq may get missed -- you'll need to test. You can also port this code to PASM; there is nearly a 1-for-1 instruction match.

10gigbill

Thanks Andy , that fixed it... And Thanks Jon. I'll work on your sample tomorrow..
good job guys...

Bill

10gigbill

And one more... how do I call an assembly routine.. see what I added...?

JonnyMac

To communicate with your assembly routine you have to pass the hub address of a "mailbox" variable. I made a really simple pulse generator app (that's all it does) so you can see how this works.

The second parameter of cognew() is the hub address that is your mailbox. Since this address is passed to the cog, you can use it as a base address for several values. In this demo, there is only one (ticks). Note that when the pulse is done the cog tells the Spin program it's finished by clearing the ticks pulse timing.