Synchronous pulses

[Mike, K8LH]

Hey Andrew,

Once I figure out how to force an address for the toggle array in Swordfish BASIC I suspect my method might look something like this BASIC example, which I hope makes more sense than my previous pseudo C example.

Kind regards, Mike

Dim Tgl(1024) As Byte                   ' ??? force to $400..$7FF ???
Dim Pulse(3) As Word
Dim LastElement As FSR0H.booleans(3)
'
    Pulse(0) = 3                        ' RB0 pulse, 0..1023 usecs
    Pulse(1) = 11                       ' RB1 pulse, 0..1023 usecs
    Pulse(2) = 12                       ' RB2 pulse, 0..1023 usecs
'
'  clear the 1024 element toggle array
'
    FSR0 = AddressOf(Tgl)               ' indirect for Tgl(0)
    Repeat                              ' clear toggle array
        POSTINC0 = 0                    ' clear 0x400..0x7FF
    Until LastElement                   '
'
'  insert 3 output toggle bits into our 1024 interval toggle array
'
    Tgl(Pulse(0)) = Tgl(Pulse(0)) Or 1  ' insert RB0 toggle bit
    Tgl(Pulse(1)) = Tgl(Pulse(1)) Or 2  ' insert RB1 toggle bit
    Tgl(Pulse(2)) = Tgl(Pulse(2)) Or 4  ' insert RB2 toggle bit
    Tgl(0) = Tgl(0) Xor $FF             ' prep Tgl(0) element
'
'  implement a button press or some other trigger before falling into
'  the output routine (1024 1-usec intervals with 20-MHz clock)
'
    FSR0 = AddressOf(Tgl)               ' Tgl(0..1023), 0x400..0x7FF
    Repeat                              ' toggle outputs from toggle array
        LATB = LATB Xor POSTINC0        ' at 1-usec (5 cycle) intervals
    Until LastElement                   ' until end-of-array (0x800)