Streamer->DAC: what am I doing wrong? [solved]

pik33 · 2021-02-21 13:25

I am trying to get something i can hear on pins 0-4 using the streamer (in this case this should be a square wave). What am I doing wrong?

CON

base      = 0
_clkfreq  = 200_000000

pub test1()

coginit(0,@a_test, 0)


DAT             org

a_test          drvl    #4<<6 + base                         'Drive 4 pins starting from base LOW
                wrpin   dac75,#4<<6 + base                   'Set DACs @ 2V/75 Ohm

                setxfrq a80000000                            'set streamer freq to 1:1

                '' i want the streamer to output SOMETHING on pin 0..3

p103            mov ii,#10
p101            xcont m_test, #0
                djnz ii,#p101
                mov ii,#10
p102            xcont m_test, affffffff
                djnz ii,#p102
                jmp #p103


dac75           long    %0000_0000_000_1011100000000_01_00000_0                          '75-ohm, 2.0V
m_test          long    %0111_1111_1000_0001_0000_0000_0000_0000 + base<<17 + 65535      'imm->4xDAC
affffffff       long    $FFFFFFFF
a80000000       long    $80000000
ii              res     1

pik33 · 2021-02-21 14:09

Solved. First wrpin, then drvl.

Edit: Yet another beginner's error. Use #3, not #4, to set 4 pins.

a_test           wrpin   dac75,#3<<6 + base                   'Set DACs @ 2V/75 Ohm
                 drvl    #3<<6 + base                         'Drive 4 pins starting from base LOW

evanh · 2021-02-21 14:17

Right, some modes need DIR low during init or they just don't start up sensibly. So the full sequence is FLTL then WRPIN/WXPIN then DIRH. Others aren't so fussy.

Streamer->DAC: what am I doing wrong? [solved]

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