code problem

mikea · 2013-02-07 16:17

The following will ramp up a led until i added the "repeat while ina[1]==1. I,ve spent a lot of time and i'm still stumped. In the future i want 2 buttons to ramp up/down a dc motor, but i'm stuck here. thanks for any help.-mike

CON
_clkmode = xtal1 + pll16x ' System clock &#8594; 80 MHz
_xinfreq = 5_000_000
PUB TestPwm | tC, tHa, t
ctra[30..26] := %00100 ' Configure Counter A to NCO
ctra[5..0] := 4
frqa := 1
dira[4]~~   'pin for led
dira[1]~
tHa:=1
tC := 10000 ' Set up cycle and high times
t := cnt ' Mark counter time 
repeat
   repeat while ina[1]==1   'pushbutton held down
     
      phsa := -tHa ' Set up the pulse
      ++tHa
      t += tC ' Calculate next cycle repeat
      waitcnt(t) ' Wait for next cycle

Ariba · 2013-02-07 17:39

Here is an untested code that ramps up and down with two buttons. It also makes sure hat the PWM value is always inside 0..10000.

CON
_clkmode = xtal1 + pll16x ' System clock &#8594; 80 MHz
_xinfreq = 5_000_000

 UP    = 1  'button pins
 DOWN  = 2
 SPEED = 1  '1=slow .. ~100=fast

PUB TestPwm | tC, tHa, t
 ctra[30..26] := %00100 ' Configure Counter A to NCO
 ctra[5..0] := 4
 frqa := 1
 dira[4]~~   'pin for led = output
 tHa:=1
 tC := 10000 ' Set up cycle and high times
 t := cnt ' Mark counter time 
 repeat
    phsa := -tHa ' Set up the pulse
    if ina[UP]==1 and tHa < 10000
       tHa += SPEED
    if ina[DOWN]==1 and tHa > 0
       tHa -= SPEED
    t += tC ' Calculate next cycle repeat
    waitcnt(t) ' Wait for next cycle
'

Andy

code problem

Comments