Litle Problem with OUTA[17..23]

Anubisbot · 2007-05-25 03:45

Hi , i still work on my PWM Object, and it works so far fine, but i tried to change mz spin so that only 8 pin will be used, and insted of a long i want to use a byte.

Here is the working code:

CON
  TableSize = 100

VAR
  
  ' Holds the value the output should take at each instant in time.
  long pwm_state[noparse][[/noparse]TableSize]
  long cogStack[noparse][[/noparse]30]

PUB Start | i                  
  SetPWM(17,100)
  SetPWM(18,0)
  SetPWM(16,0)
  SetPWM(19,0)
  waitcnt( 5_000 + cnt ) 
  coginit (3,pwm_loop,@cogStack)
  return 
PRI pwm_loop | t
  ' start the time value at zero
  ' PWM Loop
  dira[noparse][[/noparse]9] := 1                  ' Make pin 0, pin 1, and pin 2 all outputs
  dira[noparse][[/noparse]19] := 1
  dira[noparse][[/noparse]18] := 1
  dira[noparse][[/noparse]16] := 1
  dira[noparse][[/noparse]17] := 1

  t := 0
  repeat 
    outa := pwm_state[noparse][[/noparse]t]       ' Set states of all 3 pwm pins simultaneously
    t+ = 1                      ' Change to the next state
    if t == TableSize           ' If t goes off the edge of the table  NOTE change
      t := 0                    ' start over at beginning

and here is what i try to do but it wont work my way...

CON
  TableSize = 100

VAR
  
  ' Holds the value the output should take at each instant in time.
  byte pwm_state[noparse][[/noparse]TableSize]
  long cogStack[noparse][[/noparse]30]

PUB Start | i                  
  SetPWM(17,100)
  SetPWM(18,0)
  SetPWM(16,0)
  SetPWM(19,0)
  waitcnt( 5_000 + cnt ) 
  coginit (3,pwm_loop,@cogStack)
  return 
PRI pwm_loop | t
  ' start the time value at zero
  ' PWM Loop

  dira[noparse][[/noparse]23..17]~~

  t := 0
  repeat 
    outa[noparse][[/noparse]23..17] := pwm_state[noparse][[/noparse]t]' Set states of all 3 pwm pins simultaneously
    t+ = 1                      ' Change to the next state
    if t == TableSize           ' If t goes off the edge of the table  NOTE change
      t := 0                    ' start over at beginning

I dont get it.. What do i miss...
Anubisbot

Mike Green · 2007-05-25 03:52

1) dira[noparse][[/noparse]23..17] and outa[noparse][[/noparse]23..17] are both 7-bit values (which may be what you want) with I/O pin 23 the high order bit and I/O pin 17 the low order bit.

2) When you do "outa[noparse][[/noparse]23..17] := ...", you are assigning a 7-bit value (from %0000000 to %1111111) which would work fine except that your SetPWM routine assumes that you have a 32-bit value.

3) You could make this work by using "outa[noparse][[/noparse]23..17] := pwm_state[noparse][[/noparse] t ] >> 17"

4) Do remember that outa[noparse][[/noparse]23..17] and outa[noparse][[/noparse]17..23] are not the same. The bits are reversed in the second case.

Anubisbot · 2007-05-25 04:14

Cool, now i understand that, and how ut works..

Thank you for the fast help.. This Forum and their users are great.

Anubisbot

Litle Problem with OUTA[17..23]

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