Table too slow?

[stan cartwright]

I have stepper motor code that works using case but not reading from a table.
When I use case the program works and the motors do as told but when using a table they just go in one direction.
The motor control is 100Hz interrupt. Is reading table too slow for interrupt or is there an error in my prog.
This snip works but uncomment ReadTable lmot,lmotor,lmotval and comment select case lmotor to End select doesn't. They should do the same but is the 100Hz interrupt to short?

;  ReadTable lmot,lmotor,lmotval
    select case lmotor
      case 1
      lmotval=128
      case 2
      lmotval=192
      case 3
      lmotval=64
      case 4
      lmotval=96
      case 5
      lmotval=32
      case 6
      lmotval=48
      case 7
      lmotval=16
      case 8
      lmotval=144
    End Select
;
table lmot
128,192,64,96,32,48,16,144
end table

The complete program that works as is but not if table is used.

;328p nano controlling two 28BYJ-48 Stepper Motors using interrupt
#chip mega328p,16
#option Explicit
dir portb out
dir portd out

dim lmotdir,lmotor,rmotdir,rmotor,lmotval,rmotval as byte
lmotdir=255:lmotor=1:rmotdir=1:rmotor=1

;interrupt drives motor 100 Hz
    On Interrupt Timer0Match1 Call motors

    Dim OCR0  AS byte alias OCR0A
    Dim TCCR0 AS  byte alias TCCR0B
    WGM01 = 1                'Timer in CTC mode - required

    OCR0 = 19
    TCCR0 = 0x28
    TCCR0 = TCCR0 or 0x05

;

do ; move motors
lmotdir=255:rmotdir=255
wait 2 s
lmotdir=1:rmotdir=255
wait 2 s
lmotdir=255:rmotdir=1
wait 2 s
lmotdir=1:rmotdir=1
wait 2 s
loop
;----- end

Sub motors ;This will be called when the Timer overflows
;left stepper motor
  if lmotdir>0 then
    if lmotdir=1 Then
      lmotor++
      if lmotor=9 then lmotor=1
    else
      lmotor---
      if lmotor=0 then lmotor=8
    end if
  ;
;  ReadTable lmot,lmotor,lmotval
    select case lmotor
      case 1
      lmotval=128
      case 2
      lmotval=192
      case 3
      lmotval=64
      case 4
      lmotval=96
      case 5
      lmotval=32
      case 6
      lmotval=48
      case 7
      lmotval=16
      case 8
      lmotval=144
    End Select
  Else
    lmotval=0
  end if
;right stepper motor
  if rmotdir>0 then
    if rmotdir=1 Then
      rmotor++
      if rmotor=9 then rmotor=1
    else
      rmotor---
      if rmotor=0 then rmotor=8
    end if
  ;
;    ReadTable rmot,rmotor,rmotval
    select case rmotor
      case 1
      rmotval=1
      case 2
      rmotval=3
      case 3
      rmotval=2
      case 4
      rmotval=6
      case 5
      rmotval=4
      case 6
      rmotval=12
      case 7
      rmotval=8
      case 8
      rmotval=9
    End Select
  else
    rmotval=0
  end if

  portd=(portd and 15)+lmotval
  portb=(portb and 240)+rmotval

End Sub
;
table lmot
128,192,64,96,32,48,16,144
end table
;
table rmot
1,3,2,6,4,12,8,9
end table

[stan cartwright]

For some reason it works now. I rebuilt the mcp23017 stepper driver and it's fine, instead of case I read from a table..looks neater. Can't work out why

[stan cartwright]

I take it back! Using a table for 28BYJ-48 Stepper Motor with ULN2003a driver is iffy.
This code works and moves the motors but if I uncomment the readtable and comment select case to end select, the motors just go in one direction.(there's a band called that)
annoying me. read table should do the same as case.
Using one table makes both motors just go in one direction.
Working using case https://youtu.be/jxKymWoiZ2k

#chip mega328p,16
#include <MCP23017.h>
#option Explicit
   #define I2C_MODE Master
   #define I2C_DATA PORTC.4
   #define I2C_CLOCK PORTC.5
   #define I2C_DISABLE_INTERRUPTS ON
   'Optionally, you can reduce the I2C timings.
   #define I2C_BIT_DELAY 0 us
   #define I2C_CLOCK_DELAY 1 us
   #define I2C_END_DELAY 0 us

#define MCP23017_addr 0x4e
;#define MCP23017_IODIRA 0; make porta output
MCP23017_sendbyte (MCP23017_addr,MCP23017_IODIRA,0)
dim lmotdir,lmotor,rmotdir,rmotor,lmotval,rmotval as byte
lmotdir=1:lmotor=1:rmotdir=1:rmotor=1

dir portb.0 out ;scope

;interrupt drives motors
    On Interrupt Timer1Overflow Call motors
    ' Initialise the timer - this is required
    ' Set prescaler to 1 and then start the timer
    InitTimer1 Osc, PS_1_1
    ' Start the timer - this is required
    StartTimer 1

    SetTimer 1, 40000
;
;-------------------------
;
MCP23017_sendbyte( MCP23017_addr,MCP23017_GPIOA,0) ;set port a to out
wait 1 s
;
do
lmotdir=255:rmotdir=255
wait 2 s
lmotdir=1:rmotdir=1
wait 2 s
lmotdir=0:rmotdir=0
wait 1 s
lmotdir=255:rmotdir=1
wait 2 s
lmotdir=0:rmotdir=0
wait 1 s
lmotdir=1:rmotdir=255
wait 2 s
loop
;----- end
'This will be called when the Timer overflows
Sub motors

  SetTimer 1, 40000 ;reset timer faster

 ;left stepper motor
  if lmotdir>0 then
    if lmotdir=1 Then
      lmotor++
      if lmotor=9 then lmotor=1
    else
      lmotor---
      if lmotor=0 then lmotor=8
    end if
;  ReadTable lmot,lmotor,lmotval
    select case lmotor
      case 1
      lmotval=128
      case 2
      lmotval=192
      case 3
      lmotval=64
      case 4
      lmotval=96
      case 5
      lmotval=32
      case 6
      lmotval=48
      case 7
      lmotval=16
      case 8
      lmotval=144
    End Select
  Else
    lmotval=0
  end if
;right stepper motor
  if rmotdir>0 then
    if rmotdir=1 Then
      rmotor++
      if rmotor=9 then rmotor=1
    else
      rmotor---
      if rmotor=0 then rmotor=8
    end if
;    ReadTable rmot,rmotor,rmotval
    select case rmotor
      case 1
      rmotval=1
      case 2
      rmotval=3
      case 3
      rmotval=2
      case 4
      rmotval=6
      case 5
      rmotval=4
      case 6
      rmotval=12
      case 7
      rmotval=8
      case 8
      rmotval=9
    End Select
  else
    rmotval=0
  end if
  portb.0=!portb.0 ;scope pin
  MCP23017_sendbyte (MCP23017_addr,MCP23017_GPIOA,lmotval+rmotval) ;sets porta to lmotval+rmotval
End Sub
;
table lmot
128,192,64,96,32,48,16,144
end table
;
table rmot
1,3,2,6,4,12,8,9
end table

[mmotte]

Stan,

I see your playing with a 28BYJ-48 Stepper.

So was I about a year ago. It needed to be minature so i used a 12f683. This worked real slick for positioning a magic trick. Maybe you can get some ideas off of this?

'A program to Run a 4096 step geared step motor 28BYJ-48
'actually this is doing full step mode in which 2 coils are active at a Time
' so it only has 2048 steps/turn (seems like a couple less)
'Another array could be built to do eight half steps
'The outputs run a ULN2003 like supplied by so many chinese suppliers
'The input Port GPIO.4 has a pushbutton
'Setup: routine allows the operator to align the shaft on start up
'MainLoop: routine rotates the motor one full turn
'If you change the MainLoop in line 41 to MainLoop2 then it
'will demo a 5 station/position pattern
'by Mike Otte
'2013 ,,,upgraded  2016

'Chip model
#chip 12F683, 8

  dim Full(5)
      Full(0) = b'00000110'
      Full(1) = b'00000011'
      Full(2) = b'00001001'
      Full(3) = b'00001100'

'Set the pin directions
dir GPIO.0 out  'These are  wired to the uln2003 inputs
dir GPIO.1 out
dir GPIO.2 out
dir GPIO.5 out

dir GPIO.4 IN   'pushbutton input

Dim position as Word  'Could be integer if we go below 0 position
position =0

'Main routine
Setup:
  If GPIO.4 = 1 Then StepCW

  If GPIO.4 = 0 Then
    position =0
    wait 500 ms
    goto MainLoop ' to demo 5 position
  end if
  goto Setup

'One turn MainLoop ,get here from 3 lines above ,line41
MainLoop:
  If GPIO.4 = 1 Then goto MainLoop

  StepTo(2040)  'one turn

  position =0   'resets position counter for next move
  wait 500 ms   'Gives time for button release if only a few steps

 goto MainLoop

' Example of going to 5 different positions and waiting for the button to be pushed
'Button is a pull down
MainLoop2:
  If GPIO.4 = 1 Then goto MainLoop2
  If GPIO.4 = 0 Then
    station++
    If station > 5 then station = 1

    wait 500 ms
    goto newstation
  end if
  goto MainLoop2
newstation:
  Select case station
    case 1
        StepTo(500) 'station position 1
        wait 500 ms   'Gives time for button release if only a few steps
    case 2
        StepTo(1500)  'station position 2
        wait 500 ms   'Gives time for button release if only a few steps
    case 3
        StepTo(2500)  'station position 3
        wait 500 ms   'Gives time for button release if only a few steps
    case 4
        StepTo(3000)  'station position 4
        wait 500 ms   'Gives time for button release if only a few steps
    case 5
        StepTo(3100)  'station position 5
        wait 500 ms   'Gives time for button release if only a few steps
    end Select
 goto MainLoop2

Sub StepTo(newpos as word)
    EnMotor
   Do until Position = newpos
    If newpos < position then StepCCW

    If newpos > position then StepCW

   loop
   DisEnMotor
end sub

Sub EnMotor
  dir GPIO.0 out
  dir GPIO.1 out
  dir GPIO.2 out
  dir GPIO.5 out
end sub

Sub DisEnMotor
  dir GPIO.0 in 'disables motor so it converves energy and don't heat up
  dir GPIO.1 in
  dir GPIO.2 in
  dir GPIO.5 in
end sub

Sub StepCW
    Position++
    myStep = position mod 4
    thisStep = Full(myStep)
    GPIO.0 = thisStep.0
    GPIO.1 = thisStep.1
    GPIO.2 = thisStep.2
    GPIO.5 = thisStep.3
    wait 2 ms
end sub

Sub StepCCW
    Position--
    myStep = position mod 4
    thisStep = Full(myStep)
    GPIO.0 = thisStep.0
    GPIO.1 = thisStep.1
    GPIO.2 = thisStep.2
    GPIO.5 = thisStep.3
    wait 2 ms
end sub

End

BR
73
Mike

[stan cartwright]

You turn off motor with gpio in, I just set motor lines to 0.
My code works fine using case but read table,the same values and motors don't change direction or stop. So obvious I can't see the wood for trees thing.
The motors are carp but cheap and for a "robot" cheaper than geared dc motor and h-bridge.
Data sheet says run at 100Hz but I'm rubbish at interrupt calc so used a scope to test portb.0=!portb.0 so guess frequency is half shown.
I'm using as uni-polar but there's another way I saw that doesn't use the common,the guy cut tracks on the motor but a reply said not necessary.
For a "table top robot" I can change motor speeds with interrupt freq or turn intoff and single step.
Not a "real" steppper but interesting. Cheers.

[stan cartwright]

Interesting Mike you wait 2 ms between next phase. I marked the wheels and 4096 phases give one revolution. I changed it to 1 ms and it doesn't go 360 deg ??
ps I tried
Full(0) = b'00000110'
Full(1) = b'00000011'
Full(2) = b'00001001'
Full(3) = b'00001100'
but seemed familiar and didn't work ie motors buzzed not move. The phase pattern that is

[stan cartwright]

I also tried an array but the motors didn't even move. I'll stick with case that works fine, just annoying I can't see my error.

'dim lmotvalph(8) as byte
'lmotvalph(1)=b'10000000
'lmotvalph(2)=b'11000000
'lmotvalph(3)=b'01000000
'lmotvalph(4)=b'01100000
'lmotvalph(5)=b'00100000
'lmotvalph(6)=b'00110000
'lmotvalph(7)=b'00010000
'lmotvalph(8)=b'10010000
'
'dim rmotvalph(8) as byte
'rmotvalph(1)=b'00000001
'rmotvalph(2)=b'00000011
'rmotvalph(3)=b'00000010
'rmotvalph(4)=b'00000110
'rmotvalph(5)=b'00000100
'rmotvalph(6)=b'00001100
'rmotvalph(7)=b'00001000
'rmotvalph(8)=b'00001001

;lmotval=lmotvalph(lmotor)
;rmotval=rmotvalph(rmotor)

[stan cartwright]

This is getting silly. Why don't bin vals work ie use bin vals in prog instead of decimal?
These little motors work fine with case.

   select case lmotor
      case 1
      lmotval=128 ;b'10000000 ;128
      case 2
      lmotval=192 ;b'11000000 ;192
      case 3
      lmotval=64 ;b'01000000 ;64
      case 4
      lmotval=96 ;b'01100000 ;96
      case 5
      lmotval=32 ;b'00100000 ;32
      case 6
      lmotval=48 ;b'00110000 ;48
      case 7
      lmotval=16 ;b'00010000 ;16
      case 8
      lmotval=144 ;b'10010000 ;144
    End Select