Matlab to PWMPAL Serial Communication

SChid

I am trying to send information from a simulink program with an embedded matlab code to my basic stamp which is working with a PWMPAL to control the direction and speed of a winch motor. I can't seem to get the serial communication to work. I download the PBASIC coding and then I try running my simulink/matlab program and nothing happens. The PWMPAL code was adapted from a motor control example presented by Parallax and it works. Help please.

PWMPAL Code

' {$STAMP BS2}
' {$PBASIC 2.5}
'
'***********************************************************************************************************
'

---

I/O Definitions

---

PpPin···· PIN······· 0·········· 'PWMPAL Serial I/O
DirCtrl·· PIN······· 2·········· 'Direction I/O
Rx······· PIN······· 14········· 'Serial I/O Pin
'

---

Constants

---

MotorNum· CON······· 1
'SELECTED STAMP BS2
T9600···· CON······· 84·········· 'BaudRate 9600
T19K2···· CON······· 32·········· 'BaudRate 19200
T38K4···· CON······· 6··········· 'BaudRate 38400
PpBaud··· CON······· T9600
OUT······ CON······· 0
IN······· CON······· 1
MinSpeed· CON······· 1·········· 'minimum DC to spin Winch Motor
'SERIAL COM
N9600···· CON······· $4054······ 'Baud mode value for 9600 baud, 8,N,1
'

---

Variables

---

speed···· VAR······· Word···· 'speed, 0% to 100%
status··· VAR······· Byte···· 'motor control status
direction VAR······· Word···· 'Motor Direction

onTime··· VAR······· Word···· 'PWM timing
offTime·· VAR······· Word
'

---

Receive Serial Info

---

DO
Receive:
· SERIN Rx,N9600, [noparse][[/noparse]speed.BYTE1, speed.BYTE0, direction.BYTE1, direction.BYTE0]
'

---

Program Code

---

Main:
··· IF (direction = OUT) THEN
····· HIGH DirCtrl
··· ELSE
····· LOW DirCtrl
··· ENDIF
··· 'IF (speed < 100) THEN
····· 'speed = speed + MinSpeed
····· 'PAUSE 100
··· IF (speed < 5) THEN
····· speed = 0
··· ENDIF
··· IF (speed > 100) THEN
····· speed = 100
··· ENDIF
··· GOSUB Speed_Ctrl

··· DEBUG CR, "Speed = ", DEC speed, CLREOL
··· DEBUG HOME, "Direction: ", direction, CLREOL
LOOP

'

---

Subroutines

---

Speed_Ctrl:
· onTime = speed
· offTime = 100 - speed···· 'Set duty cycle
· SEROUT PpPin, PpBaud, [noparse][[/noparse]"!PWMM", (48 + MotorNum), onTime.BYTE0, onTime.BYTE1, offTime.BYTE0, offTime.BYTE1]
· 'status.HIGHNIB = %0001 << (MotorNum - 1)········ 'Set enable bit
· 'status.LOWNIB = %0001 << (MotorNum - 1)········· 'Set control bit
· 'SEROUT PpPin, PpBaud, [noparse][[/noparse]"!PWMSS", status]
· RETURN
· '**********************************************************************************************************

Matlab Code


velocity=test;

if (velocity < 0.0);

vel_dir = 1;

else

vel_dir = 0;

end

MAX_V = 0.2;

vel_perc = abs(velocity)/MAX_V;

s = serial('COM1');

set(s, 'BaudRate', 9600);

fopen(s);

fprintf(s, '%d\n', vel_dir);

fprintf(s, '%f\n', vel_perc);

fclose(s);


·

Franklin

Try working on the communications first. Take the rest of the code out and just send and receive code to make a pin high or low and attach an LED to tell when it works.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
- Stephen