Multiple IF THEN Statements: PIC16F84A

[bob425]

Forum Members:

I am using PicBasisPro Ver 2.50a, Melabs Programmer Ver. 4.40 and MicroCode Studio Ver. 2.0.0.5 for the following PIC16F84A application.

Even though I have used both the Melabs printer port of the Melabs USB programmers I haven't identified the following problem.

1. Go to the LOOP section.
2. The first IF THEN performs as intended.
3. The second IF THEN does not even execute the "GOSUB pwrup" sub-routine.
4. If I reverse the IF THEN codes, the first IF THEN section always executes.

I’ve read the PIC16F84A data sheet and haven’t found, or have overlooked, any constants of using the following code on the PIC16F84A component.

Perhaps I’m “too close to the trees…”

Any assistance will be appreciated.

Regards,

Bob

==================================================================
'********************************************************************
'*  Name : Syn-Ren50.BAS            Author  : Bob Wills              *
'*  MCU  : PIC 16F84A               USE     : OLIN FOX LIFT          *
'*  Date : 08/04/2012, Ver. 2.0     PicBasic Pro Compiler            *
'*  Words: 712                      Duty Cycle:   ~ 0.79 step/1%DC   * 
'*  NOTE: This program controls a BDC motor to move a lift up/down   *
'*  with the following features:                                     *
'*  1. Increase the motor speed (up/down) from stop to running speed.*
'*  2. Decrease the motor speed (up/down) just before the stopping   *
'*     limit switch.                                                 *
'*  3. Provide various stopping rates for safety purposes.           *
'*  4. The motor is controlled by a Dimension Engineering            *
'*     Single Channel 50A continuous/100A peak, Brushed motor        *
'*     controller, Model: SyRen50.  This contoller containa a MCU.   *
'*  5. A PIC16F84A interfaces between the lift inputs and the SyRen50 *
'*     and sends control signals to the SyRen50 using the PBP        *
'*     "SEROUT" statement -- SEROUT mtrdat, T2400, [n]               *
'*  6. SEROUT mtrdat, T9600, [127] = motor stop,                     *
'*     ...[0] = motor full reverse; ...[255] = motor full forward.   *
'*********************************************************************
@ DEVICE PIC16F84A, XT_OSC  ' 4Mhz
@ DEVICE PIC16F84A, WDT_OFF ' Watchdog Timer
@ DEVICE PIC16F84A, PWRT_ON ' Power-On Timer
@ DEVICE PIC16F84A, PROTECT_OFF ' Program Code Protection

stdwnv          con    109      'range 127-0: 96~6vdc, 64~12vdc 
stupv           con    145      'range 127-256: 158~6vdc, 190~12vdc
upstps          con     30      'up
dwnstps         con     30      'down
sloup           con     30      'up end speed
slodwn          con     30      'down end speed
i               var     byte
n               var     BYTE
upv             var     byte
dwnv            var     byte
                       'pin
sss         VAR PORTA.0           'Pin 17  'RA0/AN0                input safety switch
slo         VAR PORTA.1           'Pin 18  'RA1/AN1                input for slow interrupt
upstp       VAR PORTA.2         'Pin  1    'RA2/AN2/CVREF/VREF-    input for up stop
dwnstp      VAR PORTA.3        'Pin  2    'RA3/AN3/VREF+/C1OUT    input for down stop    
'           VAR PORTA.4            'Pin  3    'RA4/AN4/T0CKI/C2OUT    recvr input = down start        
'                                         Pin 4            MCLR
'                                         Pin 15           OSC2/CLKOUT
'                                         Pin 16           OSC1/CLKIN

syrenpwr    VAR PORTB.0        'Pin   6   'RB0/INT/CCP1   output to the syren power relay
mtrlp       VAR PORTB.1           'Pin  7   'RB1/SDI/SDA    output to the motor loop relay
mtrdat      VAR PORTB.2          'Pin  8   'RB2/SDO/RX/DT  output data control for syrenpwr 
'           VAR PORTB.3             'Pin  9   'RB3/PGM/CCP1            
rkrup       VAR PORTB.4           'Pin 10   'RB4/SCK/SCL    rocker input for up start   
rcvrdn      VAR PORTB.5          'Pin 11   'RB5/SS/TX/CK   receiver input for down start 
rcvrup      VAR PORTB.6          'Pin 12   'RB6/AN5/PGC/T1OSO/T1CKI ICSP CLOCK 
                                          'rcvr input for up start
'              VAR PORTB.7          'Pin 13   'RB7/AN6(6)/PGD/T1OSI   ICSP DATA Manual Switch

PORTA = 5               'PORTA MEMORY ADDRESS
TRISA = 133             'TRISA MEMORY ADDRESS
TRISA = %11111111  		'SET PORTA DATA DIRECTIONS
PORTA = %00000000       'CLEAR PORTA MEMORY

PORTB = 6               'PORTB MEMORY ADDRESS
TRISB = 134             'TRISB MEMORY ADDRESS             
TRISB = %11111000       'SET PORTB DATA DIRECTIONS        
PORTB = %00000000       'CLEAR PORTB MEMORY
INCLUDE "modedefs.bas" 


'--------------------------------------------------------------------------   
loop: 
   
    if (rcvrup = 0) and (upstp = 1) then
    gosub pwrup
    gosub uprcvr
    else
    gosub pwrdwn
    endif
     
    if (rcvrdn = 0) and (dwnstp = 1) then
    gosub pwrup
    gosub dwnrcvr
    else
    gosub pwrdwn
    endif
 
 gosub loop
'--------------------------------------------------------------------------
dwnrcvr:             'Increases motor speed from stop to "up speed rate'
                          
    serout mtrdat, T2400, [stdwnv] 
    pause 1000
    dwnv = stdwnv
    pause 50                                                           
    for i = 1 to dwnstps step 1
    dwnv = dwnv - 1 
    SEROUT mtrdat, T2400, [dwnv]
    pause 50
       if (rcvrdn = 1) oR (dwnstp = 0)  then   'stop & limit sw
       serout mtrdat, T2400, [127]
       gosub pwrdwn
       else
       endif
    next i
    pause 1000
    gosub loop
 '--------------------------------------------------------------------------
uprcvr:             'Increases motor speed from stop to "up speed rate'
 
    serout mtrdat, T2400, [stupv] 
    pause 1000
    upv = stupv
    pause 50                                                           
    for i = 1 to upstps step 1
    upv = upv + 1 
    SEROUT mtrdat, T2400, [upv]
    pause 50
       if (rcvrup = 1) oR (upstp = 0)  then   'stop & limit sw
       serout mtrdat, T2400, [127]
       gosub pwrdwn
       else
       endif
    next i
    pause 1000
    gosub loop
'--------------------------------------------------------------------------
pwrup:
    high syrenpwr
    pause 500
    serout mtrdat, T2400, [127]
    pause 250
    high mtrlp
return
'--------------------------------------------------------------------------
pwrdwn:
        serout mtrdat, T2400,[127]
        pause 50
        low syrenpwr                 
        pause 10 
        low mtrlp
        gosub loop 
'--------------------------------------------------------------------------