I am making a wifi controlled "robot" for a school project, and i wanted to use this project as a starting point. It uses a modified linksys router to connect over wifi with a computer and the router sends any commands (left, right, forward or backwards) it recieves to a microcontroller, wich then drives the h-bridge.
In the project above the microcontroller used is a PIC16F628A, but instead of using a remote controlled car I build my own tank like robot that uses 2 engines, so i would like to use pwm to control it in the future and therefor I would like to rewrite the code so it will work on a PIC16f876 which has 2 pwm channels.
The original code does a couple of things:
it turn a red led on on powerup
when it revieves the alive message from the router it turn a green led on and the right led of
it now waits for commands (left, right, forward, backwards and the horn)
This is the original code for the PIC16F628A:
This code functioned perfectly, but ofcourse only on a PIC16F628A, i then converted it to the code below, but the problem was that instead of the green led turning on when it had recieved the alive message, the led that is only supposed to indicate a "right" signal goes on and stays on. This "right" led still functions as the led for a "right" signal as well, so it has a double function (wich is unwanted ofcourse).
This probebly happend because of my changes to the code, since i had to change all of the porta into portb and portb into portc. I also had to change the greenled to RC3 (it was originaly on portb), this should just work ofcourse but i most have missed one bit of code since the greenled shows on RB3 after recieving the "greeting" mesage from the router.
See my next post for the rest of the question, it was to long to post at once
In the project above the microcontroller used is a PIC16F628A, but instead of using a remote controlled car I build my own tank like robot that uses 2 engines, so i would like to use pwm to control it in the future and therefor I would like to rewrite the code so it will work on a PIC16f876 which has 2 pwm channels.
The original code does a couple of things:
it turn a red led on on powerup
when it revieves the alive message from the router it turn a green led on and the right led of
it now waits for commands (left, right, forward, backwards and the horn)
This is the original code for the PIC16F628A:
Code:
;*******************************************************************
; Function: Wifi Robot Controller
; Processor: pic16f628 at 4 MHz using internal RC oscillator
; Filename: car_pic.asm
; Author: Jon Bennett
; Website: www.jbprojects.net/projects/wifirobot
; Credit: Based on UART Test Program
; http://www.oz1bxm.dk/PIC/628uart.htm
;*******************************************************************
#define DEBUG 0
greenLED equ b'10000000' ;128,RB7
redLED equ b'01000000' ;64, RB6
horn equ b'00100000' ;32, RB5
right equ b'00001000' ;8, RA3
left equ b'00000100' ;4, RA2
back equ b'00000010' ;2, RA1
forward equ b'00000001' ;1 RA0
LIST P=16F628, R=DEC ; Use the pic16f628 and decimal system
#include "P16F628.INC" ; Include header file
__config _INTRC_OSC_NOCLKOUT & _LVP_OFF & _WDT_OFF & _PWRTE_ON & _BODEN_ON & _MCLRE_OFF
CBLOCK 0x20 ; Declare variable addresses starting at 0x20
dataL
in_char
temp
d1
d2
ENDC
ORG 0x000 ; Program starts at 0x000
;
; --------------------------------
; set ANALOG/DIGITAL INPUTS PORT A
; --------------------------------
;
movlw 7
movwf CMCON ; CMCON=7 set comperators off
;
; ----------------
; INITIALIZE PORTS
; ----------------
;
movlw b'00000000' ; set up portA
movwf PORTA
movlw b'00000100' ; RB2(TX)=1 others are 0
movwf PORTB
bsf STATUS,RP0 ; RAM PAGE 1
movlw 0x00
movwf TRISA ; portA all pins output
movlw b'00000010' ; RB1(RX)=input, others output
movwf TRISB
; ------------------------------------
; set BAUD RATE TO COMMUNICATE WITH PC
; ------------------------------------
; Boot Baud Rate = 9600, No Parity, 1 Stop Bit
;
movlw 0x19 ; 0x19=9600 bps (0x0C=19200 bps)
movwf SPBRG
movlw b'00100100' ; brgh = high (2)
movwf TXSTA ; enable Async Transmission, set brgh
bcf STATUS,RP0 ; RAM PAGE 0
movlw b'10010000' ; enable Async Reception
movwf RCSTA
;
; ------------------------------------
; PROVIDE A setTLING TIME FOR START UP
; ------------------------------------
;
clrf dataL
settle decfsz dataL,F
goto settle
movf RCREG,W
movf RCREG,W
movf RCREG,W ; flush receive buffer
;
; ---------
; MAIN LOOP
; ---------
;
clrf PORTA
movlw redLED
movwf PORTB
call message ; prints out a message if DEBUG is 1
call check_init ; wait for INIT message from WRT54GL
bsf PORTB,7
loop call receive_delay ; wait for a char
call add_green ;set greenLED on
call process_input ;make sure that forward and backward aren't both high! or that greenLED and redLED aren't both high! or that left and right aren't both high!
call send ; send the char
goto loop
process_input
; Make sure that Forward & Backward cannot be ON at the same time
; Make sure that Left & Right cannot be ON at the same time
; Output result to PORTB
MOVWF temp
BTFSC temp,0 ;//Execute next line if temp,0 is HIGH
BCF temp,1
BTFSC temp,2 ;//Execute next line if temp,2 is HIGH
BCF temp,3
BTFSC temp,6 ;//Execute next line if temp,6 is HIGH
BCF temp,7
MOVF temp,0
andlw b'00001111'
movwf PORTA
movf temp,0
andlw b'11110000'
movwf PORTB
movf temp,0
return
add_green
movwf temp
btfss temp,7 ;If greenLED is LOW execute next line
bsf temp,7
movf temp,0
return
;
; -------------------------------------------
; RECEIVE CHARACTER FROM RS232 AND STORE IN W
; -------------------------------------------
; This routine does not return until a character is received.
;
receive btfss PIR1,RCIF ; (5) check for received data
goto receive
data_received
movf RCREG,W ; save received data in W
return
check_init
; waits to receive 'jbpro' from the router meaning that the software is up and running
; after the message is received, the greenLED is turned on and microcontroller can drive the car
call receive_delay
sublw 'j'
btfss STATUS, Z
goto check_init
call receive_delay
sublw 'b'
btfss STATUS, Z
goto check_init
call receive_delay
sublw 'p'
btfss STATUS, Z
goto check_init
call receive_delay
sublw 'r'
btfss STATUS, Z
goto check_init
call receive_delay
sublw 'o'
btfss STATUS, Z
goto check_init
#if DEBUG
;prints message and goes in to an endless loop of flashing greenLED
call message
Loop
; movlw greenLED
movlw 0xff
movwf PORTA ;set all bits on
call Delay ;this waits for a while!
movlw 0x00
movwf PORTA
call Delay
goto Loop ;go back and do it again
#endif
return
receive_delay
;299993 cycles
movlw 0x5E
movwf d1
movlw 0xEB
movwf d2
delay_0
btfsc PIR1,RCIF ;check for serial data
goto got_data ;if we do, goto got_data!
decfsz d1, f
goto $+2
decfsz d2, f
goto delay_0
movlw 0x00
return
got_data ;move data in to W
btfsc PIR1,RCIF
movf RCREG,W
return
#if DEBUG
Delay movlw d'250' ;delay 250 ms (4 MHz clock)
movwf temp
d11 movlw 0xC7
movwf d1
movlw 0x01
movwf d2
Delay_0
decfsz d1, f
goto $+2
decfsz d2, f
goto Delay_0
decfsz temp ,f
goto d11
retlw 0x00
#endif
;
; -------------------------------------------------------------
; SEND CHARACTER IN W VIA RS232 AND WAIT UNTIL FINISHED SENDING
; -------------------------------------------------------------
;
send
#if DEBUG
movwf TXREG ; send data in W
TransWt bsf STATUS,RP0 ; RAM PAGE 1
WtHere btfss TXSTA,TRMT ; (1) transmission is complete if hi
goto WtHere
bcf STATUS,RP0 ; RAM PAGE 0
#endif
return
;
; -------
; MESSAGE
; -------
;
message
#if DEBUG
movlw '1'
call send
movlw '6'
call send
movlw 'F'
call send
movlw '6'
call send
movlw '2'
call send
movlw '8'
call send
movlw ' '
call send
movlw 'a'
call send
movlw 'l'
call send
movlw 'i'
call send
movlw 'v'
call send
movlw 'e'
call send
movlw 0x0D ; CR
call send
movlw 0x0A ; LF
call send
#endif
return
ENDThis code functioned perfectly, but ofcourse only on a PIC16F628A, i then converted it to the code below, but the problem was that instead of the green led turning on when it had recieved the alive message, the led that is only supposed to indicate a "right" signal goes on and stays on. This "right" led still functions as the led for a "right" signal as well, so it has a double function (wich is unwanted ofcourse).
This probebly happend because of my changes to the code, since i had to change all of the porta into portb and portb into portc. I also had to change the greenled to RC3 (it was originaly on portb), this should just work ofcourse but i most have missed one bit of code since the greenled shows on RB3 after recieving the "greeting" mesage from the router.
Code:
#define DEBUG 0
greenLED equ b'00001000' ;128,RC3
redLED equ b'00010000' ;64, RC4
horn equ b'00100000' ;32, RC5
right equ b'00001000' ;8, RB3
left equ b'00000100' ;4, RB2
back equ b'00000010' ;2, RB1
forward equ b'00000001' ;1 RB0
; 16F876 PWM example code
;
; Device 16F876
LIST p=16F876
include "P16F876.inc"
__CONFIG _BODEN_ON & _CP_OFF & _CPD_OFF & _PWRTE_ON & _WDT_OFF & _LVP_OFF & _HS_OSC
CBLOCK 0x20 ; Declare variable addresses starting at 0x20
dataL
in_char
temp
d1
d2
ENDC
ORG 0x000 ; Program starts at 0x000
;
; --------------------------------
; set ANALOG/DIGITAL INPUTS PORT A
; --------------------------------
;
BANKSEL ADCON1
movlw 0x06
movwf ADCON1
BANKSEL PORTA
;
; ----------------
; INITIALIZE PORTS
; ----------------
;
movlw b'00000000' ; set up portB
movwf PORTB
movlw b'01000000' ; RC6(TX)=1 others are 0
movwf PORTC
bsf STATUS,RP0 ; RAM PAGE 1
movlw 0x00
movwf TRISB ; portB all pins output
movlw b'10000000' ; RC7(RX)=input, others output
movwf TRISC
; ------------------------------------
; set BAUD RATE TO COMMUNICATE WITH PC
; ------------------------------------
; Boot Baud Rate = 9600, No Parity, 1 Stop Bit
;
movlw 0x19 ; 0x19=9600 bps (0x0C=19200 bps)
movwf SPBRG
movlw b'00100100' ; brgh = high (2)
movwf TXSTA ; enable Async Transmission, set brgh
bcf STATUS,RP0 ; RAM PAGE 0
movlw b'10010000' ; enable Async Reception
movwf RCSTA
;
; ------------------------------------
; PROVIDE A setTLING TIME FOR START UP
; ------------------------------------
;
clrf dataL
settle decfsz dataL,F
goto settle
movf RCREG,W
movf RCREG,W
movf RCREG,W ; flush receive buffer
;
; ---------
; MAIN LOOP
; ---------
;
clrf PORTB
movlw redLED
movwf PORTC
call message ; prints out a message if DEBUG is 1
call check_init ; wait for INIT message from WRT54GL
bsf PORTC,3
loop call receive_delay ; wait for a char
call add_green ;set greenLED on
call process_input ;make sure that forward and backward aren't both high! or that greenLED and redLED aren't both high! or that left and right aren't both high!
call send ; send the char
goto loop
process_input
; Make sure that Forward & Backward cannot be ON at the same time
; Make sure that Left & Right cannot be ON at the same time
; Output result to PORTC
MOVWF temp
BTFSC temp,0 ;//Execute next line if temp,0 is HIGH
BCF temp,1
BTFSC temp,2 ;//Execute next line if temp,2 is HIGH
BCF temp,3
BTFSC temp,6 ;//Execute next line if temp,6 is HIGH
BCF temp,7
MOVF temp,0
andlw b'00001111'
movwf PORTB
movf temp,0
andlw b'11110000'
movwf PORTC
movf temp,0
return
add_green
movwf temp
btfss temp,3 ;If greenLED is LOW execute next line
bsf temp,3
movf temp,0
return
;
; -------------------------------------------
; RECEIVE CHARACTER FROM RS232 AND STORE IN W
; -------------------------------------------
; This routine does not return until a character is received.
;
receive btfss PIR1,RCIF ; (5) check for received data
goto receive
data_received
movf RCREG,W ; save received data in W
return
check_init
; waits to receive 'jbpro' from the router meaning that the software is up and running
; after the message is received, the greenLED is turned on and microcontroller can drive the car
call receive_delay
sublw 'j'
btfss STATUS, Z
goto check_init
call receive_delay
sublw 'b'
btfss STATUS, Z
goto check_init
call receive_delay
sublw 'p'
btfss STATUS, Z
goto check_init
call receive_delay
sublw 'r'
btfss STATUS, Z
goto check_init
call receive_delay
sublw 'o'
btfss STATUS, Z
goto check_init
#if DEBUG
;prints message and goes in to an endless loop of flashing greenLED
call message
Loop
; movlw greenLED
movlw 0xff
movwf PORTB ;set all bits on
call Delay ;this waits for a while!
movlw 0x00
movwf PORTB
call Delay
goto Loop ;go back and do it again
#endif
return
receive_delay
;299993 cycles
movlw 0x5E
movwf d1
movlw 0xEB
movwf d2
delay_0
btfsc PIR1,RCIF ;check for serial data
goto got_data ;if we do, goto got_data!
decfsz d1, f
goto $+2
decfsz d2, f
goto delay_0
movlw 0x00
return
got_data ;move data in to W
btfsc PIR1,RCIF
movf RCREG,W
return
#if DEBUG
Delay movlw d'250' ;delay 250 ms (4 MHz clock)
movwf temp
d11 movlw 0xC7
movwf d1
movlw 0x01
movwf d2
Delay_0
decfsz d1, f
goto $+2
decfsz d2, f
goto Delay_0
decfsz temp ,f
goto d11
retlw 0x00
#endif
;
; -------------------------------------------------------------
; SEND CHARACTER IN W VIA RS232 AND WAIT UNTIL FINISHED SENDING
; -------------------------------------------------------------
;
send
#if DEBUG
movwf TXREG ; send data in W
TransWt bsf STATUS,RP0 ; RAM PAGE 1
WtHere btfss TXSTA,TRMT ; (1) transmission is complete if hi
goto WtHere
bcf STATUS,RP0 ; RAM PAGE 0
#endif
return
;
; -------
; MESSAGE
; -------
;
message
#if DEBUG
movlw '1'
call send
movlw '6'
call send
movlw 'F'
call send
movlw '6'
call send
movlw '2'
call send
movlw '8'
call send
movlw ' '
call send
movlw 'a'
call send
movlw 'l'
call send
movlw 'i'
call send
movlw 'v'
call send
movlw 'e'
call send
movlw 0x0D ; CR
call send
movlw 0x0A ; LF
call send
#endif
return
ENDSee my next post for the rest of the question, it was to long to post at once
Last edited:
