by Tony Kübek
; UART test with TX and RX buffers By Tony Kübek 2000-06-22 free for use
; NOTE Buffer macro is for NON_COMMERCIAL use, originator Eric Smith
; Tried to contact him but failed to do so so this remark remains.
; Other than that no warranties are implied or anything like that
; use it at your own risk ;-)
;
list p=16f876 ; list directive to define processor
#include <p16f876.inc> ; processor specific variable definitions
#include <macros.asm> ; macro definitions
__CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_ON & _HS_OSC & _WRT_ENABLE_ON & _LVP_OFF& _DEBUG_ON & _CPD_OFF
; '__CONFIG' directive is used to embed configuration data within .asm file.
; The lables following the directive are located in the respective .inc file.
; See respective data sheet for additional information on configuration word.
; turn off crossing page boundary message
ERRORLEVEL -306, -302
; base frequency
XTAL_FREQ EQU 20000000 ; OSC freq in Hz
; handy ASCII character table
STX EQU 0x02 ; stx
ETX EQU 0x03 ; etx
BEL EQU 0x07 ; bell
BS EQU 0x08 ; backspace
TAB EQU 0x09 ; horizontal tab
LF EQU 0x0A ; line feed
FF EQU 0x0C ; form feed
CR EQU 0x0D ; carriage return
XON EQU 0x11 ; transmit on
XOFF EQU 0x13 ; transmit off
EOF EQU 0x1A ; end of file
ESC EQU 0x1B ; escape
SP EQU 0x20 ; space
; buffers for serial communication
RX_BUFFER_SIZE EQU 16 ; serial receive buffer allocation ( best when power of 2 )
TX_BUFFER_SIZE EQU 16 ; serial transmit buffer allocation
; Baud rate constants from (((10*XTAL_FREQ/(16*BAUD))+5)/10)-1
; note these calulations uses BRGH = 1 ( high speed mode )
; for BRGH = 0 use the formula: (((10*XTAL_FREQ/(64*BAUD))+5)/10)-1
; NOTE Rather use the calculations further down below instead !
BAUD_9600 EQU (((10*XTAL_FREQ/(16*9600))+5)/10)-1
BAUD_19200 EQU (((10*XTAL_FREQ/(16*19200))+5)/10)-1
BAUD_38400 EQU (((10*XTAL_FREQ/(16*38400))+5)/10)-1
BAUD_57600 EQU (((10*XTAL_FREQ/(16*57600))+5)/10)-1
BAUD_115200 EQU (((10*XTAL_FREQ/(16*115200))+5)/10)-1
; caulculates baudrate when BRGH = 1, adjust for rounding errors
#define CALC_HIGH_BAUD(BaudRate) (((10*XTAL_FREQ/(16*BaudRate))+5)/10)-1
; caulculates baudrate when BRGH = 0, adjust for rounding errors
#define CALC_LOW_BAUD(BaudRate) (((10*XTAL_FREQ/(64*BaudRate))+5)/10)-1
;***** RAM VARIABLES DEFINITIONS
; *** Bank0 *** 80 bytes
CBLOCK 0x020
Temp:1 ; temp byte ONLY to be used locally and no calls !
SendStrIndex:1 ; Used as an index into the string table ( temporary )
SendStrTmp:1 ; Save a copy of which string we're to write ( temporary )
; serial buffer RX and TX pointers, buffers located in bank1
RX_Buffer_InPtr:1 ; where to put next incomming byte
RX_Buffer_OutPtr:1 ; where to get next ( first ) byte
RX_Buffer_Count:1 ; how many we have in buffer
TX_Buffer_InPtr:1 ; where to put next outgoing byte
TX_Buffer_OutPtr:1 ; whre to get next byte
TX_Buffer_Count:1 ; how many we have in buffer
TX_Temp:1 ; temporary reg used while sending
COM_Flags:1 ; flags for serial comunincation
ENDC
; *** Bank0/1/2/3 mirrored in all banks 0x70, 0xF0, 0x170, 0x1F0, 16 bytes
CBLOCK 0x070
ICD_Reserved1:1 ; for icd
; ram variables accesible from all banks mainly used for context saving
; ( ram area above 0x70 are mirrored in all banks )
Saved_W:1 ; variable used for context saving
Saved_Status:1 ; variable used for context saving
Saved_Pclath:1 ;
Saved_Fsr:1 ;
Table_Temp:1 ; table lookup temp variable
ENDC
; *** Bank1 *** 80 bytes
CBLOCK 0x0A0
RX_Buffer:RX_BUFFER_SIZE ; buffer for receving
TX_Buffer:TX_BUFFER_SIZE ; buffer for sending
ENDC
; *** Bank2 *** extra ram 16 bytes
CBLOCK 0x110
ENDC
; *** Bank2 *** 80 Bytes
CBLOCK 0x120
ENDC
; *** Bank3 *** extra ram 16 bytes
CBLOCK 0x190
ENDC
; *** Bank3 *** 80 bytes
CBLOCK 0x1A0
ENDC
CBLOCK 0x1EB
ICD_Reserved2:5 ; for icd
ENDC
; ************* Bit variable definitions ***************************
#define _BufferOverrun COM_Flags,0 ; buffer overrun
; ****************** * Predefined strings to send by uart *****
#define STR_HELLO 0x00 ; hello world :-)
#define STR_UNKNOWN_CMD 0x01 ; unknown command
; ****************** Macro definitions ********************************
;+++++
; PAGE/BANK0/1/2/3 selects register bank 0/1/2/3.
; Leave set to BANK0 normally.
BANK0 MACRO
BCF STATUS,RP0 ; clear bank select bits
BCF STATUS,RP1
BCF STATUS,IRP ; clear indirect adressing bit
ENDM
BANK1 MACRO
BSF STATUS,RP0 ;
BCF STATUS,RP1 ;
BCF STATUS,IRP ; clear indirect adressing bit
ENDM
BANK2 MACRO
BCF STATUS,RP0 ;
BSF STATUS,RP1
BSF STATUS,IRP ; set bit for indirect adressing
ENDM
BANK3 MACRO
BSF STATUS,RP0 ;
BSF STATUS,RP1
BSF STATUS,IRP ; set bit for indirect adressing
ENDM
; macros for accessing page's directly
PAGE0 MACRO
BCF PCLATH,3
BCF PCLATH,4
ENDM
PAGE1 MACRO
BSF PCLATH,3
BCF PCLATH,4
ENDM
PAGE2 MACRO
BCF PCLATH,3
BSF PCLATH,4
ENDM
PAGE3 MACRO
BSF PCLATH,3
BSF PCLATH,4
ENDM
;+++++
; TABLE_JUMP Calculates an eventual page boundary crossing
; set's up the PCLATH register correctly
; Offset must be in w-reg, offset 0 jumps to the next instr.
; Uses one byte of dedicated ram
TABLE_JUMP MACRO
MOVWF Table_Temp ; save wanted offset
MOVLW LOW($+8) ; get low adress ( of first instr. after macro )
ADDWF Table_Temp,F ; add offset
MOVLW HIGH($+6) ; get highest 5 bits ( of first instr. after macro )
BTFSC STATUS,C ; page crossed ? ( 256 byte )
ADDLW 0x01 ; Yes add one to high adress
MOVWF PCLATH ; load high adress in latch
MOVF Table_Temp,W ; get computed adress
MOVWF PCL ; And jump
ENDM
;+++++
; PUSH/PULL save and restore W,PCLATH,STATUS and FSR registers -
; used on interrupt entry/exit
PUSH MACRO
MOVWF Saved_W ; save w reg
SWAPF STATUS,W ;The swapf instruction, unlike the movf, affects NO status bits, which is why it is used here.
CLRF STATUS ; sets to BANK0
MOVWF Saved_Status ; save status reg
MOVF PCLATH,W
MOVWF Saved_Pclath ; save pclath
CLRF PCLATH
MOVF FSR,W
MOVWF Saved_Fsr ; save fsr reg
ENDM
PULL MACRO
MOVF Saved_Fsr,W ; get saved fsr reg
MOVWF FSR ; restore
MOVF Saved_Pclath,W ; get saved pclath
MOVWF PCLATH ; restore
SWAPF Saved_Status,W ; get saved status in w
MOVWF STATUS ; restore status ( and bank )
SWAPF Saved_W,F ; reload into self to set status bits
SWAPF Saved_W,W ; and restore
ENDM
;+++++
; INC_BUFFER advance buffer pointers wrap if necessary
;
; If buffer size is power of two, and buffer is aligned
; on an multiple of twice it size, this macro generates
; two instructions, Otherwise it generates six instructions.
; Originator: Eric Smith, eric@brouhaha.com for non-comercial use.
INC_BUFFER MACRO Pointer, Base, Size
LOCAL POWER_OF2, ALIGNED,BIT,VALUE
POWER_OF2 SET !(Size&(Size-1)) ; calculate if power of 2
ALIGNED SET POWER_OF2&&((Base&(Size-1))==0) ; calculate if aligned
IF ALIGNED
VALUE SET Size
BIT SET 0
WHILE VALUE>1
BIT SET BIT+1
VALUE SET VALUE>>1
ENDW
ENDIF
INCF Pointer,F ; increase pointer
IF ALIGNED&&!(Base&(1<<BIT)) ; aligned ?
BCF Pointer,BIT ; yep clear bit
ELSE
MOVF Pointer,W ; nope
XORLW Base+Size
MOVLW Base
BTFSC STATUS,Z
MOVWF Pointer
ENDIF
ENDM
;+++++
; DISABLE_IRQ disable global irq
DISABLE_IRQ MACRO
LOCAL STOP_INT
STOP_INT BCF INTCON,GIE ; disable global interrupt
BTFSC INTCON,GIE ; check if disabled
GOTO STOP_INT ; nope, try again
ENDM
;+++++
; ENABLE_IRQ enable global irq
ENABLE_IRQ MACRO
BSF INTCON,GIE ; enable global interrupt
ENDM
; ******************* END macro definitions ***************************
;**********************************************************************
ORG 0x000 ; processor reset vector
NOP ; required for the ICD
CLRF STATUS ; ensure we are at bank0
CLRF PCLATH ; ensure page bits are cleared ( before GOTO xxx !!! )
GOTO INIT ; go to initialisation of program
;**************** Interrupt service routine **************************
ORG 0x004 ; interrupt vector location
PUSH ; save registers
INT
; Interrupt code
INT_TEST_RX_IRQ
BTFSS PIR1,RCIF ; test if serial recive irq
GOTO INT_TEST_TX_IRQ ; nope check next
; rx irq
CALL RX_INT_HANDLER ; goto rx handler
BCF PIR1,RCIF ; clear rx int flag
INT_TEST_TX_IRQ
BTFSS PIR1,TXIF ; test if serial transmit irq
GOTO INT_TEST_NXT
; tx irq
CALL TX_INT_HANDLER ; goto tx handler
BCF PIR1,TXIF ; clear tx int flag
INT_TEST_NXT
; test whatever left :-)
INT_EXIT
PULL ; restore registers
RETFIE ; return from interrupt
; ***********************************************************************
;
; RX_INT_HANDLER - handles the received commands on serial com
; called from inside int.
;
RX_INT_HANDLER
BTFSS RCSTA,OERR ; test for overrun error
GOTO RX_CHECK_FRAMING
; when overrun, uart will stop receving the continous
; recevive bit must then be reset
BCF RCSTA,CREN ; clear continous receve bit
BSF RCSTA,CREN ; and set it again
RX_CHECK_FRAMING
BTFSS RCSTA,FERR ; check from framing errors
GOTO RX_CHECK_BUFFER
; framing error do not store this byte
; read rx reg and discard byte
GOTO RX_DISCARD_BYTE
RX_CHECK_BUFFER
MOVF RX_Buffer_Count,W ; test if empty
XORLW RX_BUFFER_SIZE
BTFSC STATUS,Z
GOTO RX_BUFFER_FULL
MOVF RX_Buffer_InPtr,W ; get adress for indirect dressing
MOVWF FSR ; setup fsr
MOVF RCREG,W ; get received byte
MOVWF INDF ; and store it in buffer
INCF RX_Buffer_Count,F ; inc buffer counter
; update pointers
INC_BUFFER RX_Buffer_InPtr,RX_Buffer,RX_BUFFER_SIZE
RETURN
RX_BUFFER_FULL
; no rom for more bytes, set overrun flag
BSF _BufferOverrun
; and clear the last byte ( no room to store it ! )
RX_DISCARD_BYTE
; optional an error flag could be set to indicate comm error.
MOVF RCREG,W ; read byte and discard
RETURN
; ***********************************************************************
;
; TX_INT_HANDLER - handles the tramission of bytes on serial com
; called from inside int.
;
TX_INT_HANDLER
MOVF TX_Buffer_Count,W ; get number of bytes
BTFSC STATUS,Z ; buffer empty ?
GOTO TX_BUFFER_EMPTY
MOVF TX_Buffer_OutPtr,W ; get adress for indirect adressing
MOVWF FSR ; setup fsr
MOVF INDF,W ; get byte
MOVWF TXREG ; and put it in tx reg
DECF TX_Buffer_Count,F ; decrement buffer counter
; update pointers
INC_BUFFER TX_Buffer_OutPtr,TX_Buffer,TX_BUFFER_SIZE
RETURN
TX_BUFFER_EMPTY
; no more bytes to send disable TX irq
; code is to avoid bank switching ( using FSR )
MOVLW PIE1 ; get adress for tx irq enable
MOVWF FSR ; setup fsr
BCF INDF,TXIE ; and disable tx irq
RETURN
; ***********************************************************************
;
; TX_ADD_BUFFER - Puts one byte in serial tx buffer, blocks until room available
; Make sure to be at bank0 ( buffer pointers in bank0, buffers in bank1 )
;
TX_ADD_BUFFER
MOVWF TX_Temp ; store byte temporarily
TX_ADD_TST
MOVF TX_Buffer_Count,W ; get count
XORLW TX_BUFFER_SIZE
BTFSC STATUS,Z ; test if any room
GOTO TX_ADD_TST ; nope no room, wait until there is
MOVF TX_Buffer_InPtr,W ; get adress to store byte
MOVWF FSR ; setup fsr
MOVF TX_Temp,W ; get byte
MOVWF INDF ; and store it
; update buffer pointers
INC_BUFFER TX_Buffer_InPtr,TX_Buffer,TX_BUFFER_SIZE
INCF TX_Buffer_Count,F ; increment byte count
; MUST not be done until after byte is stored in buffer
; and pointers updated
MOVLW PIE1 ; get adress for periphial irq
MOVWF FSR ; setup fsr
BSF INDF,TXIE; and enable tx irq
RETURN
; ***********************************************************************
;
; RX_GET_BUFFER - Gets one byte from in serial rx buffer, if available
; If no bytes in buffer zero flag is set else zero flag is cleared
; Make sure to be at bank0 ( buffer pointers in bank0, buffers in bank1 )
;
RX_GET_BUFFER
MOVF RX_Buffer_Count,F ; check if anything available ?
BTFSC STATUS,Z ;
RETURN ; nope, nothing there, NOTE zero flag set !
; get pointer
MOVF RX_Buffer_OutPtr,W
MOVWF FSR ; setup FSR
; update buffer pointers
INC_BUFFER RX_Buffer_OutPtr,RX_Buffer,RX_BUFFER_SIZE
; get byte to W
MOVF INDF,W
; decrement counter
DECF RX_Buffer_Count,F
BCF STATUS,Z ; make sure zero flag is clear
RETURN
; ***********************************************************************
; INIT - Cold start vector, called at startup
;
; initilaize all ports to known state before setup routines are called
;
INIT
; pclath and status is already cleared !
; before entering this init routine
CLRF INTCON ; ensure int reg is clear
CLRF PIR1 ; clear periphial irq's
CLRF PIR2 ; ditto
; make sure all individual irq's are disabled
MOVLW PIE1 ; get adress for periphial irq enable
MOVWF FSR ; setup fsr
CLRF INDF ; and clear irq enable flags
MOVLW PIE2 ; get adress for second periphial irq enable
MOVWF FSR ; setup fsr
CLRF INDF ; and clear irq enable flags
; note porta as is set as ANALOGUE i/o as default
; clear output data latches
CLRF PORTA
CLRF PORTB
CLRF PORTC
; call initialize routines for periphials/ports
; note must be at bank0 during initializing
; NOTE ! DO NOT CHANGE ORDER OF THESE ROUTINES !!
; clear all user ram ( set to all 0's )
CALL CLEAR_RAM
; setup our ports to in/out/analogue/rx/tx/spi/etc
; must be done before calling any other INIT_XXX routine
; as most of them depends on pin settings
CALL INIT_PORTS
; setup uart
CALL INIT_UART
; initialize buffers/pointers
CALL INIT_BUFFERS
; all pins/periphials configured, enable global irq
ENABLE_IRQ
;a welcome message
MOVLW STR_HELLO
CALL SEND_STRING
MAIN_LOOP
; main loop
NOP ; do whatever should be done every loop
; test for specific events
MAIN_COM_EVENT
; test if a character is received ( i.e. saved in rx buffer )
CALL RX_GET_BUFFER
; test zero flag
BTFSC STATUS,Z
GOTO MAIN_DONE ; nope zero flag set=no byte recieved, test next event
; *****************************
; a byte is recevied !
; *****************************
; do whatever needs to be done
; *****************************
; Something that's neat to put here is the code
; generated by Nicolai's autogenerated parser ( top stuff )
; from the picfaq site:
; http://www.piclist.com/techref/default.asp?url=piclist/codegen
; *****************************
NOP
NOP
MAIN_DONE
NOP
NOP
NOP
NOP
; and return to main loop
GOTO MAIN_LOOP
; ***********************************************************************
;
; CLEAR_RAM - Reset all general purpose ram to 0's
; Note ! does not clear watchdog, add CLRWDT where appropiate if enabled
; Make sure to be at bank0
;
CLEAR_RAM
MOVLW 0x20 ; start ram bank0
MOVWF FSR
CLEAR_BANK0
CLRF INDF ; Clear a register pointed to be FSR
INCF FSR,F
MOVLW 0x7F ; Test if at top of memory bank0
SUBWF FSR,W
BNZ CLEAR_BANK0 ; Loop until all cleared
MOVLW 0xA0 ; start ram bank1
MOVWF FSR
CLEAR_BANK1
CLRF INDF ; Clear a register pointed to be FSR
INCF FSR,F
; note this could also be set to 0xFF or 0xEF as the top 16 bytes are mirrored from
; bank0
MOVLW 0xEF ; Test if at top of memory bank1
SUBWF FSR,W
BNZ CLEAR_BANK1 ; Loop until all cleared
BANK2 ; select bank2/3 ( with indirect adressing )
MOVLW 0x10 ; start ram bank2
MOVWF FSR
CLEAR_BANK2
CLRF INDF ; Clear a register pointed to be FSR
INCF FSR,F
; note this could also be set to 0x7F or 0x70 as the top 16 bytes are mirrored from
; bank0
MOVLW 0x70 ; Test if at top of memory bank2
SUBWF FSR,W
BNZ CLEAR_BANK2 ; Loop until all cleared
MOVLW 0x90 ; start ram bank3
MOVWF FSR
CLEAR_BANK3
CLRF INDF ; Clear a register pointed to be FSR
INCF FSR,F
; note this could also be set to 0xFF or 0xEF as the top 16 bytes are mirrored from
; bank0
MOVLW 0xEF ; Test if at top of memory bank3
SUBWF FSR,W
BNZ CLEAR_BANK3 ; Loop until all cleared
BANK0 ; set back to bank0
RETURN
; ***********************************************************************
;
; INIT_PORTS - Initialises all ports on the PIC
; i.e sets the pins as in/out/analog/etc
; Make sure to be at bank0
INIT_PORTS
; setup PORTA
; set RA0 analogue and the rest of the pins digital
MOVLW ADCON1 ; get adress for ad/module config1 reg
MOVWF FSR ; setup fsr
MOVLW (1<<PCFG3)|(1<<PCFG2)|(1<<PCFG1); RA0 analoge the rest digital !!
; result LEFT justified
MOVWF INDF ; and store it
; enable/shutoff ad/module
MOVLW ADCON0 ; get adress for ad/module config reg
MOVWF FSR ; setup fsr
MOVLW (1<<ADCS1)|(1<<ADON) ; enable ad-module, ad clock is osc/32
MOVWF INDF ; and set it
; set in/out for porta pins
MOVLW TRISA ; get adress for porta control reg
MOVWF FSR ; setup fsr
MOVLW b'00000011' ; bit 0 and bit 1 is inputs
; the rest is outputs
MOVWF INDF ; and set it
; setup PORTB
; set in/out for portb pins
MOVLW TRISB ; get adress for portb control reg
MOVWF FSR ; setup fsr
MOVLW b'00000001' ; all outputs except RB0 ( int ) ( se also option )
MOVWF INDF ; and set it
; setup PORTC
; note PORTC must be setup properly when using SPI/UART/CCP/TIMER
; look in data sheet, some setups are 'unlogical' and/or overridden
; as TX pin configured as input etc.
; set in/out for portc pins
MOVLW TRISC ; get adress for portc control reg
MOVWF FSR ; setup fsr
MOVLW b'11010000'; 7-6 for uart must be set,4 (SDI) MUST be input i.e set ( for SPI master )
; 5 ( SDO ) must be cleared, 3 (SCK) must be cleared
; for master mode. 1-2 is for CCP module, 0 is for timer inp.
MOVWF INDF ; and set it
; setup OPTION reg
MOVLW OPTION_REG; get adress for option reg
MOVWF FSR ; setup fsr
MOVLW b'00000000' ; pull up portb by latch, int edge falling,TMR0 source internal
; TMR0 source edge inc on low->high, prescaler to Timer0, TMR0 rate 1:2
MOVWF INDF ; and set it
RETURN
; ***********************************************************************
;
; INIT_UART - Initialises UART
; enables recevier and transmitter
; Make sure to be at bank0
INIT_UART
; make sure pins are setup before calling this routine
; TRISC:6 and TRISC:7 must be set ( as for output, but operates as input/output )
; furthermore its advised that interrupts are disabled during this routine
; setup baudrate
MOVLW SPBRG ; get adress for serial baud reg
MOVWF FSR ; setup fsr
MOVLW CALC_LOW_BAUD(19200) ; calculate baudrate is this example 19200 with brgh=0
MOVWF INDF ; and store it
; enable transmitter
MOVLW TXSTA ; get adress for serial enable reg
MOVWF FSR ; setup fsr
MOVLW (1<<TXEN) ;|(1<<BRGH); preset enable transmitter and low speed mode
MOVWF INDF ; and set it
; enable recevier
MOVLW (1<<SPEN)|(1<<CREN) ; preset serial port enable and continous recevie
MOVWF RCSTA ; set it
; enable reciever interrupt
MOVLW PIE1 ; get adress for periphial irq's
MOVWF FSR ; setup fsr
BSF INDF,RCIE ; enable reciever irq
BSF INTCON,PEIE ; and periphial irq must also be enabled
RETURN
; ***********************************************************************
;
; INIT_BUFFERS - Initialises all buffers and pointers
; Make sure to be at bank0
INIT_BUFFERS
; setup receive buffer
CLRF RX_Buffer_Count ; clear counter
MOVLW RX_Buffer ; get base adress for buffer
MOVWF RX_Buffer_InPtr ; save as in adress
MOVWF RX_Buffer_OutPtr; and out adress
; setup transmit buffer
CLRF TX_Buffer_Count ; clear counter
MOVLW TX_Buffer ; get base adress for buffer
MOVWF TX_Buffer_InPtr ; save as in adress
MOVWF TX_Buffer_OutPtr; and out adress
RETURN
; ***********************************************************************
; SEND_STRING - Send a string on the serial communication ( put into tx buffer )
; The purpose of this routine is to send an string on the serial communication.
; On entry, W contains the string number to be sent.
;
; Memory used
; SendStrIndex,SendStrTmp ( only locally for each call )
; Calls
; TX_ADD_BUFFER
; Inputs
; W = String Number
;
SEND_STRING
CLRF SendStrIndex ;Used as an index into the string table
MOVWF SendStrTmp ;Save a copy of which string we're to write
SEND_GET_CHAR
CLRC ; clear carry ( so it dosent affect byte rotation )
RLF SendStrTmp, W ; Get the saved copy and multiply it by two
TABLE_JUMP ; tablejump macro jumps W number of lines
; 'auto' adjust for 256 bytes boundary
CALL STRING0 ; Get next character in the string
GOTO SEND_CHAR
CALL STRING1
SEND_CHAR
ANDLW 0xFF ; "Return" point for computed goto's.
BTFSC STATUS, Z ; If the returned byte is zero, end reached
RETURN
CALL TX_ADD_BUFFER ; Send a single character
INCF SendStrIndex, F ; Point to the next character in the string
GOTO SEND_GET_CHAR ; get the next one
STRING0
MOVF SendStrIndex, W ; Get the string index
TABLE_JUMP ; tablejump macro jumps W number of lines
; adjust for 256 bytes boundary
; directive dt generates a number of RETLW lines !
; i.e. equal to RETLW 'H' RETLW 'E' ....
dt "HELLO WORLD",0x0D,0x0A,0x00 ;Note the zero termination.
STRING1
MOVF SendStrIndex, W
TABLE_JUMP
dt "UNKNOWN COMMAND !",0x0D,0x0A,0x00 ;Note the zero termination.
Questions:
halo, i am using 16f876a in my project.
i use the uart in pic(pin rx and tx).
but my project need 2 serial port.
i knew that can implement software uart in other type of pic without uart, but can the software uart implement again in pic that already have uart built in like 16f876a?
will it crach with the hardware uart?
if can, by refer to software uart for 16f84, which code should modify?
Hello,
i am using your usart routines for simplex serial comm, 16f877A to computer. hyper terminal configured at 9600,N,8,1. 16f877A send 'Z' to computer but i receive garbague insted of 'Z'.
plz pointout where is the problem i send my .asm file.
Many Thanks
M.Zubair
PROCESSOR 16f877a
#include "p16f877a.inc"
__CONFIG _HS_OSC & _WDT_OFF & _PWRTE_ON & _LVP_OFF
BAUD_9600 EQU (((10*20000000/(64*9600))+5)/10) - 1
org 0
NOP
NOP
goto START
;**************** main start ****************
START
bsf STATUS,RP0 ;bank1
bcf STATUS,RP1
movlw b'11010000' ; tx/rx as an input port
movwf TRISC
clrf TRISB ; port b is an output port
; setup baudrate
movlw BAUD_9600
movwf SPBRG
; enable transmitter
movlw b'00000100'
movwf TXSTA ; get adress for serial enable reg
; enable recevier
movlw 'Z'
movwf TXREG
bsf TXSTA,TXEN
bcf STATUS,RP0 ; BANK0
bcf STATUS,RP1
movlw b'10010000'
movwf RCSTA ; set it
TOP movlw 'Z'
movwf TXREG
bsf STATUS,RP0 ;bank1
TOP1 btfss TXSTA,TRMT
goto TOP1
bcf STATUS,RP0 ; BANK0
goto TOP
END
I am also trying to use Tony Kubek's code, but to write to a Compact Flash card using a PIC16F877. I also require the macros.asm file. Is there any chance of getting hold of it? Cheers!
I tried my code, I tried Tony Kubek's code, but I can't get the communication to work. For example, Kubek's code gives me ' |ç'. I suppose I have a problem of communication parameter, but my parameters seem good : 9600 bauds, 8 bits data, no parity, 1 stop bit. What else could go wrong?
Hallo, my name is Riccardo Melotti from italy I use a pic18f452 with its integrate serial(USART) comunication. I want to implement a comunication protocol e,7,1 (1 start bit,parity even,7 data bits and 1 stop bit) You can help me to implement the register configuration ( in asm o in embeddede c) RCSTA TXSTA ecc I have just implement the n,8,1(1 start bit,no parity, 8 data bits and 1 stop bit) without problem Any information about this is very important for me. Thank yuo very much. Good work
Comments:
I've just found that the macros.asm isn't actually needed, that line may be deleted or commented out, and the program assembles OK. A macro is used, but the code is included in the source code.
Leon