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
file: /Techref/microchip/16f876-hint-tk.htm, 27KB, , updated: 2018/9/28 15:21, local time: 2024/11/3 23:41,
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