;********************************************************************** ; Something to do with a PIC * ;********************************************************************** ; * ; Filename: snipp.asm * ; Date: 2000-09-19 * ; File Version: 0.1B * ; * ; Author: Tony Kübek * ; Company: Flintab AB * ; * ; * ;********************************************************************** ; * ; Files required: * ; * ; * ; * ;********************************************************************** ; * ; Notes: * ; * ;********************************************************************** 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 ; 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 ; caulculates timer1 delay when prescale is 1:8, adjust for rounding errors #define CALC_TIMER(TickTime) (0xFFFF-((TickTime*XTAL_FREQ)/32000))+1 ; used for I2C calculations #define I2CClock D'100000' ; define I2C bite rate #define I2C_ClockValue (((XTAL_FREQ/I2CClock)/4) -1) ; ;***** RAM VARIABLES DEFINITIONS ; *** Bank0 *** 80 bytes CBLOCK 0x020 Main_Temp:3 ; temporary variables in main loop ( 3 byte ! ) Temp:1 ; temp byte ONLY to be used locally and no calls ! EE_Byte:1 ; for reading/writing to eeram 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 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 ; ****************** 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 eventuntual table boundary crossing ; set's up the PCLATH register correctly ; Offset must be in w-reg, offset 0 jumps to the next instr. ; 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 ;+++++ ; SET_PCLATH 'help' macro for LONG_CALL ; Set's/clears PCLATH bits 3:4 according to ; 'variable' PCLATH_34 ; SET_PCLATH MACRO PCLATH_34 IF(PCLATH_34&0x10) BSF PCLATH,4 ELSE BCF PCLATH,4 ENDIF IF(PCLATH_34&0x08) BSF PCLATH,3 ELSE BCF PCLATH,3 ENDIF ENDM ;+++++ ; SET_PCLATH4 'help' macro for LONG/SHORT_CALL ; Set's/clears PCLATH bit 4 according to ; 'variable' PCLATH_4 ; SET_PCLATH4 MACRO PCLATH_4 IF(PCLATH_4&0x10) BSF PCLATH,4 ELSE BCF PCLATH,4 ENDIF ENDM ;+++++ ; SET_PCLATH3 'help' macro for LONG/SHORT_CALL ; Set's/clears PCLATH bit 3 according to ; 'variable' PCLATH_3 ; SET_PCLATH3 MACRO PCLATH_3 IF(PCLATH_3&0x08) BSF PCLATH,3 ELSE BCF PCLATH,3 ENDIF ENDM ;+++++ ; LONG_CALL long call, sets the page bits 4:5 of PCLATH ; so call can cross ANY page boundary, reset's PCLATH after call. ; w-reg is left untouched. LONG_CALL MACRO LABEL LOCAL DEST_HIGH, SOURCE_HIGH, DIFF_HIGH DEST_HIGH SET (HIGH(LABEL)&0x18) ; save bit's 4:5 of dest adress SOURCE_HIGH SET (HIGH($)&0x18) ; --- || --- source adress DIFF_HIGH SET DEST_HIGH ^ SOURCE_HIGH ; get difference ( XOR ) IF (DIFF_HIGH == 0) ; same page, SHOULD generate no extra code, delta 0 pages MESSG "Call on same page, replace LONG_CALL with PCALL " LABEL NOP ; redundant NOP's NOP CALL LABEL NOP NOP ELSE ; test if both bits must be set ? i.e. page0<->page3 or page2<->page3 IF (DIFF_HIGH == 0x18) ; difference in BOTH bit's, delta 2 pages ;MESSG "Setting page bit's for long page crossing call" SET_PCLATH DEST_HIGH ; set both bits in PCLATH CALL LABEL SET_PCLATH SOURCE_HIGH ; reset both bits in pclath ELSE ; if we end up here then one BSF/BCF is enough, i.e. delta 1 page ; i.e. page0<->1 or page2<->3 MESSG "Call only one page, replace LONG_CALL with SHORT_CALL " LABEL IF (DIFF_HIGH == 0x10) ; diff in high bit NOP ; redundant NOP SET_PCLATH4 DEST_HIGH ; set high(4) bit of PCLATH CALL LABEL SET_PCLATH4 SOURCE_HIGH NOP ; redundant NOP ELSE ; lowest bit only NOP ; redundant NOP SET_PCLATH3 DEST_HIGH ; set low(3) bit of PCLATH CALL LABEL SET_PCLATH3 SOURCE_HIGH NOP ENDIF ENDIF ENDIF ENDM ;+++++ ; SHORT_CALL short call, code for calling between page0<->1 or page2<->3 ; Reset's PCLATH after call. ; w-reg is left untouched. SHORT_CALL MACRO LABEL LOCAL DEST_HIGH, SOURCE_HIGH, DIFF_HIGH DEST_HIGH SET (HIGH(LABEL)&0x18) ; save bit's 4:5 of dest adress SOURCE_HIGH SET (HIGH($)&0x18) ; --- || --- source adress DIFF_HIGH SET DEST_HIGH ^ SOURCE_HIGH ; get difference ( XOR ) IF (DIFF_HIGH == 0) ; same page, SHOULD generate no extra code, delta 0 pages MESSG "Call on same page, replace SHORT_CALL with PCALL " LABEL NOP ; redundant NOP's CALL LABEL NOP ELSE ; for safety check so we do not require LONG_CALL IF ((DIFF_HIGH&0x18)==0x18) MESSG " WARNING ! Replace SHORT_CALL with LONG_CALL " LABEL ENDIF ;MESSG "Setting page bit's for short page crossing call" IF (DIFF_HIGH == 0x10) ; diff in high bit SET_PCLATH4 DEST_HIGH ; set high(4) bit of PCLATH CALL LABEL SET_PCLATH4 SOURCE_HIGH ELSE ; lowest bit only SET_PCLATH3 DEST_HIGH ; set low(3) bit of PCLATH CALL LABEL SET_PCLATH3 SOURCE_HIGH ENDIF ENDIF ENDM ;+++++ ; PCALL page call, code for calling on same page ; outputs messages if LONG/SHORT call could/must be used ; PCALL MACRO LABEL LOCAL DEST_HIGH, SOURCE_HIGH, DIFF_HIGH DEST_HIGH SET (HIGH(LABEL)&0x18) ; save bit's 4:5 of dest adress SOURCE_HIGH SET (HIGH($)&0x18) ; --- || --- source adress DIFF_HIGH SET DEST_HIGH ^ SOURCE_HIGH ; get difference ( XOR ) IF (DIFF_HIGH == 0) ; same page, call ok CALL LABEL ELSE ; for safety check so we do not require LONG_CALL IF ((DIFF_HIGH&0x18)==0x18) MESSG " WARNING ! Replace PCALL with LONG_CALL " LABEL CALL LABEL ; INCORRECT Call !!! ELSE MESSG " WARNING ! Replace PCALL with SHORT_CALL " LABEL CALL LABEL ENDIF ENDIF 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 ;+++++ ; 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_IRQ BTFSS INTCON,INTF ; test if external irq GOTO INT_TEST_RX_IRQ ; nope check next ; ad irq PCALL IRQ_INT_HANDLER ; dummy BCF INTCON,INTF ; clear int pin flag INT_TEST_RX_IRQ BTFSS PIR1,RCIF ; test if serial recive irq GOTO INT_TEST_TX_IRQ ; nope check next ; rx irq PCALL RX_INT_HANDLER ; dummy BCF PIR1,RCIF ; clear rx int flag INT_TEST_TX_IRQ BTFSS PIR1,TXIF ; test if serial transmit irq GOTO INT_TEST_TIMER1 ; tx irq PCALL TX_INT_HANDLER ; dummy BCF PIR1,TXIF ; clear tx int flag INT_TEST_TIMER1 BANKSEL PIE1 ; select SFR bank BTFSS PIE1,TMR1IE ; test if interrupt is enabled GOTO INT_EXIT ; no, so exit ISR BCF STATUS,RP0 ; select SFR bank BTFSS PIR1,TMR1IF ; test if Timer1 rollover occured GOTO INT_EXIT ; no so exit isr BCF PIR1,TMR1IF ; clear Timer1 H/W flag BANKSEL T1CON ; select SFR bank MOVLW LOW(CALC_TIMER(D'100')) MOVWF TMR1L ; initialize Timer1 low MOVLW HIGH(CALC_TIMER(D'100')) ; MOVWF TMR1H ; initialize Timer1 high BSF T1CON,TMR1ON ; turn ON Timer1 module INT_EXIT PULL ; restore registers RETFIE ; return from interrupt ;*************** end int routine ************************************* ; *********************************************************************** ; ; RX_INT_HANDLER - handles the received commands on serial com ; called from inside int. ; RX_INT_HANDLER RETURN ; *********************************************************************** ; ; TX_INT_HANDLER - handles the tramission of bytes on serial com ; called from inside int. ; TX_INT_HANDLER RETURN ; *********************************************************************** ; EE_WRITE_BYTE - Routine to write a byte to ee ram ; Adress in W, byte MUST be in EE_Byte EE_WRITE_BYTE BANK2 ; select bank2 MOVWF EEADR ; setup adress BANK0 ; MOVF EE_Byte,W ; get byte BANK2 MOVWF EEDATA ; setup byte to write BSF STATUS,RP0 ; bank3 !! BCF EECON1,EEPGD ; set to data ee ram BSF EECON1,WREN ; enable writes DISABLE_IRQ ; disable irq's MOVLW H'55' ; required sequence !! MOVWF EECON2 MOVLW H'AA' MOVWF EECON2 BSF EECON1,WR ; begin write procedure ENABLE_IRQ ; enable irq's again BCF EECON1,WREN ; disable writes ( does not affect current write cycle ) BANK0 ; reset to bank0 ; wait for the write to complete before we return BTFSS PIR2,EEIF ; wait for interrupt flag to be set GOTO $-1 ; clear interupt bit and write enable bit BCF PIR2,EEIF ;clear eewrite irq flag RETURN ; *********************************************************************** ; EE_READ_BYTE - Routine to read a byte from ee ram ; Adress in W, byte will be delivered in W EE_READ_BYTE BANK2 MOVWF EEADR ; put in adress reg. BSF STATUS,RP0 ; bank3 !! BCF EECON1,EEPGD ; set to read data memory BSF EECON1,RD ; set bit to read BCF STATUS,RP0 ; bank2 !! MOVF EEDATA,W ; move data to W BANK0 ; Reset to BANK0 ! RETURN ; and return ; *********************************************************************** ; IS_HEX - Routine to check if value in W is ASCII hex digit 0-9, A-F or a-f ; Returns with zero SET if NOT hex ( value preserved ) ; Else returns with zero flag clear and value of input as binary in W ; IS_HEX ; 0-9 A-F a-f Z ; 0x30-0x39 0x41-0x46 0x61-0x66 0x4A ADDLW 0xC6 ; 0xF6-0xFF 0x07-0x0C 0x27-0x2C 0x10 ADDLW 0x0A ; 0x00-0x09 0x11-0x16 0x31-0x36 0x1A BTFSC STATUS,C GOTO IS_09 ADDLW 0xE9 ; 0xFA-0xFF 0x1A-0x1F 0x03 ADDLW 0x06 ; 0x00-0x05 0x20-0x25 0x09 BTFSC STATUS,C GOTO IS_AF ADDLW 0xDA ; 0xFA-0xFF 0xE3 ADDLW 0x06 ; 0x00-0x05 0xE9 BTFSC STATUS,C GOTO IS_AF ADDLW 0x61 ; 0x4A BSF STATUS,Z ; SET zero flag value is not HEX and return RETURN IS_AF ADDLW 0x0A ; add ten ( range is A-F ) IS_09 BCF STATUS,Z ; clear zero flag value is HEX 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 ) SHORT_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 SHORT_CALL INIT_PORTS ; setup uart SHORT_CALL INIT_UART ; setup I2C SHORT_CALL INIT_I2C ; setup timer1 SHORT_CALL INIT_TIMER1 ; setup configurable parameters ( read from EE ram ) SHORT_CALL INIT_PARAMS ; all pins/periphials configured, enable global irq ENABLE_IRQ BANK0 MAIN_LOOP ; main loop ; test for specific events MAIN_DONE NOP NOP NOP NOP ; and return to main loop GOTO MAIN_LOOP ORG 0x0800 ; second page ORG 0x1000 ; third page ; *********************************************************************** ; ; 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 all porta 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 ; 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 is analoge input from keyboard, bit 1 is key available ; 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' ; RB0 input ( int ) ( se also option ) the rest outputs 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'11011100';b'11010100'; 7-6 for uart must be set,4 (SDI) MUST be input i.e set ; 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_TIMER1 - Initialises Timer1 module ; ; Make sure to be at bank0 INIT_TIMER1 MOVLW T1CON ; get adress for timer1 control reg MOVWF FSR ; setup fsr MOVLW b'00110000' ; 1:8 prescale, 100mS rollover MOVWF INDF ; initialize Timer1 MOVLW LOW(CALC_TIMER(D'100')) MOVWF TMR1L ; initialize Timer1 low MOVLW HIGH(CALC_TIMER(D'100')) ; MOVWF TMR1H ; initialize Timer1 high BCF PIR1,TMR1IF ; ensure flag is reset BSF T1CON,TMR1ON ; turn on Timer1 module ; enable TIMER1 interrupt MOVLW PIE1 ; get adress for periphial irq's MOVWF FSR ; setup fsr BSF INDF,TMR1IE ; enable TIMER1 irq BSF INTCON,PEIE ; and periphial irq must also be enabled RETURN ; return from subroutine ; *********************************************************************** ; ; 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) ;BAUD_9600 ; get baudrate 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 high 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_I2C - Initialises I2C, module, 100Khz, master mode, ; Make sure to be at bank0 INIT_I2C ; make sure pins are setup before calling this routine ; setup MSSP adress register MOVLW SSPADD ; get adress for synch serial port status reg MOVWF FSR ; setup fsr MOVLW I2C_ClockValue ; setup clock rate MOVWF INDF ; and store it ; setup MSSP status reg MOVLW SSPSTAT ; get adress for synch serial port status reg MOVWF FSR ; setup fsr MOVLW (1<<SMP) ; enable slewrate control MOVWF INDF ; and store it ; setup MSSP control reg MOVLW SSPCON ; get adress for synch serial port control reg MOVWF FSR ; setup fsr MOVLW ((1<<SSPEN)|(1<<CKP)|(1<<SSPM3)); enable syncronous port, enable clock , ; I2C master mode clock = OSC/(4*(SSPADD)+1) MOVWF INDF ; and set it ; enable MSSP interrupt MOVLW PIE1 ; get adress for periphial irq's MOVWF FSR ; setup fsr BSF INDF,SSPIE ; enable MSSP irq BSF INTCON,PEIE ; and periphial irq must also be enabled (if not already ) RETURN ; *********************************************************************** ; ; INIT_PARAMS - Initialises user ram with parameters stored in EE ram ; I.e. load values from ee ram offset 0 to ram area offset Ad_ModeReg ; parameters must be in contignous ram area. ; Make sure to be at bank0 ; INIT_PARAMS MOVLW EERAM_End ; number of bytes MOVWF Temp ; store temporarily MOVLW StartRam ; get base adress ( of first byte in contignous ram ) MOVWF FSR ; setup FSR CLRF EE_Byte ; start adress in EE ram INIT_PARAMS_LOOP MOVF EE_Byte,W ; store adress SHORT_CALL EE_READ_BYTE ; get byte MOVWF INDF ; put it in ram INCF FSR,F ; increase dest. adress INCF EE_Byte,F ; increase source adress DECF Temp,F ; decrement byte counter BTFSS STATUS,Z GOTO INIT_PARAMS_LOOP ; continue RETURN ; all ram filled ORG 0x2100 ; 256 bytes of eeram EERAM_Base EQU $ ADModeEE EQU $-EERAM_Base ; two bytes of ad mode DW 0x31 DW 0x80 ; cont. conv. 24 bit, 0-10mV, unipolar, 5 V ref, ; channel Ain1+ Ain1- EERAM_End EQU $-EERAM_Base END ; directive 'end of program'
Questions:
I've successfully implemented an ADC and a USART project in f877. However, I can't make the two work as one project. Can anyone provide me the correct order for initialization? Any comments will be valued. Thanks.
Hi,
I'm in the process of designing a humidity data logger. The sensor i'm using is the sensirion SHT11 (datasheets are found on http://www.sensirion.com ) I am having some problems with I2C initialisation.. Could you please help me? Could you please suggest how best to connect sensor and a simple code to read data...
Thanks,Regards,
Steve
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Comments:
To safely initialize the PIC (any processor, really) and get the interrupts to be stable on powerup, do the following in this order: A) Set up all of the TRIS and ADCON registers. B) Initialize all the static port outputs. C) Set up all memory variables and pointers. D) initialize all the interrupts in any order you like except the GIE bit. E) Set the GIE bit. F) Jump to the running code loop.+
When generating code and using multiple prefab code sets, merge the approriate sections: Defines and memory locations, ISR code (you only have 1 interrupt vector for the 16F8xx series, for instance - use polling inside the master ISR routine for each interrupt bit) Hint: Don't simply excape the ISR is one of the bits is not set. Check each bit and branch to the next bit test if not set. Call the appropriate interrupt code after each test.
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