#define CANROU_SOURCE #include #include "CANDef.inc" ; CAN routines in assembly code CANROU_start CODE ;**************************************************************************** ;* Function: void CANInitializeFunc(BYTE SJW, ;* BYTE BRP, ;* BYTE PHSEG1, ;* BYTE PHSEG2, ;* BYTE PROPSEG, ;* enum CAN_CONFIG_FLAGS flags) ;* ;* Input: m_SJW - SJW value as defined in 18CXX8 datasheet ;* (Must be between 1 thru 4) ;* m_BRP - BRP value as defined in 18CXX8 datasheet ;* (Must be between 1 thru 64) ;* m_PHSEG1 - PHSEG1 value as defined in 18CXX8 datasheet ;* Must be between 1 thru 8) ;* m_PHSEG2 - PHSEG2 value as defined in 18CXX8 datasheet ;* (Must be between 1 thru 8) ;* m_PROPSEG2 - PROPSEG value as defined in 18CXX8 ;* datasheet ;* (Must be between 1 thru 8) ;* m_Flags1 - Value of type enum CAN_CONFIG_FLAGS ;* ;* Output: CAN bit rate is set. All masks registers are set ;* '0' to allow all messages. ;* Filter registers are set according to flag value. ;* If (config & CAN_CONFIG_VALID_XTD_MSG) ;* Set all filters to XTD_MSG ;* Else if (config & CONFIG_VALID_STD_MSG) ;* Set all filters to STD_MSG ;* Else ;* Set half of the filters to STD while rests to ;* XTD_MSG. ;* ;* Side Effects: All pending transmissions are aborted. ;* ;**************************************************************************** CANInitializeFunc GLOBAL CANInitializeFunc ; Set configuration mode CANSetOperationMode CAN_OP_MODE_CONFIG ; call CANSetBaudRateFunc movlw CAN_CONFIG_MSG_BITS andwf m_Flags1,W movwf RXB0CON ;Load Rx Buffer 0 Control reg. btfsc m_Flags1,CAN_CONFIG_DBL_BUFFER_BIT_NO bsf RXB0CON,RXB0DBEN ;Set double Buffer Enable bit movff RXB0CON,RXB1CON ;Load same configuration in Rx Buffer 1 ;control register CANSetReg_IF CAN_MASK_B0, 0, m_Flags1 ;Set Mask B0 CANSetReg_IF CAN_MASK_B1, 0, m_Flags1 ;Set Mask B1 CANSetReg_IF CAN_FILTER_B0_F1, 0, m_Flags1 ;Set Filter 1 CANSetReg_IF CAN_FILTER_B0_F2, 0, m_Flags1 ;Set Filter 2 CANSetReg_IF CAN_FILTER_B1_F1, 0, m_Flags1 ;Set Filter 3 CANSetReg_IF CAN_FILTER_B1_F2, 0, m_Flags1 ;Set Filter 4 CANSetReg_IF CAN_FILTER_B1_F3, 0, m_Flags1 ;Set Filter 5 CANSetReg_IF CAN_FILTER_B1_F4, 0, m_Flags1 ;Set Filter 6 ; Restore to Normal mode. CANSetOperationMode CAN_OP_MODE_NORMAL ; banksel TxBufSize clrf TxBufSize ;Clear Tx Buffer data counter #ifdef CANIntLowPrior bsf RCON,IPEN ;Enable Priority levels on Int. movlw B'11100011' andwf IPR3,F ;Set low priority for Tx. Int. #else movlw B'00011100' iorwf IPR3,F ;Set high priority for Tx. Int. (Default) #endif bsf INTCON,GIE ;Enable global Interrupt bsf INTCON,PEIE ;Enable Peripheral Interrupt return ;**************************************************************************** ;* Function: void CANSetOperationModeFunc(CAN_OP_MODE mode) ;* ;* PreCondition: None ;* ;* Input: W reg - Operation mode code ;* ;* ;* Output: MCU is set to requested mode ;* ;* Side Effects: Databank is changed ;* ;* Overview: Given mode byte is copied to CANSTAT and made ;* sure that requested mode is set. ;* ;* Note: This is a blocking call. It will not return until ;* requested mode is set. ;**************************************************************************** CANSetOperationModeFunc GLOBAL CANSetOperationModeFunc movwf CANCON ;Request desired mode movwf Temp1 ;Store value in Temp reg. for future ChkModeSet: movlw CAN_OP_MODE_BITS andwf CANSTAT,W ;Chk CAN status register xorwf Temp1,W BSF STATUS,Z bnz ChkModeSet ;Wait till desired mode is set return ;**************************************************************************** ;* Function: void CANSetBaudRateFunc(BYTE SJW, ;* BYTE BRP, ;* BYTE PHSEG1, ;* BYTE PHSEG2, ;* BYTE PROPSEG, ;* enum CAN_CONFIG_FLAGS flags) ;* ;* PreCondition: MCU must be in Configuration mode or else these ;* values will be ignored. ;* ;* Input: m_SJW - SJW value as defined in 18CXX8 datasheet ;* (Must be between 1 thru 4) ;* m_BRP - BRP value as defined in 18CXX8 datasheet ;* (Must be between 1 thru 64) ;* m_PHSEG1 - PHSEG1 value as defined in 18CXX8 ;* datasheet ;* (Must be between 1 thru 8) ;* m_PHSEG2 - PHSEG2 value as defined in 18CXX8 ;* datasheet ;* (Must be between 1 thru 8) ;* m_PROPSEG - PROPSEG value as defined in 18CXX8 ;* datasheet ;* (Must be between 1 thru 8) ;* flags - Value of type enum CAN_CONFIG_FLAGS ;* ;* Output: CAN bit rate is set as per given values. ;* ;* Side Effects: Databank is changed ;* ;* Overview: Given values are bit adjusted to fit in 18CXX8 ;* BRGCONx registers and copied. ;* ;**************************************************************************** CANSetBaudRateFunc GLOBAL CANSetBaudRateFunc movff m_SJW,Temp1 decf Temp1,F ;Align values for offfset from 0 movlw 0x40 ;Multiply by 40H to align the bits mulwf Temp1 ;for BRGCON1 requirement movff PRODL,Temp1 ;Transfer Result to Temp1 movlw 0xc0 andwf Temp1,F ;Mask bits banksel m_BRP decf m_BRP,W ;Align values for offset from 0 iorwf Temp1,W ;Calculate value for BRGCON1 movwf BRGCON1 ;Transfer value to BRGCON1 movff m_PHSEG1,Temp1 decf Temp1,F rlncf Temp1,F ;Align the bits rlncf Temp1,F rlncf Temp1,W banksel m_PROPSEG2 decf m_PROPSEG2,F ;Align values for offset 0 iorwf m_PROPSEG2,W ;Calculate value for BRGCON2 movwf BRGCON2 ;Transfer value to BRGCON2 btfsc m_Flags1,CAN_CONFIG_PHSEG2_PRG_BIT_NO bsf BRGCON2,SEG2PHTS ;Set SEG2PHTS btfsc m_Flags1,CAN_CONFIG_SAMPLE_BIT_NO bsf BRGCON2,SAM ;Set SEG2PHTS movff m_PHSEG2,BRGCON3 ;Transfer PHSEG2 value to BRGCON3 decf BRGCON3,F btfsc m_Flags1,CAN_CONFIG_LINE_FILTER_BIT_NO bsf BRGCON3,WAKFIL ;Set WAKFIL bit return ;**************************************************************************** ;* Function: CANISetRegfunc RegAddr, ;* unsigned long val, ;* CAN_CONFIG_FLAGS type ;* ;* PreCondition: None ;* ;* Input: FSR0H:FSR0L - Starting address of a 32-bit buffer to ;* be updated ;* Reg1:Reg1+3 - 32-bit value to be converted ;* (Reg1= LL, Reg1+1 =LH, Reg1+2 = HL and Reg1+3 = HH ;* byte) ;* m_Flags1 - Type of message Flag - either ;* CAN_CONFIG_XTD_MSG or CAN_CONFIG_STD_MSG ;* ;* Output: Given CAN id value 'val' is bit adjusted and copied ;* into corresponding PIC18CXX8 CAN registers ;* ;* Side Effects: Databank changed ;* ;* Overview: If given id is of type standard identifier, ;* only SIDH and SIDL are updated ;* If given id is of type extended identifier, ;* bits val<17:0> is copied to EIDH, EIDL and SIDH<1:0> ;* bits val<28:18> is copied to SIDH and SIDL ;* ;**************************************************************************** CANSetRegFunc GLOBAL CANSetRegFunc banksel m_Flags1 btfss m_Flags1,CAN_CONFIG_MSG_TYPE_BIT_NO bra SetExtFram movlw 0x05 ;Rotetae Left 5 times the 32 bit number rcall RotateLeft32N movff Reg1+1,POSTINC0 banksel Reg1 movlw 0xe0 andwf Reg1,W movwf INDF0 return SetExtFram movlw 0x03 ;Rotetae Left 5 times the 32 bit number rcall RotateLeft32N movff Reg1+3,POSTINC0 ;Set EID<28:21> movff Reg1+2,INDF0 ;Set EID <20:18> movlw 0x03 ;Rotetae Right 5 times the 32 bit number rcall RotateRight32N ;to restore original number movlw 0xe0 ;Mask other bits except EID<20:18> andwf INDF0,F bsf INDF0,EXIDE ;Set EXIDE bit movlw 0x03 andwf Reg1+2,W iorwf POSTINC0,F ;Set EID<17:16> movff Reg1+1,POSTINC0 movff Reg1,POSTINC0 return ;**************************************************************************** ;* Function: RotateLeft32N ;* ;* ;* PreCondition: None ;* ;* Input: W reg: Value for total rotation required ;* ;* Reg1:Reg1+3 - 32-bit value to be converted ;* (Reg1= LL, Reg1+1 =LH, Reg1+2 = HL and Reg1+3 = HH ;* byte) ;* ;* Output: 32 bit value in Reg1 shifted left by value in W times ;* ;* Side Effects: Data Bank changed ;* ;* Overview: It shifts 32-bit value in Reg1 by W times and returns ;* result in Reg1 ;* ;**************************************************************************** RotateLeft32N banksel Reg1 RotateLMore: bcf STATUS,C btfsc Reg1+3,7 ;Pre-read bit 31 to be copied into bsf STATUS,C ;Bit 0 rlcf Reg1,F rlcf Reg1+1,F rlcf Reg1+2,F rlcf Reg1+3,F decfsz WREG,F bra RotateLMore return ;********************************************************************* ;* Function: CANIReadReg RegAddr, ;* Val, ;* CAN_CONFIG_FLAGS type ;* ;* PreCondition: None ;* ;* Input: FSR0 - Starting address of a 32-bit buffer to be ;* read ;* FSR1 - Starting address of a memory location to ;* copy read 32 bit value ;* m_Flags1 - Type of message - either ;* CAN_CONFIG_XTD_MSG or CAN_CONFIG_STD_MSG ;* ;* Output: Given CAN id value 'val' is bit adjusted and copied ;* into corresponding PIC18CXX8 CAN registers ;* ;* Side Effects: Databank changed ;* ;* Overview: If given id is of type standard identifier, ;* only SIDH and SIDL are read ;* If given id is of type extended identifier, ;* then EIDH and EIDL are read too to form 32 bit ;* value ;* ;********************************************************************/ CANReadRegFunc GLOBAL CANReadRegFunc movf POSTINC0,W ;To increment Pointer to point towards ;TxBnSIDL reg. btfsc POSTDEC0,EXIDE ;Check for Extended Fram bra ReadExtFram ;Yes Ext Frame, Read it. ;No, Standard Frame banksel Reg1 clrf Reg1+2 ;Set High Word to 00 for STD message clrf Reg1+3 movff POSTINC0,Reg1+1 ;Copy LH byte movff INDF0,Reg1 ;Save LL byte movlw 0x05 rcall RotateRight32N ;Rotate right for 5 times movlw 0x1f andwf Reg1+3,F ;Mask EID <31:28> bra CopyIDVal ReadExtFram banksel Reg1 movff POSTINC0,Reg1+3 ;Save EID <28:21> movff INDF0,Reg1+2 ;save EID<20:16> clrf Reg1+1 clrf Reg1 movlw 0x03 ;Position EID <28:18> rcall RotateRight32N ; movlw 0xfc ;Mask EID<17:16> andwf Reg1+2,F movlw 0x03 ;Mask all except EID<17:16> andwf POSTINC0,W iorwf Reg1+2,F movff POSTINC0,Reg1+1 ;Save EID<15:8> movff POSTINC0,Reg1 ;Save EID<7:0> CopyIDVal movff Reg1,POSTINC1 ;Return LL byte movff Reg1+1,POSTINC1 ;Return LH byte movff Reg1+2,POSTINC1 ;Return HL byte (What if EXt?) movff Reg1+3,POSTINC1 ;Return HH byte return ;**************************************************************************** ;* Function: RotateRight32N ;* ;* ;* PreCondition: None ;* ;* Input: W reg: Value for total rotation required ;* ;* Reg1:Reg1+3 - 32-bit value to be converted ;* (Reg1= LL, Reg1+1 =LH, Reg1+2 = HL and Reg1+3 = HH ;* byte) ;* ;* Output: 32 bit value in Reg1 shifted right by value in W times ;* ;* Side Effects: Data Bank changed ;* ;* Overview: It shifts 32-bit value in Reg1 by W times and returns ;* result in Reg1 ;* ;**************************************************************************** RotateRight32N banksel Reg1 RotateRMore: bcf STATUS,C btfsc Reg1,0 ;Pre-read bit 0 to be copied into bsf STATUS,C ;Bit 31 rrcf Reg1+3,F rrcf Reg1+2,F rrcf Reg1+1,F rrcf Reg1,F decfsz WREG,F bra RotateRMore return ;**************************************************************************** ;* Function: CANSendMessageFunc ;* ;* ;* PreCondition: None ;* ;* Input: Reg1<3:0> 32-bit Message ID ;* FSR1: starting address of data buffer ;* m_DataLength - Data Length ;* m_Flags - CAN_TX_MSG_FLAGS type ;* ;* Output: W reg = 0, If buffer is Full ;* W reg = 1, If successful ;* ;* Side Effects: Databank changed ;* ;* Overview: It copies the data in available hardware or software ;* buffer. If present data is of higher priority then ;* the data in hardware buffer then it aborts ;* transmission of lowest priority data in HW buffer and ;* copies it to SW buffer and copies present data to HW ;* Buffer for immediate transmission ;* ;**************************************************************************** CANSendMessageFunc GLOBAL CANSendMessageFunc banksel TxBufSize movf TxBufSize,W xorlw TxBufMaxSize bnz BufEmpty retlw 0x00 ;Send Error Code that Buffer is full BufEmpty: clrf TxFlags ;Clear Buf set flags movlw 0x03 subwf TxBufSize,W bnc LoadHWBuf goto LoadSWBuf LoadHWBuf: banksel TXB0CON btfsc TXB0CON,TXREQ,BANKED bra ChkNxtHWBuf1 movlw low(TXB0SIDH) movwf FSR0L ;Save the address of destination register movlw high(TXB0SIDH) movwf FSR0H bsf TxFlags,CANTxBuf0Flag ;Indicate Buf 0 Set bra CopyBufData ChkNxtHWBuf1: banksel TXB1CON btfsc TXB1CON,TXREQ, BANKED bra ChkNxtHWBuf2 movlw low(TXB1SIDH) movwf FSR0L ;Save the address of destination register movlw high(TXB1SIDH) movwf FSR0H bsf TxFlags,CANTxBuf1Flag ;Indicate Buf 1 Set bra CopyBufData ChkNxtHWBuf2: banksel TXB2CON btfsc TXB2CON,TXREQ, BANKED bra CopyBufData ; What ? movlw low(TXB2SIDH) movwf FSR0L ;Save the address of destination register movlw high(TXB2SIDH) movwf FSR0H bsf TxFlags,CANTxBuf2Flag ;Indicate Buf 2 set CopyBufData: nop SaveFSR0 ;FSR0 contains starting address of Reg to be read SaveFSR1 ;FSR1 contains starting address of Data Buffer CANSetReg_PREG_DV_IF m_TxFlags ;Copy ID value in corresponding Regs. RestoreFSR0 RestoreFSR1 movlw 0x04 ;Point towards TXBnDLC reg. movff m_DataLength,PLUSW0 btfss m_Flags1,CAN_TX_RTR_BIT_NO bsf PLUSW0,TXRTR incf WREG ;Point towards TxBnD0 addwf FSR0L,F ;Add W value into FSR0 to find movlw 0x00 addwfc FSR0H,F ;new pointer value in FSR for TxBnD0 banksel m_DataLength movf m_DataLength,W ;Data Length Counter to copy all data CopyNxtTxData: movff POSTINC1,POSTINC0 MOVLW 0x1 movwf WREG decfsz WREG ;All data copied? bra CopyNxtTxData ;No, Copy next data DisableInt ;Disable Interrupt occurrence banksel TxBufSize incf TxBufSize ;Indicate new Buffer size btfss TxFlags,CANTxSoftBufFlag bra HWBufAnal ;This section checks for higher priority message in SW buffer than the HW ;buffer. If SW buf contains higher priority message then it Aborts the ;Transmission of lowest priority message in HW buf and Exchanges the data call FindPriorSWBuf ;Returns Highest Priority buffer number in ;Temp2 and Data in Temp32Data+4 banksel TXB0CON movlw 0x03 andwf TXB0CON,W,BANKED bnz ChkBuf1 CANReadReg CAN_TX_IDB0, Temp32Data+4 ; call Cmp32Bit ;Check if SW buffer priority is higher than bc HWBufAnal ;TxBuf0 Priority banksel TXB0CON bcf TXB0CON,TXREQ,BANKED ;If yes, Request Abort WaitAbort0: btfsc PIR3,TXB0IF ;If TxBuf0 is transmitting then TxBuf0 Empty? bra TxBuf0Emptied btfss TXB0CON,TXABT,BANKED ;Message Aborted? bra WaitAbort0 bra TxB0Abtd ;Message was successfully Aborted TxBuf0Emptied: bcf PIR3,TXB0IF ;If TxBuf has finished the Transmission of bcf PIE3,TXB0IE ;current message than decrease buffer size banksel TxBufSize decf TxBufSize,F TxB0Abtd: movlw low(TXB0SIDH) movwf FSR0L movlw high(TXB0SIDH) movwf FSR0H call ExchangeBuffers ;Xchng highest priority SW Buffer data banksel TXB0CON ;with Tx Buffer 0 and bsf TXB0CON,TXREQ,BANKED ;Request Transmission bra HWBufAnal ChkBuf1: banksel TXB1CON movlw 0x03 andwf TXB1CON,W,BANKED bnz ChkBuf2 CANReadReg CAN_TX_IDB1, Temp32Data+4 ; call Cmp32Bit ;Check if SW Buf priority is higher than bc HWBufAnal ;TxBuf1 banksel TXB1CON bcf TXB1CON,TXREQ,BANKED ;If yes, Request Abort WaitAbort1: btfsc PIR3,TXB1IF ;TxBuf0 Empty? bra TxBuf1Emptied btfss TXB1CON,TXABT,BANKED ;Message Aborted? bra WaitAbort1 bra TxB1Abtd ;Message was successfully Aborted TxBuf1Emptied: bcf PIR3,TXB1IF ;If TxBuf has finished the Transmission of bcf PIE3,TXB1IE ;current message than decrease buffer size banksel TxBufSize decf TxBufSize,F TxB1Abtd: movlw low(TXB1SIDH) movwf FSR0L movlw high(TXB1SIDH) movwf FSR0H call ExchangeBuffers ;Exchange highest priority SW buffer banksel TXB1CON ;data with Tx Buffer 1 and bsf TXB1CON,TXREQ,BANKED ;Request Transmission bra HWBufAnal ChkBuf2: banksel TXB2CON movlw 0x03 andwf TXB2CON,W,BANKED bnz HWBufAnal CANReadReg CAN_TX_IDB2, Temp32Data+4 ;, m_TxFlags call Cmp32Bit ;Check if SW buffer priority is higher than bc HWBufAnal ;TxBuf2 banksel TXB2CON bcf TXB2CON,TXREQ,BANKED ;If yes, Request Abort WaitAbort2: btfsc PIR3,TXB2IF ;TxBuf0 Empty? bra TxBuf2Emptied btfss TXB2CON,TXABT,BANKED ;Message Aborted? bra WaitAbort2 bra TxB2Abtd ;Message was successfully Aborted TxBuf2Emptied: bcf PIR3,TXB2IF ;If TxBuf has finished the transmission of bcf PIE3,TXB2IE ;current message then decrease Buffer Size banksel TxBufSize decf TxBufSize,F TxB2Abtd: movlw low(TXB2SIDH) movwf FSR0L movlw high(TXB2SIDH) movwf FSR0H call ExchangeBuffers ;Exchange Highest priority SW buf data banksel TXB2CON ;with TxBuf2 and bsf TXB2CON,TXREQ,BANKED ;Request Transmission HWBufAnal: rcall SetHWBufPrior EnableInt retlw 0x01 ;Return success Code LoadSWBuf: mullw D'14' ;Buffer size in bytes movf PRODL,W ;Get low byte of result in W reg addlw low(TxBuffer) movwf FSR0L ;Find Starting address of Soft. Buffer clrf FSR0H movlw high(TxBuffer) addwfc FSR0H,F bsf TxFlags,CANTxSoftBufFlag bra CopyBufData ;**************************************************************************** ;* Function: SetHWBufPrior ;* ;* ;* PreCondition: None ;* ;* Input: None ;* ;* ;* Output: It sets the priority of all HW Tx Buffer depending on ;* the Message ID in Buffer. Lower the ID value higher ;* the priority ;* ;* ;* Side Effects: Databank changed ;* ;* Overview: It sets the CAN TX HW Buffer priority depending on the ;* CAN ID in buffer. ;* ;* ;**************************************************************************** SetHWBufPrior banksel TXB0CON movlw 0xfc andwf TXB0CON,F,BANKED ;Set Priority level 0 for TxBuf-0 banksel TXB1CON andwf TXB1CON,F,BANKED ;Set Priority level 0 for TxBuf-1 banksel TXB2CON andwf TXB2CON,F,BANKED ;Set Priority level 0 for TxBuf-2 CANReadReg CAN_TX_IDB0, Temp32Data ; CANReadReg CAN_TX_IDB1, Temp32Data+4 ; rcall Cmp32Bit btfsc STATUS,C bra Buf1HighPrior banksel TXB0CON incf TXB0CON,F,BANKED bra NxtCompare1 Buf1HighPrior: banksel TXB1CON incf TXB1CON,F,BANKED NxtCompare1: CANReadReg CAN_TX_IDB0, Temp32Data ; CANReadReg CAN_TX_IDB2, Temp32Data+4 ; rcall Cmp32Bit btfsc STATUS,C bra Buf2HighPrior banksel TXB0CON incf TXB0CON,F,BANKED bra NxtCompare2 Buf2HighPrior: banksel TXB2CON incf TXB2CON,F,BANKED NxtCompare2: CANReadReg CAN_TX_IDB1, Temp32Data ; CANReadReg CAN_TX_IDB2, Temp32Data+4 ; rcall Cmp32Bit btfsc STATUS,C bra Buf2HighPrior1 banksel TXB1CON incf TXB1CON,F,BANKED bra NxtCompare3 Buf2HighPrior1: banksel TXB2CON incf TXB2CON,F,BANKED NxtCompare3: btfss TxFlags,CANTxBuf0Flag bra SetNxtBuf1 banksel TXB0CON bsf TXB0CON,TXREQ, BANKED bsf PIE3,TXB0IE ;Enable TxBuf0 Int. SetNxtBuf1: btfss TxFlags,CANTxBuf1Flag bra SetNxtBuf2 banksel TXB1CON bsf TXB1CON,TXREQ, BANKED bsf PIE3,TXB1IE ;Enable TxBuf0 Int. SetNxtBuf2: btfss TxFlags,CANTxBuf2Flag bra SetNxtBuf3 banksel TXB2CON bsf TXB2CON,TXREQ, BANKED bsf PIE3,TXB2IE ;Enable TxBuf0 Int. SetNxtBuf3: return ;**************************************************************************** ;* Function: Cmp32Bit ;* ;* ;* PreCondition: None ;* ;* Input: Temp32Data - 32-bit data 1 ;* Temp32Data + 4 - 32-bit Data -2 ;* ;* Output: If Data 1 = Data 2 C =1, Z=1 ;* If Data 1 > Data 2 C =1, Z=0 ;* If Data 1 < Data 2 C =0, Z=0 ;* ;* ;* Side Effects: Databank changed ;* ;* Overview: It compares two 32-bit data and sets the Flag ;* accordingly. ;* ;* ;**************************************************************************** Cmp32Bit banksel Temp32Data movf Temp32Data+4,w subwf Temp32Data,W movf Temp32Data+5,w subwfb Temp32Data+1,W movf Temp32Data+6,w subwfb Temp32Data+2,W movf Temp32Data+7,w subwfb Temp32Data+3,W return ;**************************************************************************** ;* Function: FindPriorSWBuf ;* ;* PreCondition: None ;* ;* Input: None ;* ;* Output: Max. Priority buffer number into Temp2 ;* ;* Side Effects: Databank changed ;* ;* Overview: It finds highest priority Message Buffer number ;* ;**************************************************************************** FindPriorSWBuf clrf Temp3 ;Clear Buffer Counter banksel Temp32Data setf Temp32Data ;+4 ;Initialize Maximum data to 0 setf Temp32Data+1 ;+5 setf Temp32Data+2 ;+6 setf Temp32Data+3 ;+7 ChkNxtBufID: movf Temp3,W mullw D'14' ;Buffer size in bytes movf PRODL,W ;Get result in W addlw low(TxBuffer) movwf FSR0L ;Find Starting address of Soft. Buffer clrf FSR0H movlw high(TxBuffer) addwfc FSR0H,F ; CANReadReg_PREG Temp32Data+4, CAN_CONFIG_XTD_MSG CANReadReg_PREG Temp32Data+4 rcall Cmp32Bit bnc PrsntDataBig movff Temp32Data+4 ,Temp32Data ;Present Data is ;bigger so movff Temp32Data+5 ,Temp32Data+1 ;save it for next comparison movff Temp32Data+6 ,Temp32Data+2 movff Temp32Data+7 ,Temp32Data+3 movff Temp3,Temp2 ;Save software Buffer Number PrsntDataBig: incf Temp3,F movf Temp3,W addlw 0x03 banksel TxBufSize xorwf TxBufSize,W bnz ChkNxtBufID return ;**************************************************************************** ;* Function: ArrangeBuffers ;* ;* PreCondition: None ;* ;* Input: FSR0 - Starting address of buffer 1 ;* Temp2 - SW buffer number to start sorting ;* ;* Output: It copies buffer n+1 data to buffer n ;* It starts with the buffer number passed in Temp2 ;* and ends at highest buffer ;* ;* Side Effects: Databank changed ;* ;* Overview: It arranges the data in Software buffer for next ;* transmission. ;* ;**************************************************************************** ArrangeBuffers ; clrf Temp2 ;Temp2 contains Buffer start number ;Clear if want to start with Buf 0 to make ;FIFO XchngNxtBuf: movf Temp2,W mullw D'14' ;Buffer size in bytes movf PRODL,W ;Get result in W addlw low(TxBuffer) movwf FSR0L ;Find Starting address of present Soft. Buffer clrf FSR0H movlw high(TxBuffer) addwfc FSR0H,F incf Temp2,F movf Temp2,W addlw 0x03 banksel TxBufSize subwf TxBufSize,W ;Check if Max. Buf size has been reached bnc EndXchng ;Yes, then end exchanging ; bz EndXchng movf Temp2,W mullw D'14' ;Buffer size in bytes movf PRODL,W ;Get result in W addlw low(TxBuffer) movwf FSR1L ;Find Starting address of next Soft. Buffer clrf FSR1H movlw high(TxBuffer) addwfc FSR1H,F movlw D'13' XchngNxtData: movff POSTINC1,POSTINC0 decfsz WREG bra XchngNxtData bra XchngNxtBuf EndXchng: return ;**************************************************************************** ;* Function: ExchangeBuffers ;* ;* PreCondition: None ;* ;* Input: FSR0 - Starting address of buffer 1 ;* Temp2 - SW buffer number ;* ;* Output: ;* ;* Side Effects: None ;* ;* Overview: It exchanges the data in Buffer pointed by FSR0 and ;* Software buffer (number in Temp2). ;* ;**************************************************************************** ExchangeBuffers movf Temp2,W mullw D'14' ;Buffer size in bytes movf PRODL,W ;Get result in W addlw low(TxBuffer) movwf FSR1L ;Find Starting address of Soft. Buffer clrf FSR1H movlw high(TxBuffer) addwfc FSR1H,F movlw D'13' XchngNxtData1: movff INDF0,Temp1 movff INDF1,POSTINC0 movff Temp1,POSTINC1 decfsz WREG bra XchngNxtData1 return ;**************************************************************************** ;* Function: CANReadMessageFunc ;* ;* PreCondition: None ;* ;* Input: None ;* ;* Output: W reg =0, If no data is pending ;* W reg= 1, If data is available ;* ;* Side Effects: None ;* ;* Overview: It formats the data in Rx Buffer and returns it. ;* It stores 32-bit Message ID, Recd. data, Data Length ;* and Receiver Status Flags into user supplied memory ;* locations. ;* ;***************************************************************************** CANReadMessageFunc GLOBAL CANReadMessageFunc SaveFSR0 banksel m_RxFlags clrf m_RxFlags btfss RXB0CON,RXFUL bra ChkRxBuf1 movlw B'11110001' andwf CANCON,F ;Select WIN bits for buffer 0 bcf PIR3,RXB0IF ;Clear flag indicating new message in Buf 0 btfss COMSTAT,RXB0OVFL ;Check for Buf 0 Overflow bra B0NotOvrFlow bsf m_RxFlags,CAN_RX_OVERFLOW_BIT_NO B0NotOvrFlow: btfsc RXB0CON ,FILHIT0 bsf m_RxFlags,CAN_RX_FILTER_1_BIT_NO bra CopyBuffer ChkRxBuf1: banksel RXB1CON btfss RXB1CON,RXFUL,BANKED bra ReturnRxErrCode ;Return Error code movlw B'11110001' andwf CANCON,F ;Select WIN bits for buffer 1 movlw B'00001010' ; iorwf CANCON,F ; bcf PIR3,RXB1IF ;Clear flag indicating new message in Buf 0 banksel m_RxFlags btfss COMSTAT,RXB1OVFL ;Check for Buf 0 Overflow bra B1NotOvrFlow bsf m_RxFlags,CAN_RX_OVERFLOW_BIT_NO B1NotOvrFlow: movlw CAN_RX_FILTER_BITS andwf RXB0CON,W ;Because of WIN bits accessing RXB1CON iorwf m_RxFlags ;Store the Acceptance filter value into ;Rx_Flags movlw 0xf8 ;Mask all bits except 3 LSB's andwf RXB0CON,W ;And with RXB1CON sublw 0x02 ;Whether Filter 0 or 1 caused hit bz CopyBuffer ;No, Then copy buffer data bnc CopyBuffer bsf m_RxFlags,CAN_RX_DBL_BUFFERED_BIT_NO CopyBuffer: movlw 0x0f andwf RXB0DLC,W ;Depending on the WIN bits actual register ;will be accessed. banksel m_DataLength movwf m_DataLength ;copy Data length value into register banksel m_RxFlags btfsc RXB0CON,RXRTRRO ;Check for Remote Frame bit bsf m_RxFlags,CAN_RX_RTR_FRAME_BIT_NO btfsc RXB0SIDL,EXID ;Check for Remote Frame bit bsf m_RxFlags,CAN_RX_XTD_FRAME_BIT_NO movff FSR0L,TFSR1 ;Transfer data in Temp. reg. for FSR1 movff FSR0H,TFSR1+1 movlw low(RXB0SIDH) ;Point towards starting address of ID movwf FSR0L movlw high(RXB0SIDH) movwf FSR0H CANReadReg_PREG Temp32Data ;, CAN_CONFIG_XTD_MSG RestoreFSR1 ;Get source data pointer in FSR1 movlw low(RXB0D0) ;Point towards starting address of ID movwf FSR0L movlw high(RXB0D1) movwf FSR0H banksel m_DataLength movf m_DataLength,w CopyNxtRxData: movff POSTINC0,POSTINC1 decfsz WREG bra CopyNxtRxData bcf RXB0CON,RXFUL ;Indicate that buffer is open to receive Msg. movlw B'11110001' andwf CANCON,F ;Select default WIN bits btfss PIR3,IRXIF ;Check for any invalid message occurrence on bra NoInvldMsg ;the CAN bus bcf PIR3,IRXIF banksel m_RxFlags ;Return Invalid message flag bit bsf m_RxFlags,CAN_RX_INVALID_MSG_BIT_NO NoInvldMsg: retlw 0x01 ;Return Success code ReturnRxErrCode: retlw 0x00 ;Return Error Code ;**************************************************************************** ;* Function: CANISR ;* ;* PreCondition: None ;* ;* Input: None ;* ;* Output: None ;* ;* Side Effects: None ;* ;* Overview: If any data is pending for transmission then it will ;* copy highest priority data in Empty buffer and ;* requests Transmission. ;* ;**************************************************************************** CANISR GLOBAL CANISR movlw B'00011100' ;If all Tx interrupts are disabled andwf PIR3,W bz EndCANISR ;then End ISR call SaveWorkRegs clrf TxFlags btfss PIR3,TXB0IF ;TxBuf0 Empty? bra ChkTxBuf1Int bcf PIR3,TXB0IF bcf PIE3,TXB0IE bsf TxFlags,CANTxBuf0Flag call FindPriorSWBuf ;Returns Highest Priority buffer number in ;Temp2 and Data in Temp32Data+4 movlw low(TXB0SIDH) movwf FSR0L movlw high(TXB0SIDH) movwf FSR0H bra BufSet ChkTxBuf1Int: btfss PIR3,TXB1IF ;TxBuf1 Empty? bra ChkTxBuf2Int bcf PIR3,TXB1IF bcf PIE3,TXB1IE bsf TxFlags,CANTxBuf1Flag call FindPriorSWBuf ;Returns Highest Priority buffer number in ;Temp2 and Data in Temp32Data+4 movlw low(TXB1SIDH) movwf FSR0L movlw high(TXB1SIDH) movwf FSR0H bra BufSet ChkTxBuf2Int: btfss PIR3,TXB2IF ;TxBuf2 Empty? bra NoBufEmpty bcf PIR3,TXB2IF bcf PIE3,TXB2IE bsf TxFlags,CANTxBuf2Flag call FindPriorSWBuf ;Returns Highest Priority buffer number in ;Temp2 and Data in Temp32Data+4 movlw low(TXB2SIDH) movwf FSR0L movlw high(TXB2SIDH) movwf FSR0H BufSet: movlw 0x03 ;Check whether any data is pending in Buffer banksel TxBufSize decf TxBufSize,F subwf TxBufSize,W bc BufPending bz BufPending bra NoBufEmpty BufPending: call ExchangeBuffers rcall SetHWBufPrior call ArrangeBuffers NoBufEmpty: rcall RestoreWorkRegs EndCANISR return ;**************************************************************************** ;* Function: SaveWorkRegs ;* ;* PreCondition: None ;* ;* Input: None ;* ;* Output: None ;* ;* Side Effects: None ;* ;* Overview: It saves all GPR registers used by different functions ;* in Temp. locations. ;* ;**************************************************************************** SaveWorkRegs movff Temp32Data,ITemp32Data ;Save Temp32Data movff Temp32Data+1,ITemp32Data+1 movff Temp32Data+2,ITemp32Data+2 movff Temp32Data+3,ITemp32Data+3 movff Temp32Data+4,ITemp32Data+4 movff Temp32Data+5,ITemp32Data+5 movff Temp32Data+6,ITemp32Data+6 movff Temp32Data+7,ITemp32Data+7 movff Reg1,IReg1 ;Save Reg1 movff Reg1+1,IReg1+1 movff Reg1+2,IReg1+2 movff Reg1+3,IReg1+3 movff m_TxFlags,Im_TxFlags movff TxFlags,ITxFlags movff Temp1,ITemp1 ;Save Temp1 movff Temp2,ITemp2 ;Save Temp2 movff Temp3,ITemp3 ;Save Temp3 movff FSR0L,IFSR0 ;Save FSR 0 movff FSR0H,IFSR0+1 movff FSR1L,IFSR1 ;Save FSR 1 movff FSR1H,IFSR1+1 return ;**************************************************************************** ;* Function: RestoreWorkRegs ;* ;* PreCondition: None ;* ;* Input: None ;* ;* Output: None ;* ;* Side Effects: None ;* ;* Overview: It saves all GPR registers used by different functions ;* in Temp. locations. ;* ;**************************************************************************** RestoreWorkRegs movff ITemp32Data,Temp32Data ;Restore Temp32Data movff ITemp32Data+1,Temp32Data+1 movff ITemp32Data+2,Temp32Data+2 movff ITemp32Data+3,Temp32Data+3 movff ITemp32Data+4,Temp32Data+4 movff ITemp32Data+5,Temp32Data+5 movff ITemp32Data+6,Temp32Data+6 movff ITemp32Data+7,Temp32Data+7 movff IReg1,Reg1 ;Restore Reg1 movff IReg1+1,Reg1+1 movff IReg1+2,Reg1+2 movff IReg1+3,Reg1+3 movff ITxFlags,TxFlags movff Im_TxFlags,m_TxFlags movff ITemp1,Temp1 ;Restore Temp1 movff ITemp2,Temp2 ;Restore Temp2 movff ITemp3,Temp3 ;Restore Temp3 movff IFSR0,FSR0L ;Restore FSR 0 movff IFSR0+1,FSR0H movff IFSR1,FSR1L ;Restore FSR 1 movff IFSR1+1,FSR1H return ;***************************************************************************** ;* Function: CANIsTxPassive() ;* ;* PreCondition: None ;* ;* Input: None ;* ;* Output: C = 1, if CAN transmit module is error passive as ;* defined by CAN specifications. ;* C = 0, if CAN transmit module is in active state ;* Side Effects: None ;* ;***************************************************************************** CANIsTxPassive bcf STATUS,C btfsc COMSTAT,TXBP bsf STATUS,C ;If Bus is in Tx passive state, set C return ;***************************************************************************** ;* Function: CANIsRxPassive() ;* ;* PreCondition: None ;* ;* Input: None ;* ;* Output: C = 1, if CAN receive module is error passive as ;* defined by CAN specifications. ;* C = 0, if CAN receive module is in active state ;* Side Effects: None ;* ;***************************************************************************** CANIsRxPassive bcf STATUS,C btfsc COMSTAT,RXBP bsf STATUS,C ;If Bus is in Rx passive state, set C return ;***************************************************************************** ;* Function: CANIsBusOff() ;* ;* PreCondition: None ;* ;* Input: None ;* ;* Output: C = 1, if CAN transmit module is in Bus Off state as ;* defined by CAN specifications. ;* C = 0, if CAN module is not in bus Off state ;* Side Effects: None ;* ;***************************************************************************** CANIsBusOff GLOBAL CANIsBusOff bcf STATUS,C btfsc COMSTAT,TXBO bsf STATUS,C ;If Bus is in off state, set C return ;**************************************************************************** ;* Function: BOOL CANIsRxReady() ;* ;* PreCondition: None ;* ;* Input: None ;* ;* Output: C=1, If one of the receive buffer is empty ;* C=0, If none of the receive buffer is empty. ;* ;* Side Effects: Data banks changed ;* ;**************************************************************************** CANIsRxReady GLOBAL CANIsRxReady bcf STATUS,C btfsc RXB0CON,RXFUL bsf STATUS,C ;If buffer is empty than set carry to ;indicate banksel RXB1CON btfsc RXB1CON,RXFUL,BANKED bsf STATUS,C return ;**************************************************************************** ;* Macro: BOOL CANIsTxReady() ;* ;* PreCondition: None ;* ;* Input: None ;* ;* Output: C=1, If at least one CAN transmit buffer is empty ;* C=0, If all CAN transmit buffers are full ;* ;* Side Effects: Databank changed ;* ;**************************************************************************** CANIsTxReady GLOBAL CANIsTxReady banksel TxBufSize movf TxBufSize,W sublw TxBufMaxSize bnz TxReady1 bcf STATUS,C ; TxReady1: return END