' Program HBUS.INC ' HBUSIN amd HBUSOUT macros ' Using the Master Synchronous Serial Port (MSSP). Configured as an I2C master. ' The Eread and Ewrite subroutines, as well as the individual I2C conditions, are written in assembler for more efficiency. ' ** Declare some SYSTEM Variables ** GEN Var Word SYSTEM ' 16-bit address of eeprom PP0 Var Byte SYSTEM ' 8-bit Slave address PP0H Var Byte SYSTEM ' Byte to access eeprom ' Configure the SSP for master I2C mode ' TRISC.3 = 1 ' Make Portc.3 an input (SCL) ' TRISC.4 = 1 ' Make Portc.4 an input (SDA) SSPSTAT = %01000000 ' Disable the slew rate for normal 100khz operation ' Set the input levels to conform to I2C specs SSPADD = ((XTAL * 1000) / (100 * 4)) - 1 ' Calculate the Baud rate value for SSPADD SSPCON = %00101000 ' I2C master mode selected and Enable the SSP Goto Over_SSP_Subs ' Jump over rhe subroutines '----------------------------------------------------------------------------------------------- ' Create the HBUSIN and HBUSOUT macros HBUSOUT MACRO SLAVE_ADDRESS , ADDRESS , Byteout1 #if (PRM_1 == BYTE) Byte_Byte SLAVE_ADDRESS , PP0 #endif #if (PRM_1 == WORD) Byte_Byte SLAVE_ADDRESS , PP0 #endif #if ((PRM_1 == NUM8) || (PRM_1 == NUM16)) Num_Byte SLAVE_ADDRESS , PP0 #endif #if (PRM_2 == BYTE) Byte_Word ADDRESS , GEN #endif #if (PRM_2 == WORD) Word_Word ADDRESS , GEN #endif #if ((PRM_2 == NUM8) || (PRM_1 == NUM16)) Num_Word ADDRESS , GEN #endif #if(PRM_C >= 3) Call EEREAD #if (PRM_3 == BIT) Byte_Bit Byteout1,PP0H #endif #if (PRM_3 == BYTE) Byte_Byte Byteout1,PP0H #endif #if (PRM_3 == WORD) Byte_Word Byteout1,PP0H #endif Call EEWRITE #endif ENDM HBUSIN MACRO SLAVE_ADDRESS , ADDRESS , Bytein1 #if (PRM_1 == BYTE) Byte_Byte SLAVE_ADDRESS , PP0 #endif #if (PRM_1 == WORD) Byte_Byte SLAVE_ADDRESS , PP0 #endif #if ((PRM_1 == NUM8) || (PRM_1 == NUM16)) Num_Byte SLAVE_ADDRESS , PP0 #endif #if (PRM_2 == BYTE) Byte_Word ADDRESS , GEN #endif #if (PRM_2 == WORD) Word_Word ADDRESS , GEN #endif #if ((PRM_2 == NUM8) || (PRM_1 == NUM16)) Num_Word ADDRESS , GEN #endif #if(PRM_C >= 3) Call EEREAD #if (PRM_3 == BIT) Byte_Bit PP0H , Bytein1 #endif #if (PRM_3 == BYTE) Byte_Byte PP0H , Bytein1 #endif #if (PRM_3 == WORD) Byte_Word PP0H , Bytein1 #endif #endif ENDM '----------------------------------------------------------------------------------------------- ' ** ASSEMBLER SUBROUTINES ** '----------------------------------------------------------------------------------------------- Asm ;************************** ;* Generate an I2C START * ;************************** Send_Start Bsf STATUS,RP0 ; Point to register Bank1 Bsf SSPCON2,SEN ; Send a start condition #if (WATCHDOG_REQ == 1) Clrwdt Btfsc SSPCON2,SEN ; Wait for the Start condition to end Goto $ - 2 #else Btfsc SSPCON2,SEN ; Wait for the Start condition to end Goto $ - 1 #endif Bcf STATUS,RP0 ; Point back to register Bank0 Return ;----------------------------------------------------------------------------------------------- ;************************** ;* Generate an I2C STOP * ;************************** Send_Stop Bsf STATUS,RP0 ; Point to register Bank1 Bsf SSPCON2,PEN ; Send a start condition #if (WATCHDOG_REQ == 1) Clrwdt Btfsc SSPCON2,PEN ; Wait for the Stop condition to end Goto $ - 2 #else Btfsc SSPCON2,PEN ; Wait for the Stop condition to end Goto $ - 1 #endif Bcf STATUS,RP0 ; Point back to register Bank0 Return ;----------------------------------------------------------------------------------------------- ;*************************** ;* Generate an I2C RESTART * ;*************************** Send_Restart Bsf STATUS,RP0 ; Point to register Bank1 Bsf SSPCON2,RSEN ; Send a repeat start condition #if (WATCHDOG_REQ == 1) Clrwdt Btfsc SSPCON2,RSEN ; Wait for the Restart condition to end Goto $ - 2 #else Btfsc SSPCON2,RSEN ; Wait for the Restart condition to end Goto $ - 1 #endif Bcf STATUS,RP0 ; Point back to register Bank0 Return ;----------------------------------------------------------------------------------------------- ;*************************** ;* Generate an I2C NACK * ;*************************** Send_NACK Bsf STATUS,RP0 ; Point to register Bank1 Bsf SSPCON2,ACKDT ; Sent the NACK condition Bsf SSPCON2,ACKEN #if (WATCHDOG_REQ == 1) Clrwdt Btfsc SSPCON2,ACKEN ; Check if we are in idle mode Goto $ - 2 #else Btfsc SSPCON2,ACKEN ; Check if we are in idle mode Goto $ - 1 #endif Bcf STATUS,RP0 ; Point back to register Bank0 Return ;----------------------------------------------------------------------------------------------- ;*********************** ;* Send a byte via I2C * ;* Send the contents * ;* of the W reg * ;*********************** Out_Byte Movwf SSPBUF ; Place the byte to output into the buffer Bsf STATUS,RP0 ; Point to register Bank1 #if (WATCHDOG_REQ == 1) Clrwdt Btfsc SSPSTAT,R_W ; Check if data transmit is complete Goto $ - 2 ;Clrwdt ;Btfsc SSPCON2,ACKSTAT ; Check if acknowledge was received ;Goto $ - 2 #else Btfsc SSPSTAT,R_W ; Check if data transmit is complete Goto $ - 1 ;Btfsc SSPCON2,ACKSTAT ; Check if acknowledge was received ;Goto $ - 1 #endif Bcf STATUS,RP0 ; Point back to register Bank0 Return ;----------------------------------------------------------------------------------------------- ;************************** ;* Receive a byte via I2C * ;* The byte received is * ;* held in the W reg * ;************************** In_Byte Bsf STATUS,RP0 ; Point to register Bank1 Bsf SSPCON2,RCEN ; Send Receive condition #if (WATCHDOG_REQ == 1) Clrwdt Btfsc SSPCON2,RCEN Goto $ - 2 Clrwdt Btfss SSPSTAT,BF ; Wait for buffer to fill up Goto $ - 2 #else Btfsc SSPCON2,RCEN Goto $ - 1 Btfss SSPSTAT,BF ; Wait for buffer to fill up Goto $ - 1 #endif Bcf STATUS,RP0 ; Point back to register Bank0 Movfw SSPBUF ; Place the buffer into W Return ;----------------------------------------------------------------------------------------------- ;*********************** ;* Send the 16-bit * ;* address via I2C * ;*********************** Send_Address Call Send_Start ; Send a START condition Bcf PP0,0 ; Set the R/W bit to WRITE Movfw PP0 ; Send the device+slave address+ WRITE bit Call Out_Byte Movfw GENH ; Send the highbyte of the 16-bit address Call Out_Byte Movfw GEN ; Send the lowbyte of the 16-bit address Call Out_Byte Return Endasm '----------------------------------------------------------------------------------------------- ' Write a single byte to the Eeprom ' The address is held in the variable "GEN" ' The byte to be written is held in the variable "PP0H" EEWrite: TRISC.3 = 1 ; Make Portc.3 an input (SCL) TRISC.4 = 1 ; Make Portc.4 an input (SDA) Asm Call Send_Address ; Send the Start, slave address, and memory address Movfw PP0H ; Send the byte to be placed within the eeprom Call Out_Byte Call Send_Stop ; Send a STOP condition Endasm Return ' Basic RETURN command '----------------------------------------------------------------------------------------------- ' Read a single byte from the Eeprom ' The address is held in the variable "GEN" ' The byte read is returned in the variable "PP0H" EERead: TRISC.3 = 1 ; Make Portc.3 an input (SCL) TRISC.4 = 1 ; Make Portc.4 an input (SDA) Asm Call Send_Address ; Send the Start, slave address, and memory address Call Send_Restart ; Send a Restart condition Bsf PP0,0 ; Set the R/W bit to READ Movfw PP0 Call Out_Byte ; Send the device+slave address+ READ bit Call In_Byte ; Read the byte from the eeprom (returned in E_BYTEIN) Movwf PP0H ; Place the buffer into E_Bytein Call Send_NACK ; Send a NACK condition (to release the SDA line) Call Send_Stop ; Send a STOP condition Endasm Return '----------------------------------------------------------------------------------------------- ' Make sure the HBUS library fits in the first page Asm if ($ >= H'0800') ERROR "HBUS has exceeded page 0." endif Endasm Over_SSP_Subs: