Mercurial > public > mk2
view code_part1/OSTC_code_asm_part1/i2c_eeprom.asm @ 760:e16e636def61
2.74 release
author | heinrichsweikamp |
---|---|
date | Sun, 01 Dec 2013 10:33:12 +0100 |
parents | 16f4eafc197e |
children | c50296c3059e |
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; OSTC - diving computer code ; Copyright (C) 2008 HeinrichsWeikamp GbR ; This program is free software: you can redistribute it and/or modify ; it under the terms of the GNU General Public License as published by ; the Free Software Foundation, either version 3 of the License, or ; (at your option) any later version. ; This program is distributed in the hope that it will be useful, ; but WITHOUT ANY WARRANTY; without even the implied warranty of ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ; GNU General Public License for more details. ; You should have received a copy of the GNU General Public License ; along with this program. If not, see <http://www.gnu.org/licenses/>. ; provides routines for external EEPROM via I2C ; written by: Matthias Heinrichs, info@heinrichsweikamp.com ; written: 051030 ; last updated: 120421 ; known bugs: ; ToDo: incf_eeprom_address macro ext_ee_temp1 ; Will increase eeprom_address:2 with the 8Bit value "ext_ee_temp1" movlw ext_ee_temp1 call incf_eeprom_address0 endm incf_eeprom_address0: addwf eeprom_address+0,F ; increase address movlw d'0' addwfc eeprom_address+1,F return ;============================================================================= ; Will decrease eeprom_address:2 with the 8Bit value "ext_ee_temp1" decf_eeprom_address macro ext_ee_temp1 movlw ext_ee_temp1 call decf_eeprom_address0 endm decf_eeprom_address0: subwf eeprom_address+0,F ; decrease address: do a 16-8bits substract. movlw d'0' subwfb eeprom_address+1,F return ;============================================================================= write_external_eeprom: ; data in WREG ; increase address eeprom_address+0:eeprom_address+1 after write ; with banking after 7FFF #ifdef TESTING ; When Simulating with MPLabSIM, there is no way to emulate external EEPROM... return #endif rcall I2CWRITE ; writes WREG into EEPROM@eeprom_address movlw d'1' ; increase address addwf eeprom_address+0,F movlw d'0' addwfc eeprom_address+1,F return write_external_eeprom_block: ; Writes a block of 64Byte (one page in external EEPROM without stop condition #ifdef TESTING ; When Simulating with MPLabSIM, there is no way to emulate external EEPROM... return #endif btfsc eeprom_blockwrite ; Blockwrite continue? rcall I2CWRITE_BLOCK2 btfss eeprom_blockwrite ; Blockwrite start? rcall I2CWRITE_BLOCK bsf eeprom_blockwrite ; After the start, do blockwriting for the next 63Bytes! movlw d'0' ; increase address incf eeprom_address+0,F addwfc eeprom_address+1,F return I2CWRITE_BLOCK: movwf ext_ee_temp1 ; Data byte in WREG bsf SSPCON2,SEN ; Start condition rcall WaitMSSP movlw b'10101110' ; Bit0=0: WRITE, Bit0=1: READ, BLOCK2 btfss eeprom_address+1,7 ; Access Block2? movlw b'10100110' ; No, -> Bit0=0: WRITE, Bit0=1: READ, BLOCK1 movwf SSPBUF ; control byte rcall WaitMSSP rcall I2C_WaitforACK movff eeprom_address+1,SSPBUF ; High Address byte rcall WaitMSSP rcall I2C_WaitforACK movff eeprom_address+0,SSPBUF ; Low Address byte rcall WaitMSSP rcall I2C_WaitforACK I2CWRITE_BLOCK2: movff ext_ee_temp1, SSPBUF ; Data Byte rcall WaitMSSP rcall I2C_WaitforACK return get_free_EEPROM_location: ; Searches 0xFD, 0xFD, 0xFE and sets Pointer to 0xFE #ifdef TESTING ; In testing mode, find 0x100 (internal EEPROM) as the first free location... clrf eeprom_address+0 ; Not found in entire EEPROM, set to address 0 movlw 0x1 movwf eeprom_address+1 return #endif clrf ext_ee_temp1 ; low address counter clrf ext_ee_temp2 ; high address counter bcf second_FD ; clear flags bcf first_FD bcf eeprom_switched_b1 get_free_EEPROM_location3: bsf SSPCON2, PEN ; Stop condition rcall WaitMSSP bsf SSPCON2,SEN ; Start condition rcall WaitMSSP movlw b'10101110' ; Bit0=0: WRITE, Bit0=1: READ, BLOCK2 btfss ext_ee_temp2,7 ; Access Block2? movlw b'10100110' ; No, -> Bit0=0: WRITE, Bit0=1: READ, BLOCK1 movwf SSPBUF ; control byte rcall WaitMSSP btfsc SSPCON2,ACKSTAT bra get_free_EEPROM_location3 ; EEPROM NOT acknowledged, retry! movff ext_ee_temp2,SSPBUF ; High Address byte rcall WaitMSSP rcall I2C_WaitforACK movff ext_ee_temp1,SSPBUF ; Low Address byte rcall WaitMSSP rcall I2C_WaitforACK bsf SSPCON2,RSEN ; Start condition rcall WaitMSSP movlw b'10101111' ; Bit0=0: WRITE, Bit0=1: READ, BLOCK2 btfss ext_ee_temp2,7 ; Access Block2? movlw b'10100111' ; No, -> Bit0=0: WRITE, Bit0=1: READ, BLOCK1 movwf SSPBUF ; control byte rcall WaitMSSP rcall I2C_WaitforACK get_free_EEPROM_location2: btfsc eeprom_switched_b1 ; Switched to Block1 already? bra get_free_EEPROM_location2_x ; Yes, skip this check! btfsc ext_ee_temp2,7 ; Access Block1? bsf eeprom_switched_b1 ; Yes, and set the flag so this check is skipped in the rest of this routine btfsc ext_ee_temp2,7 ; Access Block1? bra get_free_EEPROM_location3 ; Yes, initiate new read sequence in block1 get_free_EEPROM_location2_x: bsf SSPCON2, RCEN ; Enable recieve mode rcall WaitMSSP btfsc first_FD bra test_2nd_FD bsf first_FD ; found first 0xFD? movlw 0xFD cpfseq SSPBUF bcf first_FD ; No bra get_free_EEPROM_location2c test_2nd_FD: btfsc second_FD bra test_FE bsf second_FD ; found second 0xFD? movlw 0xFD cpfseq SSPBUF bra get_free_EEPROM_location2b ;No, clear both flags bra get_free_EEPROM_location2c test_FE: movlw 0xFE ; found the final 0xFE? cpfseq SSPBUF bra get_free_EEPROM_location2b ;No, clear both flags movff ext_ee_temp1,eeprom_address+0 ;Yes, copy ext_ee_temp1->eeprom_address+0 and movff ext_ee_temp2,eeprom_address+1 ;ext_ee_temp2->eeprom_address+1 bra get_free_EEPROM_location4 ; Done. get_free_EEPROM_location2b: bcf second_FD ; clear both flags! bcf first_FD get_free_EEPROM_location2c: movlw d'1' ; and increase search address addwf ext_ee_temp1,F movlw d'0' addwfc ext_ee_temp2,F movlw 0xFF cpfseq ext_ee_temp2 ; =0xFFFF bra get_free_EEPROM_location2d ; No cpfseq ext_ee_temp1 ; =0xFFFF bra get_free_EEPROM_location2d ; No bra get_free_EEPROM_location3b ; yes get_free_EEPROM_location2d: bsf SSPCON2, ACKEN ; no, send Ack rcall WaitMSSP bra get_free_EEPROM_location2 ; and continue search get_free_EEPROM_location3b: clrf eeprom_address+0 ; Not found in entire EEPROM, set to address 0 clrf eeprom_address+1 get_free_EEPROM_location4: bsf SSPCON2, PEN ; Stop rcall WaitMSSP bcf second_FD ; clear flags bcf first_FD return ; return I2CREAD: rcall I2CREAD_COMMON bsf SSPCON2, PEN ; Stop rcall WaitMSSP return I2CREAD2: ; same as I2CREAD but with automatic address increase rcall I2CREAD I2CREAD2_2: movlw d'1' addwf eeprom_address+0,F movlw d'0' addwfc eeprom_address+1,F return I2CREAD3: ; block read start with automatic address increase rcall I2CREAD_COMMON ; no Stop condition here bra I2CREAD2_2 I2CREAD4: ; block read with automatic address increase bsf SSPCON2,ACKEN ; Master acknowlegde rcall WaitMSSP bsf SSPCON2, RCEN ; Enable recieve mode rcall WaitMSSP movf SSPBUF,W ; copy read byte into WREG ; no Stop condition here bra I2CREAD2_2 I2CREAD_COMMON: bsf SSPCON2, PEN ; Stop rcall WaitMSSP bsf SSPCON2,SEN ; Start condition rcall WaitMSSP movlw b'10101110' ; Bit0=0: WRITE, Bit0=1: READ, BLOCK2 btfss eeprom_address+1,7 ; Access Block2? movlw b'10100110' ; No, -> Bit0=0: WRITE, Bit0=1: READ, BLOCK1 movwf SSPBUF ; control byte rcall WaitMSSP btfsc SSPCON2,ACKSTAT bra I2CREAD ; EEPROM NOT acknowledged, retry! movff eeprom_address+1,SSPBUF ; High Address byte rcall WaitMSSP rcall I2C_WaitforACK movff eeprom_address+0,SSPBUF ; Low Address byte rcall WaitMSSP rcall I2C_WaitforACK bsf SSPCON2,RSEN ; Start condition rcall WaitMSSP movlw b'10101111' ; Bit0=0: WRITE, Bit0=1: READ, BLOCK2 btfss eeprom_address+1,7 ; Access Block2? movlw b'10100111' ; No, -> Bit0=0: WRITE, Bit0=1: READ, BLOCK1 movwf SSPBUF ; control byte rcall WaitMSSP rcall I2C_WaitforACK bsf SSPCON2, RCEN ; Enable recieve mode rcall WaitMSSP movf SSPBUF,W ; copy read byte into WREG return I2CWRITE: movwf ext_ee_temp1 ; Data byte bsf SSPCON2,SEN ; Start condition rcall WaitMSSP movlw b'10101110' ; Bit0=0: WRITE, Bit0=1: READ, BLOCK2 btfss eeprom_address+1,7 ; Access Block2? movlw b'10100110' ; No, -> Bit0=0: WRITE, Bit0=1: READ, BLOCK1 movwf SSPBUF ; control byte rcall WaitMSSP rcall I2C_WaitforACK movff eeprom_address+1,SSPBUF ; High Address byte rcall WaitMSSP rcall I2C_WaitforACK movff eeprom_address+0,SSPBUF ; Low Address byte rcall WaitMSSP rcall I2C_WaitforACK movff ext_ee_temp1, SSPBUF ; Data Byte rcall WaitMSSP rcall I2C_WaitforACK bsf SSPCON2,PEN ; Stop condition rcall WaitMSSP WAITMS d'5' ; Write delay return I2C_WaitforACK: btfsc SSPCON2,ACKSTAT ; checks for ACK bit from slave rcall I2CFail return I2CFail: ostc_debug 'M' ; Sends debug-information to screen if debugmode active bsf LED_red rcall I2CReset ; I2C Reset bcf PIR1,SSPIF clrf i2c_temp return WaitMSSP: decfsz i2c_temp,F ; check for timeout during I2C action bra WaitMSSP2 bra I2CFail ; timeout occured WaitMSSP2: btfss PIR1,SSPIF bra WaitMSSP clrf i2c_temp bcf PIR1,SSPIF nop return I2CReset: ; Something went wrong (Slave holds SDA low?) clrf SSPCON1 ; wake-up slave and reset entire module ostc_debug 'N' ; Sends debug-information to screen if debugmode active clrf SSPCON2 clrf SSPSTAT bcf TRISC,3 ; SCL OUTPUT bsf TRISC,4 ; SDA Input bcf PORTC,3 movlw d'9' movwf i2c_temp ; clock-out 9 clock cycles manually I2CReset_1: bsf PORTC,3 ; SCL=1 nop nop nop nop btfsc PORTC,4 ; SDA=1? bra I2CReset_2 ; =1, SDA has been released from slave bcf PORTC,3 ; SCL=0 nop nop bcf PORTC,3 nop nop decfsz i2c_temp,F bra I2CReset_1 ; check for nine clock cycles I2CReset_2: bsf TRISC,3 ; SCL Input clrf SSPCON1 ; set I²C Mode WAITMS d'10' ; Reset-Timeout for I2C devices movlw SSPSTAT_VALUE movwf SSPSTAT movlw b'00101000' movwf SSPCON1 movlw b'00000000' movwf SSPCON2 movlw SSPADD_VALUE movwf SSPADD bcf LED_red ostc_debug 'O' ; Sends debug-information to screen if debugmode active return ;I2C_TX: ; movwf i2c_temp2 ; Data byte ; bsf SSPCON2,SEN ; Start condition ; rcall WaitMSSP ; movlw b'10010000' ; Bit0=0: WRITE, Bit0=1: READ ; movwf SSPBUF ; control byte ; rcall WaitMSSP ; rcall I2C_WaitforACK ; movff i2c_temp2, SSPBUF ; Data Byte ; rcall WaitMSSP ; rcall I2C_WaitforACK ; bsf SSPCON2,PEN ; Stop condition ; rcall WaitMSSP ; return ;I2C_RX: ; bcf PIR1,SSPIF ; bsf SSPCON2,SEN ; Start condition ; rcall WaitMSSP ; movlw b'10010001' ; Bit0=0: WRITE, Bit0=1: READ ; movwf SSPBUF ; control byte ; rcall WaitMSSP ; rcall I2C_WaitforACK ; bsf SSPCON2, RCEN ; Enable recieve mode ; rcall WaitMSSP ; movff SSPBUF,i2c_temp2 ; Data Byte ; bsf SSPCON2,ACKEN ; Master acknowlegde ; rcall WaitMSSP ; bsf SSPCON2,PEN ; Stop condition ; rcall WaitMSSP ; return