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annotate code_part1/OSTC_code_asm_part1/i2c_eeprom.asm @ 248:571626276aaa
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| author | heinrichsweikamp |
|---|---|
| date | Tue, 29 Mar 2011 21:29:48 +0200 |
| parents | dee88c962653 |
| children | 7250ca7c8d24 |
| rev | line source |
|---|---|
| 0 | 1 |
| 2 ; OSTC - diving computer code | |
| 3 ; Copyright (C) 2008 HeinrichsWeikamp GbR | |
| 4 ; This program is free software: you can redistribute it and/or modify | |
| 5 ; it under the terms of the GNU General Public License as published by | |
| 6 ; the Free Software Foundation, either version 3 of the License, or | |
| 7 ; (at your option) any later version. | |
| 8 ; This program is distributed in the hope that it will be useful, | |
| 9 ; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 10 ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 11 ; GNU General Public License for more details. | |
| 12 ; You should have received a copy of the GNU General Public License | |
| 13 ; along with this program. If not, see <http://www.gnu.org/licenses/>. | |
| 14 ; provides routines for external EEPROM via I2C | |
| 15 ; written by: Matthias Heinrichs, info@heinrichsweikamp.com | |
| 16 ; written: 10/30/05 | |
| 17 ; last updated: 08/21/06 | |
| 18 ; known bugs: | |
| 19 ; ToDo: use 2nd 32KB from external EEPROM for something | |
| 20 | |
| 21 incf_eeprom_address macro ext_ee_temp1 ; Will increase eeprom_address:2 with the 8Bit value "ext_ee_temp1" and takes | |
| 148 | 22 movlw ext_ee_temp1 ; care of bank switching at 0x8000 |
| 23 call incf_eeprom_address0 | |
| 0 | 24 endm |
| 25 | |
| 26 incf_eeprom_address0: | |
| 148 | 27 addwf eeprom_address+0,F ; increase address |
| 28 movlw d'0' | |
| 29 addwfc eeprom_address+1,F | |
| 0 | 30 |
| 148 | 31 btfss eeprom_address+1,7 ; at address 8000? |
| 32 return ; No, continue | |
| 33 | |
| 34 ; Yes, clear eeprom_address:2 | |
| 35 clrf eeprom_address+0 ; Clear eeprom address | |
| 36 clrf eeprom_address+1 | |
| 37 return ; Done. | |
| 38 | |
| 39 ;============================================================================= | |
| 40 ; Will decrease eeprom_address:2 with the 8Bit value "ext_ee_temp1" and takes | |
| 41 ; care of bank switching at 0x8000 | |
| 42 | |
| 43 decf_eeprom_address macro ext_ee_temp1 | |
| 44 movlw ext_ee_temp1 | |
| 45 call decf_eeprom_address0 | |
| 46 endm | |
| 0 | 47 |
| 48 decf_eeprom_address0: | |
| 148 | 49 subwf eeprom_address+0,F ; decrease address: do a 16-8bits substract. |
| 50 movlw d'0' | |
| 51 subwfb eeprom_address+1,F | |
| 0 | 52 |
| 148 | 53 btfss eeprom_address+1,7 ; at address 8000? |
| 54 return ; No, done. | |
| 0 | 55 |
| 148 | 56 movlw b'01111111' ; yes, reset highbyte |
| 57 movwf eeprom_address+1 | |
| 58 return ; Done. | |
| 59 | |
| 60 ;============================================================================= | |
| 0 | 61 |
| 62 write_external_eeprom: ; data in WREG | |
| 63 ; increase address eeprom_address+0:eeprom_address+1 after write | |
| 64 ; with banking after 7FFF | |
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65 #ifdef TESTING |
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66 ; When Simulating with MPLabSIM, there is no way to emulate external EEPROM... |
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67 return |
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68 #endif |
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69 |
| 0 | 70 rcall I2CWRITE ; writes WREG into EEPROM@eeprom_address |
| 71 movlw d'1' ; increase address | |
| 72 addwf eeprom_address+0,F | |
| 73 movlw d'0' | |
| 74 addwfc eeprom_address+1,F | |
| 75 bcf eeprom_overflow | |
| 76 btfss eeprom_address+1,7 ; at address 8000? | |
| 77 return ; no, return | |
| 78 | |
| 79 clrf eeprom_address+0 ; Clear eeprom address | |
| 80 clrf eeprom_address+1 | |
| 81 bsf eeprom_overflow ; and set overflow bit | |
| 82 return | |
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83 |
| 0 | 84 write_external_eeprom_block: ; Writes a block of 64Byte (one page in external EEPROM without stop condition |
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85 #ifdef TESTING |
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86 ; When Simulating with MPLabSIM, there is no way to emulate external EEPROM... |
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87 return |
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88 #endif |
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89 |
| 0 | 90 btfsc eeprom_blockwrite ; Blockwrite continue? |
| 91 rcall I2CWRITE_BLOCK2 | |
| 92 btfss eeprom_blockwrite ; Blockwrite start? | |
| 93 rcall I2CWRITE_BLOCK | |
| 94 bsf eeprom_blockwrite ; After the start, do blockwriting for the next 63Bytes! | |
| 95 | |
| 96 movlw d'0' ; increase address | |
| 97 incf eeprom_address+0,F | |
| 98 addwfc eeprom_address+1,F | |
| 99 bcf eeprom_overflow | |
| 100 | |
| 101 btfss eeprom_address+1,7 ; at address 8000 | |
| 102 return ; no, return | |
| 103 | |
| 104 clrf eeprom_address+0 ; Clear eeprom address | |
| 105 clrf eeprom_address+1 | |
| 106 bsf eeprom_overflow ; and set overflow bit | |
| 107 return | |
| 108 I2CWRITE_BLOCK: | |
| 109 movwf ext_ee_temp1 ; Data byte in WREG | |
| 110 bsf SSPCON2,SEN ; Start condition | |
| 111 rcall WaitMSSP | |
| 112 movlw b'10100110' ; Bit0=0: WRITE, Bit0=1: READ | |
| 113 movwf SSPBUF ; control byte | |
| 114 rcall WaitMSSP | |
| 115 rcall I2C_WaitforACK | |
| 116 movff eeprom_address+1,SSPBUF ; High Address byte | |
| 117 rcall WaitMSSP | |
| 118 rcall I2C_WaitforACK | |
| 119 movff eeprom_address+0,SSPBUF ; Low Address byte | |
| 120 rcall WaitMSSP | |
| 121 rcall I2C_WaitforACK | |
| 122 I2CWRITE_BLOCK2: | |
| 123 movff ext_ee_temp1, SSPBUF ; Data Byte | |
| 124 rcall WaitMSSP | |
| 125 rcall I2C_WaitforACK | |
| 126 return | |
| 127 | |
| 128 | |
| 129 get_free_EEPROM_location: ; Searches 0xFD, 0xFD, 0xFE and sets Pointer to 0xFE | |
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130 |
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131 #ifdef TESTING |
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132 ; In testing mode, find 0x100 (internal EEPROM) as the first free location... |
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133 clrf eeprom_address+0 ; Not found in entire EEPROM, set to address 0 |
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134 movlw 0x1 |
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135 movwf eeprom_address+1 |
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136 return |
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137 #endif |
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138 |
| 0 | 139 clrf ext_ee_temp1 ; low address counter |
| 140 clrf ext_ee_temp2 ; high address counter | |
| 141 bcf second_FD ; clear flags | |
| 142 bcf first_FD | |
| 143 get_free_EEPROM_location3: | |
| 144 bsf SSPCON2, PEN ; Stop condition | |
| 145 rcall WaitMSSP | |
| 146 bsf SSPCON2,SEN ; Start condition | |
| 147 rcall WaitMSSP | |
| 148 movlw b'10100110' ; Bit0=0: WRITE, Bit0=1: READ | |
| 149 movwf SSPBUF ; control byte | |
| 150 rcall WaitMSSP | |
| 151 btfsc SSPCON2,ACKSTAT | |
| 152 bra get_free_EEPROM_location3 ; EEPROM NOT acknowledged, retry! | |
| 153 | |
| 154 movff ext_ee_temp2,SSPBUF ; High Address byte | |
| 155 rcall WaitMSSP | |
| 156 rcall I2C_WaitforACK | |
| 157 movff ext_ee_temp1,SSPBUF ; Low Address byte | |
| 158 rcall WaitMSSP | |
| 159 rcall I2C_WaitforACK | |
| 160 | |
| 161 bsf SSPCON2,RSEN ; Start condition | |
| 162 rcall WaitMSSP | |
| 163 movlw b'10100111' ; Bit0=0: WRITE, Bit0=1: READ | |
| 164 movwf SSPBUF ; control byte | |
| 165 rcall WaitMSSP | |
| 166 rcall I2C_WaitforACK | |
| 167 | |
| 168 get_free_EEPROM_location2: | |
| 169 bsf SSPCON2, RCEN ; Enable recieve mode | |
| 170 rcall WaitMSSP | |
| 171 btfsc first_FD | |
| 172 bra test_2nd_FD | |
| 173 bsf first_FD ; found first 0xFD? | |
| 174 movlw 0xFD | |
| 175 cpfseq SSPBUF | |
| 176 bcf first_FD ; No | |
| 177 bra get_free_EEPROM_location2c | |
| 178 | |
| 179 test_2nd_FD: | |
| 180 btfsc second_FD | |
| 181 bra test_FE | |
| 182 bsf second_FD ; found second 0xFD? | |
| 183 movlw 0xFD | |
| 184 cpfseq SSPBUF | |
| 185 bra get_free_EEPROM_location2b ;No, clear both flags | |
| 186 bra get_free_EEPROM_location2c | |
| 187 test_FE: | |
| 188 movlw 0xFE ; found the final 0xFE? | |
| 189 cpfseq SSPBUF | |
| 190 bra get_free_EEPROM_location2b ;No, clear both flags | |
| 191 movff ext_ee_temp1,eeprom_address+0 ;Yes, copy ext_ee_temp1->eeprom_address+0 and | |
| 192 movff ext_ee_temp2,eeprom_address+1 ;ext_ee_temp2->eeprom_address+1 | |
| 193 bra get_free_EEPROM_location4 ; Done. | |
| 194 | |
| 195 get_free_EEPROM_location2b: | |
| 196 bcf second_FD ; clear both flags! | |
| 197 bcf first_FD | |
| 198 get_free_EEPROM_location2c: | |
| 199 movlw d'1' ; and increase search address | |
| 200 addwf ext_ee_temp1,F | |
| 201 movlw d'0' | |
| 202 addwfc ext_ee_temp2,F | |
| 203 | |
| 42 | 204 btfsc ext_ee_temp2,7 ; 0x8000 reached? |
| 0 | 205 bra get_free_EEPROM_location3b ; yes |
| 206 | |
| 207 bsf SSPCON2, ACKEN ; no, send Ack | |
| 208 rcall WaitMSSP | |
| 209 bra get_free_EEPROM_location2 ; and continue search | |
| 210 get_free_EEPROM_location3b: | |
| 211 clrf eeprom_address+0 ; Not found in entire EEPROM, set to address 0 | |
| 212 clrf eeprom_address+1 | |
| 213 get_free_EEPROM_location4: | |
| 214 bsf SSPCON2, PEN ; Stop | |
| 215 rcall WaitMSSP | |
| 216 | |
| 217 bcf second_FD ; clear flags | |
| 218 bcf first_FD | |
| 219 return ; return | |
| 220 | |
| 221 | |
| 222 I2CREAD: | |
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223 rcall I2CREAD_COMMON |
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224 bsf SSPCON2, PEN ; Stop |
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225 rcall WaitMSSP |
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226 return |
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227 |
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228 I2CREAD2: ; same as I2CREAD but with automatic address increase |
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229 rcall I2CREAD |
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230 I2CREAD2_2: |
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231 movlw d'1' |
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232 addwf eeprom_address+0,F |
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233 movlw d'0' |
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234 addwfc eeprom_address+1,F |
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235 bcf eeprom_overflow |
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236 btfss eeprom_address+1,7 ; at 0x8000? |
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237 return ; no, return |
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238 |
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239 clrf eeprom_address+0 ; Yes, clear address |
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240 clrf eeprom_address+1 |
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241 bsf eeprom_overflow ; and set overflow bit |
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242 return |
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243 |
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244 I2CREAD3: ; block read start with automatic address increase |
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245 rcall I2CREAD_COMMON |
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246 ; no Stop condition here |
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247 bra I2CREAD2_2 |
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248 |
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249 I2CREAD4: ; block read with automatic address increase |
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250 bsf SSPCON2,ACKEN ; Master acknowlegde |
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251 rcall WaitMSSP |
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252 bsf SSPCON2, RCEN ; Enable recieve mode |
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253 rcall WaitMSSP |
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254 movf SSPBUF,W ; copy read byte into WREG |
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255 ; no Stop condition here |
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256 bra I2CREAD2_2 |
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257 |
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258 |
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259 I2CREAD_COMMON: |
| 0 | 260 bsf SSPCON2, PEN ; Stop |
| 261 rcall WaitMSSP | |
| 262 bsf SSPCON2,SEN ; Start condition | |
| 263 rcall WaitMSSP | |
| 264 movlw b'10100110' ; Bit0=0: WRITE, Bit0=1: READ | |
| 265 movwf SSPBUF ; control byte | |
| 266 rcall WaitMSSP | |
| 267 btfsc SSPCON2,ACKSTAT | |
| 268 bra I2CREAD ; EEPROM NOT acknowledged, retry! | |
| 269 movff eeprom_address+1,SSPBUF ; High Address byte | |
| 270 rcall WaitMSSP | |
| 271 rcall I2C_WaitforACK | |
| 272 movff eeprom_address+0,SSPBUF ; Low Address byte | |
| 273 rcall WaitMSSP | |
| 274 rcall I2C_WaitforACK | |
| 275 | |
| 276 bsf SSPCON2,RSEN ; Start condition | |
| 277 rcall WaitMSSP | |
| 278 movlw b'10100111' ; Bit0=0: WRITE, Bit0=1: READ | |
| 279 movwf SSPBUF ; control byte | |
| 280 rcall WaitMSSP | |
| 281 rcall I2C_WaitforACK | |
| 282 | |
| 283 bsf SSPCON2, RCEN ; Enable recieve mode | |
| 284 rcall WaitMSSP | |
| 285 movf SSPBUF,W ; copy read byte into WREG | |
| 286 return | |
| 287 | |
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288 |
| 0 | 289 I2CWRITE: |
| 290 movwf ext_ee_temp1 ; Data byte | |
| 291 bsf SSPCON2,SEN ; Start condition | |
| 292 rcall WaitMSSP | |
| 293 movlw b'10100110' ; Bit0=0: WRITE, Bit0=1: READ | |
| 294 movwf SSPBUF ; control byte | |
| 295 rcall WaitMSSP | |
| 296 rcall I2C_WaitforACK | |
| 297 movff eeprom_address+1,SSPBUF ; High Address byte | |
| 298 rcall WaitMSSP | |
| 299 rcall I2C_WaitforACK | |
| 300 movff eeprom_address+0,SSPBUF ; Low Address byte | |
| 301 rcall WaitMSSP | |
| 302 rcall I2C_WaitforACK | |
| 303 movff ext_ee_temp1, SSPBUF ; Data Byte | |
| 304 rcall WaitMSSP | |
| 305 rcall I2C_WaitforACK | |
| 306 bsf SSPCON2,PEN ; Stop condition | |
| 307 rcall WaitMSSP | |
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308 WAITMS d'5' ; Write delay |
| 0 | 309 return |
| 310 | |
| 311 I2C_WaitforACK: | |
| 312 btfsc SSPCON2,ACKSTAT ; checks for ACK bit from slave | |
| 313 rcall I2CFail | |
| 314 return | |
| 315 | |
| 316 I2CFail: | |
| 317 ostc_debug 'M' ; Sends debug-information to screen if debugmode active | |
| 21 | 318 bsf LED_red |
| 0 | 319 rcall I2CReset ; I2C Reset |
| 320 bcf PIR1,SSPIF | |
| 321 clrf i2c_temp | |
| 322 return | |
| 323 | |
| 324 WaitMSSP: | |
| 325 decfsz i2c_temp,F ; check for timeout during I2C action | |
| 326 bra WaitMSSP2 | |
| 327 bra I2CFail ; timeout occured | |
| 328 WaitMSSP2: | |
| 329 btfss PIR1,SSPIF | |
| 330 bra WaitMSSP | |
| 331 clrf i2c_temp | |
| 332 bcf PIR1,SSPIF | |
| 333 return | |
| 334 | |
| 335 I2CReset: ; Something went wrong (Slave holds SDA low?) | |
| 336 clrf SSPCON1 ; wake-up slave and reset entire module | |
| 337 ostc_debug 'N' ; Sends debug-information to screen if debugmode active | |
| 338 clrf SSPCON2 | |
| 339 clrf SSPSTAT | |
| 340 bcf TRISC,3 ; SCL OUTPUT | |
| 341 bsf TRISC,4 ; SDA Input | |
| 342 bcf PORTC,3 | |
| 343 movlw d'9' | |
| 344 movwf i2c_temp ; clock-out 9 clock cycles manually | |
| 345 I2CReset_1: | |
| 346 bsf PORTC,3 ; SCL=1 | |
| 347 nop | |
| 348 btfsc PORTC,4 ; SDA=1? | |
| 349 bra I2CReset_2 ; =1, SDA has been released from slave | |
| 350 bcf PORTC,3 ; SCL=0 | |
| 351 bcf PORTC,3 | |
| 352 decfsz i2c_temp,F | |
| 353 bra I2CReset_1 ; check for nine clock cycles | |
| 354 I2CReset_2: | |
| 355 bsf TRISC,3 ; SCL Input | |
| 356 clrf SSPCON1 ; set I²C Mode | |
| 357 WAITMS d'10' ; Reset-Timeout for I2C devices | |
| 358 movlw b'00000000' | |
| 359 movwf SSPSTAT | |
| 360 movlw b'00101000' | |
| 361 movwf SSPCON1 | |
| 362 movlw b'00000000' | |
| 363 movwf SSPCON2 | |
| 364 movlw d'8' ; 400kHz I2C clock @ 16MHz Fcy | |
| 365 movwf SSPADD | |
| 21 | 366 bcf LED_red |
| 0 | 367 ostc_debug 'O' ; Sends debug-information to screen if debugmode active |
| 368 return | |
| 53 | 369 |
| 370 ;I2C_TX: | |
| 371 ; movwf i2c_temp2 ; Data byte | |
| 372 ; bsf SSPCON2,SEN ; Start condition | |
| 373 ; rcall WaitMSSP | |
| 374 ; movlw b'10010000' ; Bit0=0: WRITE, Bit0=1: READ | |
| 375 ; movwf SSPBUF ; control byte | |
| 376 ; rcall WaitMSSP | |
| 377 ; rcall I2C_WaitforACK | |
| 378 ; movff i2c_temp2, SSPBUF ; Data Byte | |
| 379 ; rcall WaitMSSP | |
| 380 ; rcall I2C_WaitforACK | |
| 381 ; bsf SSPCON2,PEN ; Stop condition | |
| 382 ; rcall WaitMSSP | |
| 383 ; return | |
| 384 ;I2C_RX: | |
| 385 ; bcf PIR1,SSPIF | |
| 386 ; bsf SSPCON2,SEN ; Start condition | |
| 387 ; rcall WaitMSSP | |
| 388 ; movlw b'10010001' ; Bit0=0: WRITE, Bit0=1: READ | |
| 389 ; movwf SSPBUF ; control byte | |
| 390 ; rcall WaitMSSP | |
| 391 ; rcall I2C_WaitforACK | |
| 392 ; bsf SSPCON2, RCEN ; Enable recieve mode | |
| 393 ; rcall WaitMSSP | |
| 394 ; movff SSPBUF,i2c_temp2 ; Data Byte | |
| 395 ; bsf SSPCON2,ACKEN ; Master acknowlegde | |
| 396 ; rcall WaitMSSP | |
| 397 ; bsf SSPCON2,PEN ; Stop condition | |
| 398 ; rcall WaitMSSP | |
| 399 ; return |