i2cm_sw.c

   1 /*
   2  *  Copyright Droids Corporation, Microb Technology, Eirbot (2005)
   3  *
   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 2 of the License, or
   7  *  (at your option) any later version.
   8  *
   9  *  This program is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *  GNU General Public License for more details.
  13  *
  14  *  You should have received a copy of the GNU General Public License
  15  *  along with this program; if not, write to the Free Software
  16  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  *
  18  *  Revision : $Id$
  19  *
  20  */
  21
  22
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <stdint.h>
  27 #include <aversive.h>
  28
  29 #include <aversive/wait.h>
  30
  31
  32 #include <util/delay.h>
  33
  34
  35 #include "i2cm_sw.h"
  36
  37
  38
  39
  40 volatile i2cm_state g_i2cm_state = NOT_INIT;
  41 volatile uint8_t g_i2cm_byte;
  42
  43 void (*g_i2cm_event)(i2cm_state state);
  44
  45 /*
  46   Mini Arduino
  47   I2C:
  48   A4 = PC4/SDA
  49   A5 = PC5/SCL
  50 */
  51
  52 #define I2CM_SCL_PORT  PORTD
  53 #define I2CM_SCL_BIT   6
  54
  55 #define  I2CM_SDA_PORT PORTD
  56 #define  I2CM_SDA_BIT  5
  57
  58 #define I2CM_SCL   I2CM_SCL_PORT, I2CM_SCL_BIT
  59 #define I2CM_SDA   I2CM_SDA_PORT, I2CM_SDA_BIT
  60
  61
  62
  63
  64 void i2cm_init(void)
  65 {
  66         /*
  67           - port SCL/SDA is set to 0
  68           - i2c is then driven using DDR 0 (Hi-Z) or 1 (For Low)
  69          */
  70
  71         // SCL high
  72         cbi(DDR(I2CM_SCL_PORT),I2CM_SCL_BIT);
  73         I2C_HIGH(I2CM_SCL_PORT, I2CM_SCL_BIT);
  74
  75         // SDA high
  76         cbi(DDR(I2CM_SDA_PORT),I2CM_SDA_BIT);
  77         I2C_HIGH(I2CM_SDA_PORT, I2CM_SDA_BIT);
  78         I2CM_DELAY();
  79
  80         g_i2cm_state = I2CM_READY;
  81 }
  82
  83
  84 void i2cm_manage(void)
  85 {
  86         if ( (g_i2cm_event  != NULL) && (g_i2cm_state  != I2CM_READY) ) {
  87                 g_i2cm_event( g_i2cm_state );
  88                 // reset notification
  89                 if (g_i2cm_state != I2CM_BUSY)
  90                         g_i2cm_state = I2CM_READY;
  91         }
  92 }
  93
  94 uint8_t i2cm_get_state(void)
  95 {
  96         return g_i2cm_state;
  97 }
  98
  99
 100 uint8_t i2cm_get_received_byte(void)
 101 {
 102         g_i2cm_state = I2CM_READY;
 103         return g_i2cm_byte;
 104 }
 105
 106 void i2cm_register_event(void (*func)(i2cm_state state))
 107 {
 108         uint8_t flags;
 109         IRQ_LOCK(flags);
 110         g_i2cm_event = func;
 111         IRQ_UNLOCK(flags);
 112 }
 113
 114
 115 static uint8_t i2cm_send_byte(uint8_t byte)
 116 {
 117         uint8_t mask;
 118         uint8_t err = 0;
 119
 120
 121         g_i2cm_state = I2CM_BUSY;
 122
 123         // SCL should already be low
 124         //  I2C_LOW(I2CM_SCL_PORT, I2CM_SCL_BIT);
 125         //  I2CM_DELAY();
 126
 127         mask = 0x80;
 128         while (mask) {
 129
 130
 131                 // data out
 132                 if (mask & byte)
 133                         I2C_HIGH(I2CM_SDA_PORT, I2CM_SDA_BIT);
 134                 else
 135                         I2C_LOW(I2CM_SDA_PORT, I2CM_SDA_BIT);
 136                 I2CM_DELAY();
 137                 mask >>=1;
 138
 139                 // clock High
 140                 I2C_HIGH(I2CM_SCL_PORT, I2CM_SCL_BIT);
 141                 I2CM_DELAY();
 142                 while ( bit_is_clear(PIN(I2CM_SCL_PORT), I2CM_SCL_BIT) );// slave handshake
 143
 144                 // clock low
 145                 I2C_LOW(I2CM_SCL_PORT, I2CM_SCL_BIT);
 146
 147         }
 148
 149         /* receive ack */
 150
 151         // release SDA
 152         I2C_HIGH(I2CM_SDA_PORT, I2CM_SDA_BIT);
 153         I2CM_BIT_DELAY();
 154
 155         // clock HIGH
 156         I2C_HIGH(I2CM_SCL_PORT, I2CM_SCL_BIT);
 157         I2CM_DELAY();
 158         while ( bit_is_clear(PIN(I2CM_SCL_PORT), I2CM_SCL_BIT) );// slave handshake
 159
 160         // we should receive ACK
 161         if (bit_is_set(PIN(I2CM_SDA_PORT), I2CM_SDA_BIT))
 162                 err = I2CM_SENT_NO_ACK;
 163
 164         // clock low
 165         I2C_LOW(I2CM_SCL_PORT, I2CM_SCL_BIT);
 166         I2CM_DELAY();
 167
 168         return err;
 169 }
 170
 171
 172 uint8_t i2cm_send_start(uint8_t sla_w)
 173 {
 174         uint8_t err;
 175         uint16_t i;
 176         g_i2cm_state = I2CM_BUSY;
 177
 178         I2C_HIGH(I2CM_SCL_PORT, I2CM_SCL_BIT);
 179         I2C_HIGH(I2CM_SDA_PORT, I2CM_SDA_BIT);
 180
 181         I2CM_DELAY();
 182
 183         /* wait for bus realese */
 184         for (i=0;i<0x8000; i++){
 185                 if( bit_is_set(PIN(I2CM_SCL_PORT), I2CM_SCL_BIT) && \
 186                     bit_is_set(PIN(I2CM_SDA_PORT), I2CM_SDA_BIT) )
 187                         break;
 188         }
 189
 190         //      while ( bit_is_clear(PIN(I2CM_SCL_PORT), I2CM_SCL_BIT) );// slave handshake
 191
 192         // start condition
 193         I2C_LOW(I2CM_SDA_PORT, I2CM_SDA_BIT);
 194         I2CM_DELAY();
 195         I2C_LOW(I2CM_SCL_PORT, I2CM_SCL_BIT);
 196         I2CM_DELAY();
 197
 198         err = i2cm_send_byte(sla_w);
 199         return err;
 200 }
 201
 202
 203
 204 uint8_t i2cm_send_stop(void)
 205 {
 206         g_i2cm_state = I2CM_BUSY;
 207
 208         // data down
 209         I2C_LOW(I2CM_SCL_PORT, I2CM_SCL_BIT);
 210         I2C_LOW(I2CM_SDA_PORT, I2CM_SDA_BIT);
 211         I2CM_DELAY();
 212
 213         // stop condition
 214         I2C_HIGH(I2CM_SCL_PORT, I2CM_SCL_BIT);
 215         I2CM_DELAY();
 216         I2C_HIGH(I2CM_SDA_PORT, I2CM_SDA_BIT);
 217         I2CM_DELAY();
 218
 219         g_i2cm_state = I2CM_SENT_STOP;
 220         return 0;
 221 }
 222
 223
 224 uint8_t i2cm_receive_byte(uint8_t last)
 225 {
 226         uint8_t mask,data;
 227
 228         g_i2cm_state = I2CM_BUSY;
 229
 230         I2C_HIGH(I2CM_SDA_PORT, I2CM_SDA_BIT);
 231
 232
 233         data = 0;
 234         mask = 0x80;
 235         while (mask) {
 236
 237                 // clock High
 238                 I2C_HIGH(I2CM_SCL_PORT, I2CM_SCL_BIT);
 239                 I2CM_DELAY();
 240                 while ( bit_is_clear(PIN(I2CM_SCL_PORT), I2CM_SCL_BIT) );// slave handshake
 241
 242                 if (bit_is_set(PIN(I2CM_SDA_PORT),I2CM_SDA_BIT))
 243                         data |= mask;
 244
 245                 // clock low
 246                 I2C_LOW(I2CM_SCL_PORT, I2CM_SCL_BIT);
 247                 I2CM_DELAY();
 248
 249                 mask >>=1;
 250         }
 251
 252         if (!last){
 253                 /* send ack */
 254                 I2C_LOW(I2CM_SDA_PORT, I2CM_SDA_BIT);
 255                 I2CM_BIT_DELAY();
 256         }
 257
 258         // clock HIGH
 259         I2C_HIGH(I2CM_SCL_PORT, I2CM_SCL_BIT);
 260         I2CM_DELAY();
 261         while ( bit_is_clear(PIN(I2CM_SCL_PORT), I2CM_SCL_BIT) );// slave handshake
 262
 263         // clock low
 264         I2C_LOW(I2CM_SCL_PORT, I2CM_SCL_BIT);
 265         I2CM_DELAY();
 266
 267         if (!last) {
 268                 // release DATA
 269                 I2C_HIGH(I2CM_SDA_PORT, I2CM_SDA_BIT);
 270                 I2CM_BIT_DELAY();
 271         }
 272
 273         g_i2cm_byte  = data;
 274         g_i2cm_state = I2CM_RECEIVED_BYTE;
 275
 276         I2C_HIGH(I2CM_SCL_PORT, I2CM_SCL_BIT);
 277
 278         return 0;
 279 }
 280
 281
 282 uint8_t i2cm_send(uint8_t addr, uint8_t* data, uint8_t len)
 283 {
 284         uint8_t i;
 285         uint8_t err = 0;
 286
 287         err = i2cm_send_start((addr<<1) | 0);
 288         if (err)
 289                 return err;
 290
 291         for (i=0; i<len; i++) {
 292                 err = i2cm_send_byte(data[i]);
 293                 if (err)
 294                         break;
 295         }
 296
 297         i2cm_send_stop();
 298         return err;
 299 }
 300
 301
 302 uint8_t i2c_buf[0x20]; /* XXX */
 303
 304 uint8_t i2cm_recv(uint8_t addr, uint8_t len)
 305 {
 306         uint8_t i;
 307         uint8_t err = 0;
 308
 309         err = i2cm_send_start((addr<<1) | 1);
 310         if (err)
 311                 return err;
 312
 313         I2CM_DELAY();
 314
 315         for (i=0; i<len; i++){
 316                 err =i2cm_receive_byte(i == len-1);
 317                 i2c_buf[i] = g_i2cm_byte;
 318                 if (err)
 319                         break;
 320         }
 321         i2cm_send_stop();
 322         return err;
 323 }
 324
 325
 326 uint8_t i2cm_get_recv_buffer(uint8_t* buf, uint8_t len)
 327 {
 328         uint8_t i;
 329         for (i=0; i<len; i++)
 330                 buf[i] = i2c_buf[i];
 331         return len;
 332 }