Revision 4319e0bc

View differences:

paintboard/code/Makefile
1
SRC = main.c twi.c motor.c
2
HDR = twi.h motor.h
3

  
4
paint: paint.hex
5
	@
6

  
7
%.hex: %.elf
8
	avr-objcopy -j .text -j .data -O ihex $< $@
9

  
10
paint.elf: $(SRC) $(HDR)
11
	avr-gcc -mmcu=atmega168 -DF_CPU=8000000UL $(SRC) -o paint.elf -Os
12

  
13
download: paint.hex
14
	avrdude -c avrispmkII -p m168 -P usb -B 1 -U flash:w:paint.hex
15

  
16
clean:
17
	rm -f paint.elf paint.hex
paintboard/code/main.c
1
#include "twi.h"
2
#include "motor.h"
3
#include <avr/io.h>
4
#include <avr/interrupt.h>
5

  
6
#define TRACKING_ID 0x43
7
#define SERIAL_NUMBER 0x12
8

  
9
// indicies for paintboard internal data
10
#define PAINT_TRACKING_ID       0 // ro
11
#define PAINT_SERIAL_NUMBER     1 // ro
12
#define PAINT_MOTOR_A           2 // r/w
13
#define PAINT_MOTOR_B           3 // r/w
14
#define PAINT_SERVO_A           4 // r/w
15
#define PAINT_SERVO_B           5 // r/w
16
#define PAINT_12V_1             6 // r/w
17
#define PAINT_12V_2             7 // r/w
18
#define PAINT_12V_3             8 // r/w
19
#define PAINT_12V_4             9 // r/w
20

  
21
#define PAINT_DATA_LEN         10
22

  
23
uint8_t internal_index = 0;
24
uint8_t internal_data[PAINT_DATA_LEN] = {
25
  TRACKING_ID,
26
  SERIAL_NUMBER,
27
  0,
28
  0,
29
  0,
30
  0,
31
  0,
32
  0,
33
  0,
34
  0
35
};
36

  
37
void slave_rx(uint8_t* data, int len)
38
{
39
  uint8_t value;
40
  if (len > 0 && data[0] < PAINT_DATA_LEN)
41
  {
42
    internal_index = data[0];
43
    if (len > 1 && internal_index > 1)
44
    {
45
      value = data[1];
46
      internal_data[internal_index] = value;
47
      switch (internal_index) {
48
        case PAINT_MOTOR_A:
49
          /* ...TODO... */
50
          break;
51
        case PAINT_MOTOR_B:
52
          /* ...TODO... */
53
          break;
54
        case PAINT_SERVO_A:
55
          /* ...TODO... */
56
          break;
57
        case PAINT_SERVO_B:
58
          /* ...TODO... */
59
          break;
60
        case PAINT_12V_1:
61
          /* ...TODO... */
62
          break;
63
        case PAINT_12V_2:
64
          /* ...TODO... */
65
          break;
66
        case PAINT_12V_3:
67
          /* ...TODO... */
68
          break;
69
        case PAINT_12V_4:
70
          /* ...TODO... */
71
          break;
72
      }
73
    }
74
  }
75
}
76

  
77
void slave_tx(void)
78
{
79
  twi_transmit(&internal_data[internal_index], 1);
80
  internal_index++;
81
  if (internal_index >= PAINT_DATA_LEN)
82
    internal_index = 0;
83
}
84

  
85
int main()
86
{
87
  sei();
88
  twi_attachSlaveRxEvent(slave_rx);
89
  twi_attachSlaveTxEvent(slave_tx);
90
  twi_setAddress(TRACKING_ID);
91
  twi_init();
92
  motor_init();
93
  while (1)
94
  {
95
  }
96
  return 0;
97
}
paintboard/code/twi.c
1
/*
2
  twi.c - TWI/I2C library for Wiring & Arduino
3
  Copyright (c) 2006 Nicholas Zambetti.  All right reserved.
4

  
5
  This library is free software; you can redistribute it and/or
6
  modify it under the terms of the GNU Lesser General Public
7
  License as published by the Free Software Foundation; either
8
  version 2.1 of the License, or (at your option) any later version.
9

  
10
  This library is distributed in the hope that it will be useful,
11
  but WITHOUT ANY WARRANTY; without even the implied warranty of
12
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13
  Lesser General Public License for more details.
14

  
15
  You should have received a copy of the GNU Lesser General Public
16
  License along with this library; if not, write to the Free Software
17
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
18
*/
19

  
20
#include <math.h>
21
#include <stdlib.h>
22
#include <inttypes.h>
23
#include <avr/io.h>
24
#include <avr/interrupt.h>
25
#include <compat/twi.h>
26

  
27
#ifndef cbi
28
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
29
#endif
30

  
31
#ifndef sbi
32
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
33
#endif
34

  
35
#include "twi.h"
36

  
37
static volatile uint8_t twi_state;
38
static uint8_t twi_slarw;
39

  
40
static void (*twi_onSlaveTransmit)(void);
41
static void (*twi_onSlaveReceive)(uint8_t*, int);
42

  
43
static uint8_t twi_masterBuffer[TWI_BUFFER_LENGTH];
44
static volatile uint8_t twi_masterBufferIndex;
45
static uint8_t twi_masterBufferLength;
46

  
47
static uint8_t twi_txBuffer[TWI_BUFFER_LENGTH];
48
static volatile uint8_t twi_txBufferIndex;
49
static volatile uint8_t twi_txBufferLength;
50

  
51
static uint8_t twi_rxBuffer[TWI_BUFFER_LENGTH];
52
static volatile uint8_t twi_rxBufferIndex;
53

  
54
static volatile uint8_t twi_error;
55

  
56
/* 
57
 * Function twi_init
58
 * Desc     readys twi pins and sets twi bitrate
59
 * Input    none
60
 * Output   none
61
 */
62
void twi_init(void)
63
{
64
  // initialize state
65
  twi_state = TWI_READY;
66
  
67
  // activate internal pullups for twi.
68
  //digitalWrite(SDA, 1);
69
  //digitalWrite(SCL, 1);
70

  
71
  // initialize twi prescaler and bit rate
72
  cbi(TWSR, TWPS0);
73
  cbi(TWSR, TWPS1);
74
  TWBR = ((F_CPU / TWI_FREQ) - 16) / 2;
75

  
76
  /* twi bit rate formula from atmega128 manual pg 204
77
  SCL Frequency = CPU Clock Frequency / (16 + (2 * TWBR))
78
  note: TWBR should be 10 or higher for master mode
79
  It is 72 for a 16mhz Wiring board with 100kHz TWI */
80

  
81
  // enable twi module, acks, and twi interrupt
82
  TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA);
83
}
84

  
85
/* 
86
 * Function twi_slaveInit
87
 * Desc     sets slave address and enables interrupt
88
 * Input    none
89
 * Output   none
90
 */
91
void twi_setAddress(uint8_t address)
92
{
93
  // set twi slave address (skip over TWGCE bit)
94
  TWAR = address << 1;
95
}
96

  
97
/* 
98
 * Function twi_readFrom
99
 * Desc     attempts to become twi bus master and read a
100
 *          series of bytes from a device on the bus
101
 * Input    address: 7bit i2c device address
102
 *          data: pointer to byte array
103
 *          length: number of bytes to read into array
104
 * Output   number of bytes read
105
 */
106
uint8_t twi_readFrom(uint8_t address, uint8_t* data, uint8_t length)
107
{
108
  uint8_t i;
109

  
110
  // ensure data will fit into buffer
111
  if(TWI_BUFFER_LENGTH < length){
112
    return 0;
113
  }
114

  
115
  // wait until twi is ready, become master receiver
116
  while(TWI_READY != twi_state){
117
    continue;
118
  }
119
  twi_state = TWI_MRX;
120
  // reset error state (0xFF.. no error occured)
121
  twi_error = 0xFF;
122

  
123
  // initialize buffer iteration vars
124
  twi_masterBufferIndex = 0;
125
  twi_masterBufferLength = length-1;  // This is not intuitive, read on...
126
  // On receive, the previously configured ACK/NACK setting is transmitted in
127
  // response to the received byte before the interrupt is signalled. 
128
  // Therefor we must actually set NACK when the _next_ to last byte is
129
  // received, causing that NACK to be sent in response to receiving the last
130
  // expected byte of data.
131

  
132
  // build sla+w, slave device address + w bit
133
  twi_slarw = TW_READ;
134
  twi_slarw |= address << 1;
135

  
136
  // send start condition
137
  TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT) | _BV(TWSTA);
138

  
139
  // wait for read operation to complete
140
  while(TWI_MRX == twi_state){
141
    continue;
142
  }
143

  
144
  if (twi_masterBufferIndex < length)
145
    length = twi_masterBufferIndex;
146

  
147
  // copy twi buffer to data
148
  for(i = 0; i < length; ++i){
149
    data[i] = twi_masterBuffer[i];
150
  }
151
	
152
  return length;
153
}
154

  
155
/* 
156
 * Function twi_writeTo
157
 * Desc     attempts to become twi bus master and write a
158
 *          series of bytes to a device on the bus
159
 * Input    address: 7bit i2c device address
160
 *          data: pointer to byte array
161
 *          length: number of bytes in array
162
 *          wait: boolean indicating to wait for write or not
163
 * Output   0 .. success
164
 *          1 .. length to long for buffer
165
 *          2 .. address send, NACK received
166
 *          3 .. data send, NACK received
167
 *          4 .. other twi error (lost bus arbitration, bus error, ..)
168
 */
169
uint8_t twi_writeTo(uint8_t address, uint8_t* data, uint8_t length, uint8_t wait)
170
{
171
  uint8_t i;
172

  
173
  // ensure data will fit into buffer
174
  if(TWI_BUFFER_LENGTH < length){
175
    return 1;
176
  }
177

  
178
  // wait until twi is ready, become master transmitter
179
  while(TWI_READY != twi_state){
180
    continue;
181
  }
182
  twi_state = TWI_MTX;
183
  // reset error state (0xFF.. no error occured)
184
  twi_error = 0xFF;
185

  
186
  // initialize buffer iteration vars
187
  twi_masterBufferIndex = 0;
188
  twi_masterBufferLength = length;
189
  
190
  // copy data to twi buffer
191
  for(i = 0; i < length; ++i){
192
    twi_masterBuffer[i] = data[i];
193
  }
194
  
195
  // build sla+w, slave device address + w bit
196
  twi_slarw = TW_WRITE;
197
  twi_slarw |= address << 1;
198
  
199
  // send start condition
200
  TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT) | _BV(TWSTA);
201

  
202
  // wait for write operation to complete
203
  while(wait && (TWI_MTX == twi_state)){
204
    continue;
205
  }
206
  
207
  if (twi_error == 0xFF)
208
    return 0;	// success
209
  else if (twi_error == TW_MT_SLA_NACK)
210
    return 2;	// error: address send, nack received
211
  else if (twi_error == TW_MT_DATA_NACK)
212
    return 3;	// error: data send, nack received
213
  else
214
    return 4;	// other twi error
215
}
216

  
217
/* 
218
 * Function twi_transmit
219
 * Desc     fills slave tx buffer with data
220
 *          must be called in slave tx event callback
221
 * Input    data: pointer to byte array
222
 *          length: number of bytes in array
223
 * Output   1 length too long for buffer
224
 *          2 not slave transmitter
225
 *          0 ok
226
 */
227
uint8_t twi_transmit(const uint8_t* data, uint8_t length)
228
{
229
  uint8_t i;
230

  
231
  // ensure data will fit into buffer
232
  if(TWI_BUFFER_LENGTH < length){
233
    return 1;
234
  }
235
  
236
  // ensure we are currently a slave transmitter
237
  if(TWI_STX != twi_state){
238
    return 2;
239
  }
240
  
241
  // set length and copy data into tx buffer
242
  twi_txBufferLength = length;
243
  for(i = 0; i < length; ++i){
244
    twi_txBuffer[i] = data[i];
245
  }
246
  
247
  return 0;
248
}
249

  
250
/* 
251
 * Function twi_attachSlaveRxEvent
252
 * Desc     sets function called before a slave read operation
253
 * Input    function: callback function to use
254
 * Output   none
255
 */
256
void twi_attachSlaveRxEvent( void (*function)(uint8_t*, int) )
257
{
258
  twi_onSlaveReceive = function;
259
}
260

  
261
/* 
262
 * Function twi_attachSlaveTxEvent
263
 * Desc     sets function called before a slave write operation
264
 * Input    function: callback function to use
265
 * Output   none
266
 */
267
void twi_attachSlaveTxEvent( void (*function)(void) )
268
{
269
  twi_onSlaveTransmit = function;
270
}
271

  
272
/* 
273
 * Function twi_reply
274
 * Desc     sends byte or readys receive line
275
 * Input    ack: byte indicating to ack or to nack
276
 * Output   none
277
 */
278
void twi_reply(uint8_t ack)
279
{
280
  // transmit master read ready signal, with or without ack
281
  if(ack){
282
    TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWINT) | _BV(TWEA);
283
  }else{
284
	  TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWINT);
285
  }
286
}
287

  
288
/* 
289
 * Function twi_stop
290
 * Desc     relinquishes bus master status
291
 * Input    none
292
 * Output   none
293
 */
294
void twi_stop(void)
295
{
296
  // send stop condition
297
  TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT) | _BV(TWSTO);
298

  
299
  // wait for stop condition to be exectued on bus
300
  // TWINT is not set after a stop condition!
301
  while(TWCR & _BV(TWSTO)){
302
    continue;
303
  }
304

  
305
  // update twi state
306
  twi_state = TWI_READY;
307
}
308

  
309
/* 
310
 * Function twi_releaseBus
311
 * Desc     releases bus control
312
 * Input    none
313
 * Output   none
314
 */
315
void twi_releaseBus(void)
316
{
317
  // release bus
318
  TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT);
319

  
320
  // update twi state
321
  twi_state = TWI_READY;
322
}
323

  
324
SIGNAL(TWI_vect)
325
{
326
  switch(TW_STATUS){
327
    // All Master
328
    case TW_START:     // sent start condition
329
    case TW_REP_START: // sent repeated start condition
330
      // copy device address and r/w bit to output register and ack
331
      TWDR = twi_slarw;
332
      twi_reply(1);
333
      break;
334

  
335
    // Master Transmitter
336
    case TW_MT_SLA_ACK:  // slave receiver acked address
337
    case TW_MT_DATA_ACK: // slave receiver acked data
338
      // if there is data to send, send it, otherwise stop 
339
      if(twi_masterBufferIndex < twi_masterBufferLength){
340
        // copy data to output register and ack
341
        TWDR = twi_masterBuffer[twi_masterBufferIndex++];
342
        twi_reply(1);
343
      }else{
344
        twi_stop();
345
      }
346
      break;
347
    case TW_MT_SLA_NACK:  // address sent, nack received
348
      twi_error = TW_MT_SLA_NACK;
349
      twi_stop();
350
      break;
351
    case TW_MT_DATA_NACK: // data sent, nack received
352
      twi_error = TW_MT_DATA_NACK;
353
      twi_stop();
354
      break;
355
    case TW_MT_ARB_LOST: // lost bus arbitration
356
      twi_error = TW_MT_ARB_LOST;
357
      twi_releaseBus();
358
      break;
359

  
360
    // Master Receiver
361
    case TW_MR_DATA_ACK: // data received, ack sent
362
      // put byte into buffer
363
      twi_masterBuffer[twi_masterBufferIndex++] = TWDR;
364
    case TW_MR_SLA_ACK:  // address sent, ack received
365
      // ack if more bytes are expected, otherwise nack
366
      if(twi_masterBufferIndex < twi_masterBufferLength){
367
        twi_reply(1);
368
      }else{
369
        twi_reply(0);
370
      }
371
      break;
372
    case TW_MR_DATA_NACK: // data received, nack sent
373
      // put final byte into buffer
374
      twi_masterBuffer[twi_masterBufferIndex++] = TWDR;
375
    case TW_MR_SLA_NACK: // address sent, nack received
376
      twi_stop();
377
      break;
378
    // TW_MR_ARB_LOST handled by TW_MT_ARB_LOST case
379

  
380
    // Slave Receiver
381
    case TW_SR_SLA_ACK:   // addressed, returned ack
382
    case TW_SR_GCALL_ACK: // addressed generally, returned ack
383
    case TW_SR_ARB_LOST_SLA_ACK:   // lost arbitration, returned ack
384
    case TW_SR_ARB_LOST_GCALL_ACK: // lost arbitration, returned ack
385
      // enter slave receiver mode
386
      twi_state = TWI_SRX;
387
      // indicate that rx buffer can be overwritten and ack
388
      twi_rxBufferIndex = 0;
389
      twi_reply(1);
390
      break;
391
    case TW_SR_DATA_ACK:       // data received, returned ack
392
    case TW_SR_GCALL_DATA_ACK: // data received generally, returned ack
393
      // if there is still room in the rx buffer
394
      if(twi_rxBufferIndex < TWI_BUFFER_LENGTH){
395
        // put byte in buffer and ack
396
        twi_rxBuffer[twi_rxBufferIndex++] = TWDR;
397
        twi_reply(1);
398
      }else{
399
        // otherwise nack
400
        twi_reply(0);
401
      }
402
      break;
403
    case TW_SR_STOP: // stop or repeated start condition received
404
      // put a null char after data if there's room
405
      if(twi_rxBufferIndex < TWI_BUFFER_LENGTH){
406
        twi_rxBuffer[twi_rxBufferIndex] = '\0';
407
      }
408
      // sends ack and stops interface for clock stretching
409
      twi_stop();
410
      // callback to user defined callback
411
      twi_onSlaveReceive(twi_rxBuffer, twi_rxBufferIndex);
412
      // since we submit rx buffer to "wire" library, we can reset it
413
      twi_rxBufferIndex = 0;
414
      // ack future responses and leave slave receiver state
415
      twi_releaseBus();
416
      break;
417
    case TW_SR_DATA_NACK:       // data received, returned nack
418
    case TW_SR_GCALL_DATA_NACK: // data received generally, returned nack
419
      // nack back at master
420
      twi_reply(0);
421
      break;
422
    
423
    // Slave Transmitter
424
    case TW_ST_SLA_ACK:          // addressed, returned ack
425
    case TW_ST_ARB_LOST_SLA_ACK: // arbitration lost, returned ack
426
      // enter slave transmitter mode
427
      twi_state = TWI_STX;
428
      // ready the tx buffer index for iteration
429
      twi_txBufferIndex = 0;
430
      // set tx buffer length to be zero, to verify if user changes it
431
      twi_txBufferLength = 0;
432
      // request for txBuffer to be filled and length to be set
433
      // note: user must call twi_transmit(bytes, length) to do this
434
      twi_onSlaveTransmit();
435
      // if they didn't change buffer & length, initialize it
436
      if(0 == twi_txBufferLength){
437
        twi_txBufferLength = 1;
438
        twi_txBuffer[0] = 0x00;
439
      }
440
      // transmit first byte from buffer, fall
441
    case TW_ST_DATA_ACK: // byte sent, ack returned
442
      // copy data to output register
443
      TWDR = twi_txBuffer[twi_txBufferIndex++];
444
      // if there is more to send, ack, otherwise nack
445
      if(twi_txBufferIndex < twi_txBufferLength){
446
        twi_reply(1);
447
      }else{
448
        twi_reply(0);
449
      }
450
      break;
451
    case TW_ST_DATA_NACK: // received nack, we are done 
452
    case TW_ST_LAST_DATA: // received ack, but we are done already!
453
      // ack future responses
454
      twi_reply(1);
455
      // leave slave receiver state
456
      twi_state = TWI_READY;
457
      break;
458

  
459
    // All
460
    case TW_NO_INFO:   // no state information
461
      break;
462
    case TW_BUS_ERROR: // bus error, illegal stop/start
463
      twi_error = TW_BUS_ERROR;
464
      twi_stop();
465
      break;
466
  }
467
}
paintboard/code/twi.h
1
/*
2
  twi.h - TWI/I2C library for Wiring & Arduino
3
  Copyright (c) 2006 Nicholas Zambetti.  All right reserved.
4

  
5
  This library is free software; you can redistribute it and/or
6
  modify it under the terms of the GNU Lesser General Public
7
  License as published by the Free Software Foundation; either
8
  version 2.1 of the License, or (at your option) any later version.
9

  
10
  This library is distributed in the hope that it will be useful,
11
  but WITHOUT ANY WARRANTY; without even the implied warranty of
12
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13
  Lesser General Public License for more details.
14

  
15
  You should have received a copy of the GNU Lesser General Public
16
  License along with this library; if not, write to the Free Software
17
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
18
*/
19

  
20
#ifndef twi_h
21
#define twi_h
22

  
23
  #include <inttypes.h>
24

  
25
  //#define ATMEGA8
26

  
27
  #ifndef TWI_FREQ
28
  #define TWI_FREQ 100000L
29
  #endif
30

  
31
  #ifndef TWI_BUFFER_LENGTH
32
  #define TWI_BUFFER_LENGTH 32
33
  #endif
34

  
35
  #define TWI_READY 0
36
  #define TWI_MRX   1
37
  #define TWI_MTX   2
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  #define TWI_SRX   3
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  #define TWI_STX   4
40
  
41
  void twi_init(void);
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  void twi_setAddress(uint8_t);
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  uint8_t twi_readFrom(uint8_t, uint8_t*, uint8_t);
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  uint8_t twi_writeTo(uint8_t, uint8_t*, uint8_t, uint8_t);
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  uint8_t twi_transmit(const uint8_t*, uint8_t);
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  void twi_attachSlaveRxEvent( void (*)(uint8_t*, int) );
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  void twi_attachSlaveTxEvent( void (*)(void) );
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  void twi_reply(uint8_t);
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  void twi_stop(void);
50
  void twi_releaseBus(void);
51

  
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#endif
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