LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2014.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2014  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaims all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 #include "../../../Common/Common.h"
  32 #if (ARCH == ARCH_AVR8) && defined(TWCR)
  33
  34 #define  __INCLUDE_FROM_TWI_C
  35 #include "../TWI.h"
  36
  37 uint8_t TWI_StartTransmission(const uint8_t SlaveAddress,
  38                               const uint8_t TimeoutMS)
  39 {
  40         for (;;)
  41         {
  42                 bool     BusCaptured = false;
  43                 uint16_t TimeoutRemaining;
  44
  45                 TWCR = ((1 << TWINT) | (1 << TWSTA) | (1 << TWEN));
  46
  47                 TimeoutRemaining = (TimeoutMS * 100);
  48                 while (TimeoutRemaining && !(BusCaptured))
  49                 {
  50                         if (TWCR & (1 << TWINT))
  51                         {
  52                                 switch (TWSR & TW_STATUS_MASK)
  53                                 {
  54                                         case TW_START:
  55                                         case TW_REP_START:
  56                                                 BusCaptured = true;
  57                                                 break;
  58                                         case TW_MT_ARB_LOST:
  59                                                 TWCR = ((1 << TWINT) | (1 << TWSTA) | (1 << TWEN));
  60                                                 continue;
  61                                         default:
  62                                                 TWCR = (1 << TWEN);
  63                                                 return TWI_ERROR_BusFault;
  64                                 }
  65                         }
  66
  67                         _delay_us(10);
  68                         TimeoutRemaining--;
  69                 }
  70
  71                 if (!(TimeoutRemaining))
  72                 {
  73                         TWCR = (1 << TWEN);
  74                         return TWI_ERROR_BusCaptureTimeout;
  75                 }
  76
  77                 TWDR = SlaveAddress;
  78                 TWCR = ((1 << TWINT) | (1 << TWEN));
  79
  80                 TimeoutRemaining = (TimeoutMS * 100);
  81                 while (TimeoutRemaining)
  82                 {
  83                         if (TWCR & (1 << TWINT))
  84                           break;
  85
  86                         _delay_us(10);
  87                         TimeoutRemaining--;
  88                 }
  89
  90                 if (!(TimeoutRemaining))
  91                   return TWI_ERROR_SlaveResponseTimeout;
  92
  93                 switch (TWSR & TW_STATUS_MASK)
  94                 {
  95                         case TW_MT_SLA_ACK:
  96                         case TW_MR_SLA_ACK:
  97                                 return TWI_ERROR_NoError;
  98                         default:
  99                                 TWCR = ((1 << TWINT) | (1 << TWSTO) | (1 << TWEN));
 100                                 return TWI_ERROR_SlaveNotReady;
 101                 }
 102         }
 103 }
 104
 105 bool TWI_SendByte(const uint8_t Byte)
 106 {
 107         TWDR = Byte;
 108         TWCR = ((1 << TWINT) | (1 << TWEN));
 109         while (!(TWCR & (1 << TWINT)));
 110
 111         return ((TWSR & TW_STATUS_MASK) == TW_MT_DATA_ACK);
 112 }
 113
 114 bool TWI_ReceiveByte(uint8_t* const Byte,
 115                                          const bool LastByte)
 116 {
 117         uint8_t TWCRMask;
 118
 119         if (LastByte)
 120           TWCRMask = ((1 << TWINT) | (1 << TWEN));
 121         else
 122           TWCRMask = ((1 << TWINT) | (1 << TWEN) | (1 << TWEA));
 123
 124         TWCR = TWCRMask;
 125         while (!(TWCR & (1 << TWINT)));
 126         *Byte = TWDR;
 127
 128         uint8_t Status = (TWSR & TW_STATUS_MASK);
 129
 130         return ((LastByte) ? (Status == TW_MR_DATA_NACK) : (Status == TW_MR_DATA_ACK));
 131 }
 132
 133 uint8_t TWI_ReadPacket(const uint8_t SlaveAddress,
 134                        const uint8_t TimeoutMS,
 135                        const uint8_t* InternalAddress,
 136                        uint8_t InternalAddressLen,
 137                        uint8_t* Buffer,
 138                        uint8_t Length)
 139 {
 140         uint8_t ErrorCode;
 141
 142         if ((ErrorCode = TWI_StartTransmission((SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_WRITE,
 143                                                TimeoutMS)) == TWI_ERROR_NoError)
 144         {
 145                 while (InternalAddressLen--)
 146                 {
 147                         if (!(TWI_SendByte(*(InternalAddress++))))
 148                         {
 149                                 ErrorCode = TWI_ERROR_SlaveNAK;
 150                                 break;
 151                         }
 152                 }
 153
 154                 if ((ErrorCode = TWI_StartTransmission((SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_READ,
 155                                                                                            TimeoutMS)) == TWI_ERROR_NoError)
 156                 {
 157                         while (Length--)
 158                         {
 159                                 if (!(TWI_ReceiveByte(Buffer++, (Length == 0))))
 160                                 {
 161                                         ErrorCode = TWI_ERROR_SlaveNAK;
 162                                         break;
 163                                 }
 164                         }
 165
 166                         TWI_StopTransmission();
 167                 }
 168         }
 169
 170         return ErrorCode;
 171 }
 172
 173 uint8_t TWI_WritePacket(const uint8_t SlaveAddress,
 174                         const uint8_t TimeoutMS,
 175                         const uint8_t* InternalAddress,
 176                         uint8_t InternalAddressLen,
 177                         const uint8_t* Buffer,
 178                         uint8_t Length)
 179 {
 180         uint8_t ErrorCode;
 181
 182         if ((ErrorCode = TWI_StartTransmission((SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_WRITE,
 183                                                TimeoutMS)) == TWI_ERROR_NoError)
 184         {
 185                 while (InternalAddressLen--)
 186                 {
 187                         if (!(TWI_SendByte(*(InternalAddress++))))
 188                         {
 189                                 ErrorCode = TWI_ERROR_SlaveNAK;
 190                                 break;
 191                         }
 192                 }
 193
 194                 while (Length--)
 195                 {
 196                         if (!(TWI_SendByte(*(Buffer++))))
 197                         {
 198                                 ErrorCode = TWI_ERROR_SlaveNAK;
 199                                 break;
 200                         }
 201                 }
 202
 203                 TWI_StopTransmission();
 204         }
 205
 206         return ErrorCode;
 207 }
 208
 209 #endif