LUFA/Drivers/Peripheral/XMEGA/TWI_XMEGA.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2013.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2013  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_XMEGA)
  33
  34 #define  __INCLUDE_FROM_TWI_C
  35 #include "../TWI.h"
  36
  37 uint8_t TWI_StartTransmission(TWI_t *twi,
  38                               const uint8_t SlaveAddress,
  39                               const uint8_t TimeoutMS)
  40 {
  41   uint16_t TimeoutRemaining;
  42
  43   twi->MASTER.ADDR = SlaveAddress;
  44
  45   TimeoutRemaining = (TimeoutMS * 100);
  46   while (TimeoutRemaining)
  47   {
  48     if (twi->MASTER.STATUS & (TWI_MASTER_WIF_bm | TWI_MASTER_ARBLOST_bm))
  49     {
  50       // Case 1: Arbitration lost.  Try again. (or error)
  51       twi->MASTER.ADDR = SlaveAddress;
  52     }
  53     else if (twi->MASTER.STATUS & (TWI_MASTER_WIF_bm | TWI_MASTER_RXACK_bm))
  54     {
  55       // Case 2: No response from slave.
  56       return TWI_ERROR_SlaveResponseTimeout;
  57     }
  58     else if (twi->MASTER.STATUS & (TWI_MASTER_WIF_bm))
  59     {
  60       // Case 3: Slave ACK the Write. Ready!
  61       return TWI_ERROR_NoError;
  62     }
  63     else if (twi->MASTER.STATUS & (TWI_MASTER_RIF_bm))
  64     {
  65       // Case 4: Slave ACK the Read. Ready! (a byte will be read)
  66       return TWI_ERROR_NoError;
  67     }
  68     // Still waiting..
  69     _delay_us(10);
  70     TimeoutRemaining--;
  71   }
  72
  73   if (!(TimeoutRemaining)) {
  74     if (twi->MASTER.STATUS & TWI_MASTER_CLKHOLD_bm) {
  75       // Release the bus if we're holding it.
  76       twi->MASTER.CTRLC = TWI_MASTER_CMD_STOP_gc;
  77     }
  78   }
  79   return TWI_ERROR_BusCaptureTimeout;
  80 }
  81
  82 bool TWI_SendByte(TWI_t *twi, const uint8_t Byte)
  83 {
  84   // We assume we're ready to write!
  85   twi->MASTER.DATA = Byte;
  86   while (!(twi->MASTER.STATUS & TWI_MASTER_WIF_bm));
  87   return (twi->MASTER.STATUS & TWI_MASTER_WIF_bm) & !(twi->MASTER.STATUS & TWI_MASTER_RXACK_bm);
  88 }
  89
  90 bool TWI_ReceiveByte(TWI_t *twi, uint8_t* const Byte,
  91                                          const bool LastByte)
  92 {
  93   // If we're here, we should already be reading.  Wait if we haven't read yet.
  94   if (twi->MASTER.STATUS & (TWI_MASTER_BUSERR_bm | TWI_MASTER_ARBLOST_bm)) {
  95     return false;
  96   }
  97   while (!(twi->MASTER.STATUS & TWI_MASTER_RIF_bm));
  98   *Byte = twi->MASTER.DATA;
  99   if (LastByte)
 100     twi->MASTER.CTRLC = TWI_MASTER_ACKACT_bm | TWI_MASTER_CMD_RECVTRANS_gc;
 101   else
 102     twi->MASTER.CTRLC = TWI_MASTER_CMD_RECVTRANS_gc;
 103   return true;
 104 }
 105
 106 uint8_t TWI_ReadPacket(TWI_t *twi,
 107                        const uint8_t SlaveAddress,
 108                        const uint8_t TimeoutMS,
 109                        const uint8_t* InternalAddress,
 110                        uint8_t InternalAddressLen,
 111                        uint8_t* Buffer,
 112                        uint8_t Length)
 113 {
 114         uint8_t ErrorCode;
 115
 116         if ((ErrorCode = TWI_StartTransmission(twi, (SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_WRITE,
 117                                                TimeoutMS)) == TWI_ERROR_NoError)
 118         {
 119                 while (InternalAddressLen--)
 120                 {
 121                         if (!(TWI_SendByte(twi, *(InternalAddress++))))
 122                         {
 123                                 ErrorCode = TWI_ERROR_SlaveNAK;
 124                                 break;
 125                         }
 126                 }
 127
 128                 if ((ErrorCode = TWI_StartTransmission(twi, (SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_READ,
 129                                                                                            TimeoutMS)) == TWI_ERROR_NoError)
 130                 {
 131                         while (Length--)
 132                         {
 133                                 if (!(TWI_ReceiveByte(twi, Buffer++, (Length == 0))))
 134                                 {
 135                                         ErrorCode = TWI_ERROR_SlaveNAK;
 136                                         break;
 137                                 }
 138                         }
 139
 140                         TWI_StopTransmission(twi);
 141                 }
 142         }
 143
 144         return ErrorCode;
 145 }
 146
 147 uint8_t TWI_WritePacket(TWI_t *twi,
 148                         const uint8_t SlaveAddress,
 149                         const uint8_t TimeoutMS,
 150                         const uint8_t* InternalAddress,
 151                         uint8_t InternalAddressLen,
 152                         const uint8_t* Buffer,
 153                         uint8_t Length)
 154 {
 155         uint8_t ErrorCode;
 156
 157         if ((ErrorCode = TWI_StartTransmission(twi, (SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_WRITE,
 158                                                TimeoutMS)) == TWI_ERROR_NoError)
 159         {
 160                 while (InternalAddressLen--)
 161                 {
 162                         if (!(TWI_SendByte(twi, *(InternalAddress++))))
 163                         {
 164                                 ErrorCode = TWI_ERROR_SlaveNAK;
 165                                 break;
 166                         }
 167                 }
 168
 169                 while (Length--)
 170                 {
 171                         if (!(TWI_SendByte(twi, *(Buffer++))))
 172                         {
 173                                 ErrorCode = TWI_ERROR_SlaveNAK;
 174                                 break;
 175                         }
 176                 }
 177
 178                 TWI_StopTransmission(twi);
 179         }
 180
 181         return ErrorCode;
 182 }
 183
 184 #endif