src/commsISRs.c

   1 /* FreeEMS - the open source engine management system
   2  *
   3  * Copyright 2008-2012 Fred Cooke
   4  *
   5  * This file is part of the FreeEMS project.
   6  *
   7  * FreeEMS software is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation, either version 3 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * FreeEMS software is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with any FreeEMS software.  If not, see http://www.gnu.org/licenses/
  19  *
  20  * We ask that if you make any changes to this file you email them upstream to
  21  * us at admin(at)diyefi(dot)org or, even better, fork the code on github.com!
  22  *
  23  * Thank you for choosing FreeEMS to run your engine!
  24  */
  25
  26
  27 /** @file
  28  *
  29  * @ingroup interruptHandlers
  30  * @ingroup communicationsFiles
  31  *
  32  * @brief Send and receive bytes serially
  33  *
  34  * This file contains the code for both send and receive of serial bytes
  35  * through the UART SCI0 device. It is purely interrupt driven and controlled
  36  * by a set of register and non-register flags that are toggled both inside
  37  * and outside this file. Some additional helper functions are also kept here.
  38  *
  39  * @todo TODO SCI0ISR() needs to be split into some hash defines and an include file that formats it to be the ISR for a specific channel.
  40  */
  41
  42
  43 #define COMMSISRS_C
  44 #include "inc/freeEMS.h"
  45 #include "inc/interrupts.h"
  46 #include "inc/utils.h"
  47 #include "inc/commsCore.h"
  48 #include "inc/commsISRs.h"
  49
  50
  51 /* The C89 standard is used in the 3.3.6 GCC compiler, please *
  52  * see the following URL for more info on inline functions :  *
  53  * http://gcc.gnu.org/onlinedocs/gcc-3.3.6/Inline.html#Inline */
  54
  55
  56 /** @brief Reset Receive State
  57  *
  58  * Reset communications reception to the state provided.
  59  *
  60  * @todo TODO this is in the wrong file!! Either move the header declaration or move the function!
  61  *
  62  * @param sourceIDState is the state to apply to the RX buffer state variable.
  63  */
  64 void resetReceiveState(unsigned char sourceIDState){
  65         /* Set the receive buffer pointer to the beginning */
  66         RXBufferCurrentPosition = (unsigned char*)&RXBuffer;
  67
  68         /* Zero the flags */
  69         RXStateFlags = 0;
  70
  71         /* Set the source ID state (clear all or all but one flag(s)) */
  72         RXBufferContentSourceID = sourceIDState;
  73
  74         /* Which ever interface we are setting is the one we came from. By definition */
  75         /* it must be on and we want it to stay on, so just turn off all the others.  */
  76         if(sourceIDState & COM_SET_SCI0_INTERFACE_ID){
  77                 /* Turn off all others here */
  78                 /// @todo TODO CAN0CTL1 &= CANCTL1_RX_DISABLE;
  79                 /// @todo TODO CAN0CTL1 &= CANCTL1_RX_ISR_DISABLE;
  80                 /* SPI ? I2C ? SCI1 ? */
  81         }else if(sourceIDState & COM_SET_CAN0_INTERFACE_ID){
  82                 /* Turn off all others here */
  83                 /* Only SCI for now */
  84                 SCI0CR2 &= SCICR2_RX_ISR_DISABLE;
  85                 /* SPI ? I2C ? SCI1 ? */
  86         }else{ /* If clearing all flags then enable RX on all interfaces */
  87                 /* Only SCI for now */
  88                 unsigned char devnull; // Is there a better way to do this?
  89                 devnull = SCI0SR1; // Reading the flags combined with...
  90                 devnull = SCI0DRL; // ...reading the data clears the flags
  91                 SCI0CR2 |= SCICR2_RX_ISR_ENABLE;
  92                 /// @todo TODO CAN0CTL1 |= CANCTL1_RX_ENABLE;
  93                 /// @todo TODO CAN0CTL1 |= CANCTL1_RX_ISR_ENABLE;
  94                 /* SPI ? I2C ? SCI1 ? */
  95         }
  96 }
  97
  98
  99 /** @brief Serial Communication Interface 0 ISR
 100  *
 101  * SCI0 ISR handles all interrupts for SCI0 by reading flags and acting
 102  * appropriately. Its functions are to send raw bytes out over the wire from a
 103  * buffer and to receive bytes from the wire un-escape them, checksum them and
 104  * store them in a buffer.
 105  *
 106  * @todo TODO Move this code into an include file much like the fuel interrupts such that it can be used for multiple UART SCI devices without duplication.
 107  * @todo TODO Fix the init code such that this doesn't run at boot without a serail device attached. Clear buffer maybe? or flag clearing/isr enabling ordering?
 108  */
 109 void SCI0ISR(){
 110         // OK before flag reading because cleared when SCI0DRL accessed (R or W)
 111         DEBUG_TURN_PIN_ON(DECODER_BENCHMARKS, BIT4, PORTB);
 112
 113         /* Read the flags register */
 114         unsigned char flags = SCI0SR1;
 115         /* Note: Combined with reading or writing the data register this also clears the flags. */
 116
 117         /* If either of these flags is set, we need to read the data to clear the flag */
 118         if(flags & (SCISR1_RX_REGISTER_FULL | SCISR1_RX_OVERRUN)){
 119                 /* Grab the received byte from the register to clear the flag, whether we want the data or not */
 120                 unsigned char rawByte = SCI0DRL;
 121
 122                 /* If the RX interrupt is enabled do something useful */
 123                 if(SCI0CR2 & SCICR2_RX_ISR_ENABLE){
 124                         if(flags & (SCISR1_RX_NOISE | SCISR1_RX_FRAMING | SCISR1_RX_PARITY | SCISR1_RX_OVERRUN)){
 125                                 /* If there is noise on the receive line record it */
 126                                 if(flags & SCISR1_RX_NOISE){
 127                                         FLAG_AND_INC_FLAGGABLE(FLAG_SERIAL_NOISE_ERRORS_OFFSET);
 128                                         KeyUserDebugs.serialHardwareErrors++;
 129                                 }
 130
 131                                 /* If a framing error occurs record it */
 132                                 if(flags & SCISR1_RX_FRAMING){
 133                                         FLAG_AND_INC_FLAGGABLE(FLAG_SERIAL_FRAMING_ERRORS_OFFSET);
 134                                         KeyUserDebugs.serialHardwareErrors++;
 135                                 }
 136
 137                                 /* If a parity error occurs record it */
 138                                 if(flags & SCISR1_RX_PARITY){
 139                                         FLAG_AND_INC_FLAGGABLE(FLAG_SERIAL_PARITY_ERRORS_OFFSET);
 140                                         KeyUserDebugs.serialHardwareErrors++;
 141                                 }
 142
 143                                 /* If an overrun occurs record it */
 144                                 if(flags & SCISR1_RX_OVERRUN){
 145                                         FLAG_AND_INC_FLAGGABLE(FLAG_SERIAL_OVERRUN_ERRORS_OFFSET);
 146                                         KeyUserDebugs.serialOverrunErrors++;
 147                                 }
 148
 149                                 resetReceiveState(CLEAR_ALL_SOURCE_ID_FLAGS);
 150                         }else{ // Process the received data
 151                                 /* Look for a start byte to indicate a new packet */
 152                                 if(rawByte == START_BYTE){
 153                                         /* If another interface is using it (Note, clear flag, not normal) */
 154                                         if(RXBufferContentSourceID & COM_CLEAR_SCI0_INTERFACE_ID){
 155                                                 /* Turn off our reception */
 156                                                 SCI0CR2 &= SCICR2_RX_ISR_DISABLE;
 157                                         }else{
 158                                                 /* If we are using it */
 159                                                 if(RXBufferContentSourceID & COM_SET_SCI0_INTERFACE_ID){
 160                                                         /* Increment the counter */
 161                                                         FLAG_AND_INC_FLAGGABLE(FLAG_SERIAL_STARTS_INSIDE_A_PACKET_OFFSET);
 162                                                         KeyUserDebugs.serialAndCommsCodeErrors++;
 163                                                 }
 164                                                 /* Reset to us using it unless someone else was */
 165                                                 resetReceiveState(COM_SET_SCI0_INTERFACE_ID);
 166                                         }
 167                                 }else if((unsigned short)RXBufferCurrentPosition >= ((unsigned short)&RXBuffer + RX_BUFFER_SIZE)){
 168                                         /* Buffer was full, record and reset */
 169                                         FLAG_AND_INC_FLAGGABLE(FLAG_SERIAL_PACKETS_OVER_LENGTH_OFFSET);
 170                                         KeyUserDebugs.serialAndCommsCodeErrors++;
 171                                         resetReceiveState(CLEAR_ALL_SOURCE_ID_FLAGS);
 172                                 }else if(RXBufferContentSourceID & COM_SET_SCI0_INTERFACE_ID){
 173                                         if(RXStateFlags & RX_SCI_ESCAPED_NEXT){
 174                                                 /* Clear escaped byte next flag, thanks Karsten! ((~ != !) == (! ~= ~)) == LOL */
 175                                                 RXStateFlags &= RX_SCI_NOT_ESCAPED_NEXT;
 176
 177                                                 if(rawByte == ESCAPED_ESCAPE_BYTE){
 178                                                         *RXBufferCurrentPosition++ = ESCAPE_BYTE;
 179                                                 }else if(rawByte == ESCAPED_START_BYTE){
 180                                                         *RXBufferCurrentPosition++ = START_BYTE;
 181                                                 }else if(rawByte == ESCAPED_STOP_BYTE){
 182                                                         *RXBufferCurrentPosition++ = STOP_BYTE;
 183                                                 }else{
 184                                                         /* Otherwise reset and record as data is bad */
 185                                                         resetReceiveState(CLEAR_ALL_SOURCE_ID_FLAGS);
 186                                                         FLAG_AND_INC_FLAGGABLE(FLAG_SERIAL_ESCAPE_PAIR_MISMATCHES_OFFSET);
 187                                                         KeyUserDebugs.serialAndCommsCodeErrors++;
 188                                                 }
 189                                         }else if(rawByte == ESCAPE_BYTE){
 190                                                 /* Drop the escape and set the flag to indicate that the next byte should be un-escaped. */
 191                                                 RXStateFlags |= RX_SCI_ESCAPED_NEXT;
 192                                         }else if(rawByte == STOP_BYTE){
 193                                                 /* Turn off reception */
 194                                                 SCI0CR2 &= SCICR2_RX_ISR_DISABLE;
 195                                                 RXStateFlags |= RX_READY_TO_PROCESS;
 196                                         }else{
 197                                                 *RXBufferCurrentPosition++ = rawByte;
 198                                         }
 199                                 } /* ELSE: Do nothing : drop the byte */
 200                         }
 201                 }
 202         }
 203
 204         /* If the TX interrupt is enabled check the register empty flag. */
 205         if((SCI0CR2 & SCICR2_TX_ISR_ENABLE) && (flags & SCISR1_TX_REGISTER_EMPTY)){
 206                 /* Get the byte to be sent from the buffer */
 207                 unsigned char rawValue = *TXBufferCurrentPositionSCI0;
 208
 209                 if(TXBufferCurrentPositionSCI0 <= TXBufferCurrentPositionHandler){
 210                         if(TXByteEscaped == 0){
 211                                 /* If the raw value needs to be escaped */
 212                                 if(rawValue == ESCAPE_BYTE){
 213                                         SCI0DRL = ESCAPE_BYTE;
 214                                         TXByteEscaped = ESCAPED_ESCAPE_BYTE;
 215                                 }else if(rawValue == START_BYTE){
 216                                         SCI0DRL = ESCAPE_BYTE;
 217                                         TXByteEscaped = ESCAPED_START_BYTE;
 218                                 }else if(rawValue == STOP_BYTE){
 219                                         SCI0DRL = ESCAPE_BYTE;
 220                                         TXByteEscaped = ESCAPED_STOP_BYTE;
 221                                 }else{ /* Otherwise just send it */
 222                                         SCI0DRL = rawValue;
 223                                         TXBufferCurrentPositionSCI0++;
 224                                 }
 225                         }else{
 226                                 SCI0DRL = TXByteEscaped;
 227                                 TXBufferCurrentPositionSCI0++;
 228                                 TXByteEscaped = 0;
 229                         }
 230                 }else{ /* Length is zero */
 231                         if(coreStatusA & BIT7){
 232                                 /* Turn off transmission interrupt */
 233                                 SCI0CR2 &= (SCICR2_TX_ISR_DISABLE & SCICR2_TX_DISABLE);
 234                                 /* Clear the TX in progress flag */
 235                                 TXBufferInUseFlags &= COM_CLEAR_SCI0_INTERFACE_ID;
 236                                 coreStatusA &= NBIT7;
 237                         }else{
 238                                 coreStatusA |= BIT7;
 239                                 /* Send the stop byte */
 240                                 SCI0DRL = STOP_BYTE;
 241                         }
 242                 }
 243         }
 244
 245         DEBUG_TURN_PIN_OFF(DECODER_BENCHMARKS, NBIT4, PORTB);
 246 }