freemaster_serial.rar_MC9S12 SCI_freemaster_mc9s12

/****************************************************************************** * * Freescale Semiconductor Inc. * (c) Copyright 2004-2010 Freescale Semiconductor * ALL RIGHTS RESERVED. * ****************************************************************************//*! * * @file freemaster_serial.c * * @brief FreeMASTER SCI communication routines * * @version 1.1.22.0 * * @date Apr-23-2010 * *******************************************************************************/ #include "freemaster.h" #include "freemaster_private.h" #include "freemaster_protocol.h" #if FMSTR_USE_SCI || FMSTR_USE_JTAG /*********************************** * local variables ***********************************/ /* FreeMASTER communication buffer (in/out) plus the STS and LEN bytes */ static FMSTR_BCHR pcm_pCommBuffer[FMSTR_COMM_BUFFER_SIZE+3]; /* FreeMASTER runtime flags */ /*lint -e{960} using union */ typedef volatile union { FMSTR_FLAGS all; struct { unsigned bTxActive : 1; /* response is being transmitted */ unsigned bTxWaitTC : 1; /* response sent, wait for transmission complete */ unsigned bTxLastCharSOB : 1; /* last transmitted char was equal to SOB */ unsigned bRxLastCharSOB : 1; /* last received character was SOB */ unsigned bRxMsgLengthNext : 1; /* expect the length byte next time */ unsigned bJtagRIEPending : 1; /* JTAG RIE bit failed to be set, try again later */ } flg; } FMSTR_SERIAL_FLAGS; static FMSTR_SERIAL_FLAGS pcm_wFlags; /* receive and transmit buffers and counters */ static FMSTR_SIZE8 pcm_nTxTodo; /* transmission to-do counter (0 when tx is idle) */ static FMSTR_SIZE8 pcm_nRxTodo; /* reception to-do counter (0 when rx is idle) */ static FMSTR_BPTR pcm_pTxBuff; /* pointer to next byte to transmit */ static FMSTR_BPTR pcm_pRxBuff; /* pointer to next free place in RX buffer */ static FMSTR_BCHR pcm_nRxCheckSum; /* checksum of data being received */ /* SHORT_INTR receive queue (circular buffer) */ #if FMSTR_SHORT_INTR static FMSTR_BCHR pcm_pRQueueBuffer[FMSTR_COMM_RQUEUE_SIZE]; static FMSTR_BPTR pcm_pRQueueRP; /* SHORT_INTR queue read-pointer */ static FMSTR_BPTR pcm_pRQueueWP; /* SHORT_INTR queue write-pointer */ #endif #if FMSTR_USE_JTAG static FMSTR_U32 pcm_wJtagTxData; /* four bytes buffer to be sent over JTAG (LSB first) */ static FMSTR_SIZE8 pcm_wJtagTxCtr; /* counter of bytes in pcm_wJtagTxData */ #endif /*********************************** * local function prototypes ***********************************/ static void FMSTR_Listen(void); static void FMSTR_SendError(FMSTR_BCHR nErrCode); static void FMSTR_Tx(void); static void FMSTR_Rx(FMSTR_BCHR nRxChar); static void FMSTR_RxQueue(FMSTR_BCHR nRxChar); static void FMSTR_RxDequeue(void); /*lint -esym(752,FMSTR_RxQueue) this may be unreferenced in some cases */ /*lint -esym(752,FMSTR_RxDequeue) this may be unreferenced in some cases */ /**************************************************************************//*! * * @brief Serial communication initialization * ******************************************************************************/ void FMSTR_InitSerial(void) { /* initialize all state variables */ pcm_wFlags.all = 0U; pcm_nTxTodo = 0U; #if FMSTR_USE_SCI && FMSTR_SCI_TWOWIRE_ONLY /* to enable TX and RX together in FreeMASTER initialization */ FMSTR_SCI_TE_RE(); #endif #if FMSTR_SHORT_INTR pcm_pRQueueRP = pcm_pRQueueBuffer; pcm_pRQueueWP = pcm_pRQueueBuffer; #endif /* start listening for commands */ FMSTR_Listen(); } /**************************************************************************//*! * * @brief Start listening on a serial line * * Reset the receiver machine and start listening on a serial line * ******************************************************************************/ static void FMSTR_Listen(void) { pcm_nRxTodo = 0U; /* disable transmitter state machine */ pcm_wFlags.flg.bTxActive = 0U; pcm_wFlags.flg.bTxWaitTC = 0U; /* disable transmitter, enable receiver (enables single-wire connection) */ #if FMSTR_USE_SCI && !FMSTR_SCI_TWOWIRE_ONLY FMSTR_SCI_TD(); FMSTR_SCI_RE(); #endif /* disable transmit, enable receive interrupts */ #if FMSTR_SHORT_INTR || FMSTR_LONG_INTR #if FMSTR_USE_SCI FMSTR_SCI_DTXI(); /* disable SCI transmit interrupt */ FMSTR_SCI_ERXI(); /* enable SCI recieve interrupt */ #elif FMSTR_USE_JTAG FMSTR_JTAG_DTXI(); /* disable JTAG transmit interrupt */ FMSTR_JTAG_ERXI(); /* enable JTAG recieve interrupt */ /* RIE bit is forced low by HW until EONCE is first accesed, we will try again in FMSTR_Poll */ if(!FMSTR_JTAG_ERXI_CHECK()) pcm_wFlags.flg.bJtagRIEPending = 1; #endif #endif } /**************************************************************************//*! * * @brief Send response of given error code (no data) * * @param nErrCode - error code to be sent * ******************************************************************************/ static void FMSTR_SendError(FMSTR_BCHR nErrCode) { /* fill & send single-byte response */ *pcm_pCommBuffer = nErrCode; FMSTR_SendResponse(pcm_pCommBuffer, 1U); } /**************************************************************************//*! * * @brief Finalize transmit buffer before transmitting * * @param nLength - response length (1 for status + data length) * * * This Function takes the data already prepared in the transmit buffer * (inlcuding the status byte). It computes the check sum and kicks on tx. * ******************************************************************************/ void FMSTR_SendResponse(FMSTR_BPTR pResponse, FMSTR_SIZE8 nLength) { FMSTR_U16 chSum = 0U; FMSTR_U8 i, c; /* remeber the buffer to be sent */ pcm_pTxBuff = pResponse; /* status byte and data are already there, compute checksum only */ for (i=0U; i<nLength; i++) { c = 0U; pResponse = FMSTR_ValueFromBuffer8(&c, pResponse); /* add character to checksum */ chSum += c; /* prevent saturation to happen on DSP platforms */ chSum &= 0xffU; } /* store checksum after the message */ pResponse = FMSTR_ValueToBuffer8(pResponse, (FMSTR_U8) (((FMSTR_U16)~(chSum)) + 1U)); /* send the message and the checksum and the SOB */ pcm_nTxTodo = (FMSTR_SIZE8) (nLength + 1U); /* now transmitting the response */ pcm_wFlags.flg.bTxActive = 1U; pcm_wFlags.flg.bTxWaitTC = 0U; /* do not replicate the initial SOB */ pcm_wFlags.flg.bTxLastCharSOB = 0U; #if FMSTR_USE_SCI { /*lint -esym(550, dummySR) */ volatile FMSTR_SCISR dummySR; /* disable receiver, enable transmitter (single-wire communication) */ #if !FMSTR_SCI_TWOWIRE_ONLY FMSTR_SCI_RD(); FMSTR_SCI_TE(); #endif /* kick on the SCI transmission (also clears TX Empty flag on some platforms) */ dummySR = FMSTR_SCI_GETSR(); FMSTR_SCI_PUTCHAR(FMSTR_SOB); } #elif FMSTR_USE_JTAG /* kick on the JTAG transmission */ pcm_wJtagTxData = FMSTR_SOB; pcm_wJtagTxCtr = 1U; /* send the next two bytes immediatelly (we can be sure there are two bytes) */ FMSTR_Tx(); FMSTR_Tx(); /* send the third byte (if any) or flush the 32bit JTAG word */ FMSTR_Tx(); #endif /* TX interrupt enable, RX interrupt disable */ #if FMSTR_LONG_INTR || FMSTR_SHORT_INTR #if FMSTR_USE_SCI FMSTR_SCI_DRXI(); FMSTR_SCI_ETXI(); #elif FMSTR_USE_JTAG #if FMSTR_USE_JTAG_TXFIX /* in TX-bugfix mode