288 lines
12 KiB
C
288 lines
12 KiB
C
/************************************************************************************//**
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* \file Source\HCS12\uart.c
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* \brief Bootloader UART communication interface source file.
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* \ingroup Target_HCS12
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* \internal
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*----------------------------------------------------------------------------------------
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* C O P Y R I G H T
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*----------------------------------------------------------------------------------------
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* Copyright (c) 2013 by Feaser http://www.feaser.com All rights reserved
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*
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*----------------------------------------------------------------------------------------
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* L I C E N S E
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*----------------------------------------------------------------------------------------
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* This file is part of OpenBLT. OpenBLT is free software: you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as published by the Free
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* Software Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* OpenBLT is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU General Public License for more details.
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*
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* You have received a copy of the GNU General Public License along with OpenBLT. It
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* should be located in ".\Doc\license.html". If not, contact Feaser to obtain a copy.
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*
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* \endinternal
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****************************************************************************************/
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/****************************************************************************************
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* Include files
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****************************************************************************************/
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#include "boot.h" /* bootloader generic header */
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#if (BOOT_COM_UART_ENABLE > 0)
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/****************************************************************************************
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* Type definitions
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****************************************************************************************/
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/** \brief Structure type with the layout of the UART related control registers. */
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typedef volatile struct
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{
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volatile blt_int8u scibdh; /**< baudrate control register [SBR 12..8] */
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volatile blt_int8u scibdl; /**< baudrate control register [SBR 8..0] */
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volatile blt_int8u scicr1; /**< control register 1 */
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volatile blt_int8u scicr2; /**< control register 2 */
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volatile blt_int8u scisr1; /**< status regsiter 1 */
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volatile blt_int8u scisr2; /**< status register 2 */
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volatile blt_int8u scidrh; /**< data register high (for ninth bit) */
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volatile blt_int8u scidrl; /**< data regsiter low */
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} tUartRegs; /**< sci related registers */
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/****************************************************************************************
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* Macro definitions
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****************************************************************************************/
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/** \brief Timeout time for the reception of a CTO packet. The timer is started upon
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* reception of the first packet byte.
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*/
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#define UART_CTO_RX_PACKET_TIMEOUT_MS (100u)
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/** \brief Timeout for transmitting a byte in milliseconds. */
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#define UART_BYTE_TX_TIMEOUT_MS (10u)
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#if (BOOT_COM_UART_CHANNEL_INDEX == 0)
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/** \brief Set UART base address to SCI0. */
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#define UART_REGS_BASE_ADDRESS (0x00c8)
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#elif (BOOT_COM_UART_CHANNEL_INDEX == 1)
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/** \brief Set UART base address to SCI1. */
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#define UART_REGS_BASE_ADDRESS (0x00d0)
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#endif
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/** \brief Macro for accessing the UART related control registers. */
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#define UART ((volatile tUartRegs *)UART_REGS_BASE_ADDRESS)
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/****************************************************************************************
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* Register definitions
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****************************************************************************************/
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/** \brief SCICR2 - transmitter enable bit. */
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#define TE_BIT (0x08)
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/** \brief SCICR2 - receiver enable bit. */
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#define RE_BIT (0x04)
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/** \brief SCISR1 - receiver data register full bit. */
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#define RDRF_BIT (0x20)
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/** \brief SCISR1 - transmit data register empty bit. */
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#define TDRE_BIT (0x80)
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/****************************************************************************************
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* Function prototypes
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****************************************************************************************/
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static blt_bool UartReceiveByte(blt_int8u *data);
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static blt_bool UartTransmitByte(blt_int8u data);
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/************************************************************************************//**
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** \brief Initializes the UART communication interface.
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** \return none.
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**
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****************************************************************************************/
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void UartInit(void)
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{
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blt_int16u baudrate_sbr0_12;
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/* the current implementation supports SCI0 and SCI1. throw an assertion error in
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* case a different UART channel is configured.
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*/
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ASSERT_CT((BOOT_COM_UART_CHANNEL_INDEX == 0) || (BOOT_COM_UART_CHANNEL_INDEX == 1));
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/* reset the SCI subsystem's configuration, which automatically configures it for
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* 8,n,1 communication mode.
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*/
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UART->scicr2 = 0;
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UART->scicr1 = 0;
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UART->scibdh = 0;
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UART->scibdl = 0;
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/* configure the baudrate from BOOT_COM_UART_BAUDRATE */
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baudrate_sbr0_12 = (BOOT_CPU_SYSTEM_SPEED_KHZ * 1000ul) / 16 / BOOT_COM_UART_BAUDRATE;
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/* baudrate register value cannot be more than 13 bits */
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ASSERT_RT((baudrate_sbr0_12 & 0xe000) == 0);
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/* write first MSB then LSB for the baudrate to latch */
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UART->scibdh = (blt_int8u)(baudrate_sbr0_12 >> 8);
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UART->scibdl = (blt_int8u)baudrate_sbr0_12;
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/* enable the transmitted and receiver */
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UART->scicr2 |= (TE_BIT | RE_BIT);
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} /*** end of UartInit ***/
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/************************************************************************************//**
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** \brief Transmits a packet formatted for the communication interface.
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** \param data Pointer to byte array with data that it to be transmitted.
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** \param len Number of bytes that are to be transmitted.
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** \return none.
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**
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****************************************************************************************/
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void UartTransmitPacket(blt_int8u *data, blt_int8u len)
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{
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blt_int16u data_index;
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blt_bool result;
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/* verify validity of the len-paramenter */
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ASSERT_RT(len <= BOOT_COM_UART_TX_MAX_DATA);
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/* first transmit the length of the packet */
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result = UartTransmitByte(len);
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ASSERT_RT(result == BLT_TRUE);
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/* transmit all the packet bytes one-by-one */
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for (data_index = 0; data_index < len; data_index++)
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{
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/* keep the watchdog happy */
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CopService();
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/* write byte */
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result = UartTransmitByte(data[data_index]);
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ASSERT_RT(result == BLT_TRUE);
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}
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} /*** end of UartTransmitPacket ***/
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/************************************************************************************//**
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** \brief Receives a communication interface packet if one is present.
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** \param data Pointer to byte array where the data is to be stored.
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** \param len Pointer where the length of the packet is to be stored.
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** \return BLT_TRUE if a packet was received, BLT_FALSE otherwise.
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**
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****************************************************************************************/
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blt_bool UartReceivePacket(blt_int8u *data, blt_int8u *len)
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{
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static blt_int8u xcpCtoReqPacket[BOOT_COM_UART_RX_MAX_DATA+1]; /* one extra for length */
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static blt_int8u xcpCtoRxLength;
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static blt_bool xcpCtoRxInProgress = BLT_FALSE;
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static blt_int32u xcpCtoRxStartTime = 0;
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/* start of cto packet received? */
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if (xcpCtoRxInProgress == BLT_FALSE)
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{
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/* store the message length when received */
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if (UartReceiveByte(&xcpCtoReqPacket[0]) == BLT_TRUE)
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{
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if ( (xcpCtoReqPacket[0] > 0) &&
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(xcpCtoReqPacket[0] <= BOOT_COM_UART_RX_MAX_DATA) )
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{
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/* store the start time */
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xcpCtoRxStartTime = TimerGet();
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/* reset packet data count */
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xcpCtoRxLength = 0;
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/* indicate that a cto packet is being received */
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xcpCtoRxInProgress = BLT_TRUE;
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}
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}
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}
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else
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{
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/* store the next packet byte */
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if (UartReceiveByte(&xcpCtoReqPacket[xcpCtoRxLength+1]) == BLT_TRUE)
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{
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/* increment the packet data count */
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xcpCtoRxLength++;
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/* check to see if the entire packet was received */
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if (xcpCtoRxLength == xcpCtoReqPacket[0])
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{
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/* copy the packet data */
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CpuMemCopy((blt_int32u)data, (blt_int32u)&xcpCtoReqPacket[1], xcpCtoRxLength);
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/* done with cto packet reception */
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xcpCtoRxInProgress = BLT_FALSE;
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/* set the packet length */
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*len = xcpCtoRxLength;
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/* packet reception complete */
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return BLT_TRUE;
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}
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}
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else
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{
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/* check packet reception timeout */
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if (TimerGet() > (xcpCtoRxStartTime + UART_CTO_RX_PACKET_TIMEOUT_MS))
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{
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/* cancel cto packet reception due to timeout. note that that automaticaly
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* discards the already received packet bytes, allowing the host to retry.
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*/
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xcpCtoRxInProgress = BLT_FALSE;
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}
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}
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}
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/* packet reception not yet complete */
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return BLT_FALSE;
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} /*** end of UartReceivePacket ***/
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/************************************************************************************//**
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** \brief Receives a communication interface byte if one is present.
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** \param data Pointer to byte where the data is to be stored.
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** \return BLT_TRUE if a byte was received, BLT_FALSE otherwise.
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**
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****************************************************************************************/
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static blt_bool UartReceiveByte(blt_int8u *data)
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{
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/* check if a new byte was received by means of the RDRF-bit */
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if ((UART->scisr1 & RDRF_BIT) != 0)
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{
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/* store the received byte */
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data[0] = UART->scidrl;
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/* inform caller of the newly received byte */
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return BLT_TRUE;
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}
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/* inform caller that no new data was received */
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return BLT_FALSE;
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} /*** end of UartReceiveByte ***/
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/************************************************************************************//**
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** \brief Transmits a communication interface byte.
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** \param data Value of byte that is to be transmitted.
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** \return BLT_TRUE if the byte was transmitted, BLT_FALSE otherwise.
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**
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****************************************************************************************/
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static blt_bool UartTransmitByte(blt_int8u data)
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{
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blt_int32u timeout;
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blt_bool result = BLT_TRUE;
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/* check if tx holding register can accept new data */
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if ((UART->scisr1 & TDRE_BIT) == 0)
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{
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/* UART not ready. should not happen */
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return BLT_FALSE;
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}
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/* write byte to transmit holding register */
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UART->scidrl = data;
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/* set timeout time to wait for transmit completion. */
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timeout = TimerGet() + UART_BYTE_TX_TIMEOUT_MS;
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/* wait for tx holding register to be empty */
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while ((UART->scisr1 & TDRE_BIT) == 0)
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{
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/* keep the watchdog happy */
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CopService();
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/* break loop upon timeout. this would indicate a hardware failure. */
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if (TimerGet() > timeout)
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{
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result = BLT_FALSE;
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break;
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}
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}
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/* give the result back to the caller */
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return result;
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} /*** end of UartTransmitByte ***/
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#endif /* BOOT_COM_UART_ENABLE > 0 */
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/*********************************** end of uart.c *************************************/
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