297 lines
12 KiB
C
297 lines
12 KiB
C
/************************************************************************************//**
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* \file Source\ARM7_LPC2000\uart.c
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* \brief Bootloader UART communication interface source file.
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* \ingroup Target_ARM7_LPC2000
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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) 2011 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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* 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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/** \brief Divisor latch access bit. */
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#define UART_DLAB (0x80)
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/** \brief 8 data and 1 stop bit, no parity. */
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#define UART_MODE_8N1 (0x03)
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/** \brief FIFO reset and RX FIFO 1 deep. */
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#define UART_FIFO_RX1 (0x07)
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/** \brief Receiver data ready. */
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#define UART_RDR (0x01)
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/** \brief Transmitter holding register empty. */
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#define UART_THRE (0x20)
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/****************************************************************************************
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* Register definitions
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****************************************************************************************/
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/** \brief U0RBR UART register. */
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#define U0RBR (*((volatile blt_int8u *) 0xE000C000))
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/** \brief U0THR UART register. */
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#define U0THR (*((volatile blt_int8u *) 0xE000C000))
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/** \brief U0IER UART register. */
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#define U0IER (*((volatile blt_int8u *) 0xE000C004))
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/** \brief U0IIR UART register. */
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#define U0IIR (*((volatile blt_int8u *) 0xE000C008))
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/** \brief U0FCR UART register. */
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#define U0FCR (*((volatile blt_int8u *) 0xE000C008))
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/** \brief U0LCR UART register. */
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#define U0LCR (*((volatile blt_int8u *) 0xE000C00C))
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/** \brief U0LSR UART register. */
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#define U0LSR (*((volatile blt_int8u *) 0xE000C014))
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/** \brief U0SCR UART register. */
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#define U0SCR (*((volatile blt_int8u *) 0xE000C01C))
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/** \brief U0DLL UART register. */
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#define U0DLL (*((volatile blt_int8u *) 0xE000C000))
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/** \brief U0DLM UART register. */
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#define U0DLM (*((volatile blt_int8u *) 0xE000C004))
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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_int32u baud_reg_value; /* baudrate register value */
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/* the current implementation supports UART0. throw an assertion error in case
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* a different UART channel is configured.
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*/
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ASSERT_CT(BOOT_COM_UART_CHANNEL_INDEX == 0);
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/* disable UART related interrupt generation. this driver works in polling mode */
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U0IER = 0;
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/* clear interrupt id register */
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U0IIR = 0;
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/* clear line status register */
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U0LSR = 0;
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/* set divisor latch DLAB = 1 so buadrate can be configured */
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U0LCR = UART_DLAB;
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/* Baudrate calculation:
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* y = BOOT_CPU_SYSTEM_SPEED_KHZ * 1000 / 16 / BOOT_COM_UART_BAUDRATE and add
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* smartness to automatically round the value up/down using the following trick:
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* y = x/n can round with y = (x + (n + 1)/2 ) / n
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*/
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/* check that baudrate register value is not 0 */
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ASSERT_CT((((BOOT_CPU_SYSTEM_SPEED_KHZ*1000/16)+((BOOT_COM_UART_BAUDRATE+1)/2))/ \
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BOOT_COM_UART_BAUDRATE) > 0);
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/* check that baudrate register value is not greater than max 16-bit unsigned value */
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ASSERT_CT((((BOOT_CPU_SYSTEM_SPEED_KHZ*1000/16)+((BOOT_COM_UART_BAUDRATE+1)/2))/ \
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BOOT_COM_UART_BAUDRATE) <= 65535);
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baud_reg_value = (((BOOT_CPU_SYSTEM_SPEED_KHZ*1000/16)+ \
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((BOOT_COM_UART_BAUDRATE+1)/2))/BOOT_COM_UART_BAUDRATE);
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/* write the calculated baudrate selector value to the registers */
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U0DLL = (blt_int8u)baud_reg_value;
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U0DLM = (blt_int8u)(baud_reg_value >> 8);
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/* configure 8 data bits, no parity and 1 stop bit and set DLAB = 0 */
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U0LCR = UART_MODE_8N1;
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/* enable and reset transmit and receive FIFO. necessary for UART operation */
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U0FCR = UART_FIFO_RX1;
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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 RDR-bit */
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if ((U0LSR & UART_RDR) != 0)
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{
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/* store the received byte */
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data[0] = U0RBR;
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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 ((U0LSR & UART_THRE) == 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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U0THR = 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 ((U0LSR & UART_THRE) == 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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