252 lines
11 KiB
C
252 lines
11 KiB
C
/****************************************************************************************
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| Description: bootloader UART communication interface source file
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| File Name: uart.c
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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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| 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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| 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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| You should have received a copy of the GNU General Public License along with OpenBLT.
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| If not, see <http://www.gnu.org/licenses/>.
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| A special exception to the GPL is included to allow you to distribute a combined work
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| that includes OpenBLT without being obliged to provide the source code for any
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| proprietary components. The exception text is included at the bottom of the license
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| file <license.html>.
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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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#define UART_DLAB (0x80) /* divisor latch access bit */
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#define UART_MODE_8N1 (0x03) /* 8 data and 1 stop bit, no parity */
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#define UART_FIFO_RX1 (0x07) /* FIFO reset and RX FIFO 1 deep */
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#define UART_RDR (0x01) /* receiver data ready */
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#define UART_THRE (0x20) /* transmitter holding register empty */
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/****************************************************************************************
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* Register definitions
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****************************************************************************************/
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#define U0RBR (*((volatile blt_int8u *) 0xE000C000))
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#define U0THR (*((volatile blt_int8u *) 0xE000C000))
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#define U0IER (*((volatile blt_int8u *) 0xE000C004))
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#define U0IIR (*((volatile blt_int8u *) 0xE000C008))
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#define U0FCR (*((volatile blt_int8u *) 0xE000C008))
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#define U0LCR (*((volatile blt_int8u *) 0xE000C00C))
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#define U0LSR (*((volatile blt_int8u *) 0xE000C014))
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#define U0SCR (*((volatile blt_int8u *) 0xE000C01C))
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#define U0DLL (*((volatile blt_int8u *) 0xE000C000))
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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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** NAME: UartInit
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** PARAMETER: none
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** RETURN VALUE: none
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** DESCRIPTION: Initializes the UART communication interface
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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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** NAME: UartTransmitPacket
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** PARAMETER: data pointer to byte array with data that it to be transmitted.
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** len number of bytes that are to be transmitted.
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** RETURN VALUE: none
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** DESCRIPTION: Transmits a packet formatted for the communication interface.
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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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/* verify validity of the len-paramenter */
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ASSERT_RT(len <= BOOT_COM_TX_MAX_DATA);
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/* first transmit the length of the packet */
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ASSERT_RT(UartTransmitByte(len) == 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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ASSERT_RT(UartTransmitByte(data[data_index]) == BLT_TRUE);
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}
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} /*** end of UartTransmitPacket ***/
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/****************************************************************************************
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** NAME: UartReceivePacket
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** PARAMETER: data pointer to byte array where the data is to be stored.
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** RETURN VALUE: BLT_TRUE if a packet was received, BLT_FALSE otherwise.
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** DESCRIPTION: Receives a communication interface packet if one is present.
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**
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****************************************************************************************/
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blt_bool UartReceivePacket(blt_int8u *data)
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{
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static blt_int8u xcpCtoReqPacket[XCP_CTO_PACKET_LEN+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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/* 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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/* indicate that a cto packet is being received */
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xcpCtoRxInProgress = BLT_TRUE;
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/* reset packet data count */
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xcpCtoRxLength = 0;
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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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/* packet reception complete */
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return BLT_TRUE;
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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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** NAME: UartReceiveByte
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** PARAMETER: data pointer to byte where the data is to be stored.
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** RETURN VALUE: BLT_TRUE if a byte was received, BLT_FALSE otherwise.
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** DESCRIPTION: Receives a communication interface byte if one is present.
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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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** NAME: UartTransmitByte
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** PARAMETER: data value of byte that is to be transmitted.
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** RETURN VALUE: BLT_TRUE if the byte was transmitted, BLT_FALSE otherwise.
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** DESCRIPTION: Transmits a communication interface byte.
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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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/* 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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/* 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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}
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/* byte transmitted */
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return BLT_TRUE;
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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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