/****************************************************************************************
| Description: bootloader UART communication interface source file
| File Name: uart.c
|
|----------------------------------------------------------------------------------------
| C O P Y R I G H T
|----------------------------------------------------------------------------------------
| Copyright (c) 2011 by Feaser http://www.feaser.com All rights reserved
|
|----------------------------------------------------------------------------------------
| L I C E N S E
|----------------------------------------------------------------------------------------
| This file is part of OpenBLT. OpenBLT is free software: you can redistribute it and/or
| modify it under the terms of the GNU General Public License as published by the Free
| Software Foundation, either version 3 of the License, or (at your option) any later
| version.
|
| OpenBLT is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
| without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
| PURPOSE. See the GNU General Public License for more details.
|
| You should have received a copy of the GNU General Public License along with OpenBLT.
| If not, see .
|
| A special exception to the GPL is included to allow you to distribute a combined work
| that includes OpenBLT without being obliged to provide the source code for any
| proprietary components. The exception text is included at the bottom of the license
| file .
|
****************************************************************************************/
/****************************************************************************************
* Include files
****************************************************************************************/
#include "boot.h" /* bootloader generic header */
#if (BOOT_COM_UART_ENABLE > 0)
/****************************************************************************************
* Macro definitions
****************************************************************************************/
#define UART_DLAB (0x80) /* divisor latch access bit */
#define UART_MODE_8N1 (0x03) /* 8 data and 1 stop bit, no parity */
#define UART_FIFO_RX1 (0x07) /* FIFO reset and RX FIFO 1 deep */
#define UART_RDR (0x01) /* receiver data ready */
#define UART_THRE (0x20) /* transmitter holding register empty */
/****************************************************************************************
* Register definitions
****************************************************************************************/
#define U0RBR (*((volatile blt_int8u *) 0xE000C000))
#define U0THR (*((volatile blt_int8u *) 0xE000C000))
#define U0IER (*((volatile blt_int8u *) 0xE000C004))
#define U0IIR (*((volatile blt_int8u *) 0xE000C008))
#define U0FCR (*((volatile blt_int8u *) 0xE000C008))
#define U0LCR (*((volatile blt_int8u *) 0xE000C00C))
#define U0LSR (*((volatile blt_int8u *) 0xE000C014))
#define U0SCR (*((volatile blt_int8u *) 0xE000C01C))
#define U0DLL (*((volatile blt_int8u *) 0xE000C000))
#define U0DLM (*((volatile blt_int8u *) 0xE000C004))
/****************************************************************************************
* Function prototypes
****************************************************************************************/
static blt_bool UartReceiveByte(blt_int8u *data);
static blt_bool UartTransmitByte(blt_int8u data);
/****************************************************************************************
** NAME: UartInit
** PARAMETER: none
** RETURN VALUE: none
** DESCRIPTION: Initializes the UART communication interface
**
****************************************************************************************/
void UartInit(void)
{
blt_int32u baud_reg_value; /* baudrate register value */
/* the current implementation supports UART0. throw an assertion error in case
* a different UART channel is configured.
*/
ASSERT_CT(BOOT_COM_UART_CHANNEL_INDEX == 0);
/* disable UART related interrupt generation. this driver works in polling mode */
U0IER = 0;
/* clear interrupt id register */
U0IIR = 0;
/* clear line status register */
U0LSR = 0;
/* set divisor latch DLAB = 1 so buadrate can be configured */
U0LCR = UART_DLAB;
/* Baudrate calculation:
* y = BOOT_CPU_SYSTEM_SPEED_KHZ * 1000 / 16 / BOOT_COM_UART_BAUDRATE and add
* smartness to automatically round the value up/down using the following trick:
* y = x/n can round with y = (x + (n + 1)/2 ) / n
*/
/* check that baudrate register value is not 0 */
ASSERT_CT((((BOOT_CPU_SYSTEM_SPEED_KHZ*1000/16)+((BOOT_COM_UART_BAUDRATE+1)/2))/ \
BOOT_COM_UART_BAUDRATE) > 0);
/* check that baudrate register value is not greater than max 16-bit unsigned value */
ASSERT_CT((((BOOT_CPU_SYSTEM_SPEED_KHZ*1000/16)+((BOOT_COM_UART_BAUDRATE+1)/2))/ \
BOOT_COM_UART_BAUDRATE) <= 65535);
baud_reg_value = (((BOOT_CPU_SYSTEM_SPEED_KHZ*1000/16)+ \
((BOOT_COM_UART_BAUDRATE+1)/2))/BOOT_COM_UART_BAUDRATE);
/* write the calculated baudrate selector value to the registers */
U0DLL = (blt_int8u)baud_reg_value;
U0DLM = (blt_int8u)(baud_reg_value >> 8);
/* configure 8 data bits, no parity and 1 stop bit and set DLAB = 0 */
U0LCR = UART_MODE_8N1;
/* enable and reset transmit and receive FIFO. necessary for UART operation */
U0FCR = UART_FIFO_RX1;
} /*** end of UartInit ***/
/****************************************************************************************
** NAME: UartTransmitPacket
** PARAMETER: data pointer to byte array with data that it to be transmitted.
** len number of bytes that are to be transmitted.
** RETURN VALUE: none
** DESCRIPTION: Transmits a packet formatted for the communication interface.
**
****************************************************************************************/
void UartTransmitPacket(blt_int8u *data, blt_int8u len)
{
blt_int16u data_index;
/* verify validity of the len-paramenter */
ASSERT_RT(len <= BOOT_COM_TX_MAX_DATA);
/* first transmit the length of the packet */
ASSERT_RT(UartTransmitByte(len) == BLT_TRUE);
/* transmit all the packet bytes one-by-one */
for (data_index = 0; data_index < len; data_index++)
{
/* keep the watchdog happy */
CopService();
/* write byte */
ASSERT_RT(UartTransmitByte(data[data_index]) == BLT_TRUE);
}
} /*** end of UartTransmitPacket ***/
/****************************************************************************************
** NAME: UartReceivePacket
** PARAMETER: data pointer to byte array where the data is to be stored.
** RETURN VALUE: BLT_TRUE if a packet was received, BLT_FALSE otherwise.
** DESCRIPTION: Receives a communication interface packet if one is present.
**
****************************************************************************************/
blt_bool UartReceivePacket(blt_int8u *data)
{
static blt_int8u xcpCtoReqPacket[XCP_CTO_PACKET_LEN+1]; /* one extra for length */
static blt_int8u xcpCtoRxLength;
static blt_bool xcpCtoRxInProgress = BLT_FALSE;
/* start of cto packet received? */
if (xcpCtoRxInProgress == BLT_FALSE)
{
/* store the message length when received */
if (UartReceiveByte(&xcpCtoReqPacket[0]) == BLT_TRUE)
{
/* indicate that a cto packet is being received */
xcpCtoRxInProgress = BLT_TRUE;
/* reset packet data count */
xcpCtoRxLength = 0;
}
}
else
{
/* store the next packet byte */
if (UartReceiveByte(&xcpCtoReqPacket[xcpCtoRxLength+1]) == BLT_TRUE)
{
/* increment the packet data count */
xcpCtoRxLength++;
/* check to see if the entire packet was received */
if (xcpCtoRxLength == xcpCtoReqPacket[0])
{
/* copy the packet data */
CpuMemCopy((blt_int32u)data, (blt_int32u)&xcpCtoReqPacket[1], xcpCtoRxLength);
/* done with cto packet reception */
xcpCtoRxInProgress = BLT_FALSE;
/* packet reception complete */
return BLT_TRUE;
}
}
}
/* packet reception not yet complete */
return BLT_FALSE;
} /*** end of UartReceivePacket ***/
/****************************************************************************************
** NAME: UartReceiveByte
** PARAMETER: data pointer to byte where the data is to be stored.
** RETURN VALUE: BLT_TRUE if a byte was received, BLT_FALSE otherwise.
** DESCRIPTION: Receives a communication interface byte if one is present.
**
****************************************************************************************/
static blt_bool UartReceiveByte(blt_int8u *data)
{
/* check if a new byte was received by means of the RDR-bit */
if((U0LSR & UART_RDR) != 0)
{
/* store the received byte */
data[0] = U0RBR;
/* inform caller of the newly received byte */
return BLT_TRUE;
}
/* inform caller that no new data was received */
return BLT_FALSE;
} /*** end of UartReceiveByte ***/
/****************************************************************************************
** NAME: UartTransmitByte
** PARAMETER: data value of byte that is to be transmitted.
** RETURN VALUE: BLT_TRUE if the byte was transmitted, BLT_FALSE otherwise.
** DESCRIPTION: Transmits a communication interface byte.
**
****************************************************************************************/
static blt_bool UartTransmitByte(blt_int8u data)
{
/* check if tx holding register can accept new data */
if ((U0LSR & UART_THRE) == 0)
{
/* UART not ready. should not happen */
return BLT_FALSE;
}
/* write byte to transmit holding register */
U0THR = data;
/* wait for tx holding register to be empty */
while((U0LSR & UART_THRE) == 0)
{
/* keep the watchdog happy */
CopService();
}
/* byte transmitted */
return BLT_TRUE;
} /*** end of UartTransmitByte ***/
#endif /* BOOT_COM_UART_ENABLE > 0 */
/*********************************** end of uart.c *************************************/