skarg
223 lines
7.0 KiB
C
223 lines
7.0 KiB
C
/**************************************************************************
|
|
*
|
|
* Copyright (C) 2007 Steve Karg <skarg@users.sourceforge.net>
|
|
* RS-485 initialization on AT91SAM7S inspired by Keil Eletronik serial.c
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining
|
|
* a copy of this software and associated documentation files (the
|
|
* "Software"), to deal in the Software without restriction, including
|
|
* without limitation the rights to use, copy, modify, merge, publish,
|
|
* distribute, sublicense, and/or sell copies of the Software, and to
|
|
* permit persons to whom the Software is furnished to do so, subject to
|
|
* the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included
|
|
* in all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
|
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
|
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
|
|
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
|
|
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
|
|
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
|
|
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
|
|
*
|
|
*********************************************************************/
|
|
|
|
/* The module handles sending data out the RS-485 port */
|
|
/* and handles receiving data from the RS-485 port. */
|
|
/* Customize this file for your specific hardware */
|
|
#include <stddef.h>
|
|
#include <stdint.h>
|
|
#include <stdbool.h>
|
|
#include <stdlib.h>
|
|
#include <stdio.h>
|
|
#include "mstp.h"
|
|
|
|
/* This file has been customized for use with UART0
|
|
on the AT91SAM7S-EK */
|
|
#include "board.h"
|
|
|
|
/* UART */
|
|
static volatile AT91S_USART *RS485_Interface = AT91C_BASE_US0;
|
|
/* baud rate */
|
|
static int RS485_Baud = 38400;
|
|
|
|
/****************************************************************************
|
|
* DESCRIPTION: Sets the interface - UART0 or UART1 or...
|
|
* RETURN: none
|
|
* ALGORITHM: none
|
|
* NOTES: none
|
|
*****************************************************************************/
|
|
void RS485_Set_Interface(char *ifname)
|
|
{
|
|
RS485_Interface = (volatile AT91S_USART *)ifname;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* DESCRIPTION: Initializes the RS485 hardware and variables, and starts in
|
|
* receive mode.
|
|
* RETURN: none
|
|
* ALGORITHM: none
|
|
* NOTES: none
|
|
*****************************************************************************/
|
|
void RS485_Initialize(void)
|
|
{
|
|
// enable the USART0 peripheral clock
|
|
volatile AT91PS_PMC pPMC = AT91C_BASE_PMC;
|
|
pPMC->PMC_PCER = pPMC->PMC_PCSR | (1<<AT91C_ID_US0);
|
|
|
|
/* enable the peripheral by disabling the pin in the PIO controller */
|
|
*AT91C_PIOA_PDR = AT91C_PA5_RXD0 | AT91C_PA6_TXD0 | AT91C_PA7_RTS0;
|
|
|
|
RS485_Interface->US_CR =
|
|
AT91C_US_RSTRX | /* Reset Receiver */
|
|
AT91C_US_RSTTX | /* Reset Transmitter */
|
|
AT91C_US_RXDIS | /* Receiver Disable */
|
|
AT91C_US_TXDIS; /* Transmitter Disable */
|
|
|
|
RS485_Interface->US_MR =
|
|
AT91C_US_USMODE_RS485 | /* RS-485 Mode - RTS auto assert */
|
|
AT91C_US_CLKS_CLOCK | /* Clock = MCK */
|
|
AT91C_US_CHRL_8_BITS | /* 8-bit Data */
|
|
AT91C_US_PAR_NONE | /* No Parity */
|
|
AT91C_US_NBSTOP_1_BIT; /* 1 Stop Bit */
|
|
|
|
/* set the Time Guard to release RTS after x bit times */
|
|
RS485_Interface->US_TTGR = 4;
|
|
|
|
/* baud rate */
|
|
RS485_Interface->US_BRGR = MCK/16/RS485_Baud;
|
|
|
|
RS485_Interface->US_CR =
|
|
AT91C_US_RXEN | /* Receiver Enable */
|
|
AT91C_US_TXEN; /* Transmitter Enable */
|
|
|
|
return;
|
|
}
|
|
|
|
void RS485_Cleanup(void)
|
|
{
|
|
|
|
}
|
|
|
|
/****************************************************************************
|
|
* DESCRIPTION: Returns the baud rate that we are currently running at
|
|
* RETURN: none
|
|
* ALGORITHM: none
|
|
* NOTES: none
|
|
*****************************************************************************/
|
|
uint32_t RS485_Get_Baud_Rate(void)
|
|
{
|
|
return RS485_Baud;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* DESCRIPTION: Sets the baud rate for the chip USART
|
|
* RETURN: none
|
|
* ALGORITHM: none
|
|
* NOTES: none
|
|
*****************************************************************************/
|
|
bool RS485_Set_Baud_Rate(uint32_t baud)
|
|
{
|
|
bool valid = true;
|
|
|
|
switch (baud) {
|
|
case 9600:
|
|
case 19200:
|
|
case 38400:
|
|
case 57600:
|
|
case 115200:
|
|
RS485_Baud = baud;
|
|
RS485_Interface->US_BRGR = MCK/16/baud;
|
|
/* FIXME: store the baud rate */
|
|
break;
|
|
default:
|
|
valid = false;
|
|
break;
|
|
}
|
|
|
|
return valid;
|
|
}
|
|
|
|
/* Transmits a Frame on the wire */
|
|
void RS485_Send_Frame(
|
|
volatile struct mstp_port_struct_t *mstp_port, /* port specific data */
|
|
uint8_t * buffer, /* frame to send (up to 501 bytes of data) */
|
|
uint16_t nbytes) /* number of bytes of data (up to 501) */
|
|
{
|
|
uint8_t turnaround_time;
|
|
|
|
/* toggle LED on send */
|
|
volatile AT91PS_PIO pPIO = AT91C_BASE_PIOA;
|
|
/* LED ON */
|
|
pPIO->PIO_CODR = LED1;
|
|
/* delay after reception - per MS/TP spec */
|
|
if (mstp_port) {
|
|
/* wait about 40 bit times since reception */
|
|
turnaround_time = (40*1000)/RS485_Baud;
|
|
if (!turnaround_time) {
|
|
turnaround_time = 1;
|
|
}
|
|
while (mstp_port->SilenceTimer < turnaround_time) {
|
|
/* do nothing - wait for timer to increment */
|
|
};
|
|
}
|
|
while (nbytes) {
|
|
while (!(RS485_Interface->US_CSR & AT91C_US_TXRDY)) {
|
|
/* do nothing - wait until Tx buffer is empty */
|
|
}
|
|
RS485_Interface->US_THR = *buffer;
|
|
buffer++;
|
|
nbytes--;
|
|
/* per MSTP spec */
|
|
if (mstp_port) {
|
|
mstp_port->SilenceTimer = 0;
|
|
}
|
|
}
|
|
while (!(RS485_Interface->US_CSR & AT91C_US_TXRDY)) {
|
|
/* do nothing - wait until Tx buffer is empty */
|
|
}
|
|
/* LED OFF */
|
|
pPIO->PIO_SODR = LED1;
|
|
|
|
return;
|
|
}
|
|
|
|
/* called by timer, interrupt(?) or other thread */
|
|
void RS485_Check_UART_Data(struct mstp_port_struct_t *mstp_port)
|
|
{
|
|
if (mstp_port->ReceiveError == true) {
|
|
/* wait for state machine to clear this */
|
|
}
|
|
/* wait for state machine to read from the DataRegister */
|
|
else if (mstp_port->DataAvailable == false) {
|
|
/* check for data */
|
|
if ( RS485_Interface->US_CSR & AT91C_US_RXRDY) {
|
|
mstp_port->DataRegister = RS485_Interface->US_RHR;
|
|
mstp_port->DataAvailable = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
#ifdef TEST_RS485
|
|
static struct mstp_port_struct_t MSTP_Port;
|
|
|
|
int main(void)
|
|
{
|
|
unsigned i = 0;
|
|
|
|
RS485_Set_Baud_Rate(38400);
|
|
RS485_Initialize();
|
|
/* receive task */
|
|
for (;;) {
|
|
RS485_Check_UART_Data(&MSTP_Port);
|
|
if (MSTP_Port.DataAvailable) {
|
|
fprintf(stderr,"%02X ",MSTP_Port.DataRegister);
|
|
MSTP_Port.DataAvailable = false;
|
|
}
|
|
}
|
|
}
|
|
#endif /* TEST_ABORT */
|
|
|