Kari Argillander
cb243c36a8
* Change MIT license texts to SPDX-License-Identifier SPDX-License-Identifier is much easier to understand and grep than license text so use that instead. * Change GPL exception license texts to SPDX-License-Identifier SPDX-License-Identifier is much easier to understand and grep than license text so use that instead. * Change misc license texts to SPDX-License-Identifier There are some external code in repo which are not licenses as most of the stuff in this repo. We still want every file to have SPDX identifier to easily grep licenses. * Add currently used license files Even though Bacnet-Stack is using SPDX identifiers we still need to give those license files with source. For this reason add all license files to license/ folder. SPDX has also files which would make same thing but this is style which example Linux kernel is using and it is quite clear so I choose that one for now. I choosed not yet bring CC-PDDC as that is not right license for those files. --------- Co-authored-by: Kari Argillander <kari.argillander@fidelix.com>
264 lines
8.3 KiB
C
264 lines
8.3 KiB
C
/**************************************************************************
|
|
*
|
|
* Copyright (C) 2007 Steve Karg <skarg@users.sourceforge.net>
|
|
* RS-485 initialization on AT91SAM7S inspired by Keil Eletronik serial.c
|
|
*
|
|
* SPDX-License-Identifier: MIT
|
|
*
|
|
*********************************************************************/
|
|
|
|
/* 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 "timer.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;
|
|
|
|
/* The minimum time after the end of the stop bit of the final octet of a */
|
|
/* received frame before a node may enable its EIA-485 driver: 40 bit times. */
|
|
/* At 9600 baud, 40 bit times would be about 4.166 milliseconds */
|
|
/* At 19200 baud, 40 bit times would be about 2.083 milliseconds */
|
|
/* At 38400 baud, 40 bit times would be about 1.041 milliseconds */
|
|
/* At 57600 baud, 40 bit times would be about 0.694 milliseconds */
|
|
/* At 76800 baud, 40 bit times would be about 0.520 milliseconds */
|
|
/* At 115200 baud, 40 bit times would be about 0.347 milliseconds */
|
|
/* 40 bits is 4 octets including a start and stop bit with each octet */
|
|
#define Tturnaround (40UL)
|
|
/* turnaround_time_milliseconds = (Tturnaround*1000UL)/RS485_Baud; */
|
|
|
|
/****************************************************************************
|
|
* DESCRIPTION: Initializes the RS485 hardware and variables, and starts in
|
|
* receive mode.
|
|
* RETURN: none
|
|
* ALGORITHM: none
|
|
* NOTES: none
|
|
*****************************************************************************/
|
|
void RS485_Initialize(void)
|
|
{
|
|
unsigned int pcsr;
|
|
/* Enable the USART0 clock in the Power Management Controller */
|
|
volatile AT91PS_PMC pPMC = AT91C_BASE_PMC;
|
|
|
|
pcsr = pPMC->PMC_PCSR;
|
|
pPMC->PMC_PCER = pcsr | (1 << AT91C_ID_US0);
|
|
|
|
/* Disable and clear USART0 interrupt
|
|
in AIC Interrupt Disable Command Register */
|
|
volatile AT91PS_AIC pAIC = AT91C_BASE_AIC;
|
|
pAIC->AIC_IDCR = (1 << AT91C_ID_US0);
|
|
pAIC->AIC_ICCR = (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_RSTSTA | /* Clear status register */
|
|
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 = 1;
|
|
|
|
/* Receiver Time-out disabled */
|
|
RS485_Interface->US_RTOR = 0;
|
|
|
|
/* 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_baud_rate(void)
|
|
{
|
|
return RS485_Baud;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* DESCRIPTION: Sets the baud rate for the chip USART
|
|
* RETURN: none
|
|
* ALGORITHM: none
|
|
* NOTES: none
|
|
*****************************************************************************/
|
|
bool rs485_baud_rate_set(uint32_t baud)
|
|
{
|
|
bool valid = true;
|
|
|
|
switch (baud) {
|
|
case 9600:
|
|
case 19200:
|
|
case 38400:
|
|
case 57600:
|
|
case 76800:
|
|
case 115200:
|
|
RS485_Baud = baud;
|
|
RS485_Interface->US_BRGR = MCK / 16 / baud;
|
|
/* FIXME: store the baud rate */
|
|
break;
|
|
default:
|
|
valid = false;
|
|
break;
|
|
}
|
|
|
|
return valid;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* DESCRIPTION: Waits on the SilenceTimer for 40 bits.
|
|
* RETURN: none
|
|
* ALGORITHM: none
|
|
* NOTES: none
|
|
*****************************************************************************/
|
|
void RS485_Turnaround_Delay(void)
|
|
{
|
|
uint16_t turnaround_time;
|
|
|
|
/* delay after reception before trasmitting - per MS/TP spec */
|
|
/* wait a minimum 40 bit times since reception */
|
|
/* at least 1 ms for errors: rounding, clock tick */
|
|
turnaround_time = 2 + ((Tturnaround * 1000UL) / RS485_Baud);
|
|
while (Timer_Silence() < turnaround_time) {
|
|
/* do nothing - wait for timer to increment */
|
|
};
|
|
}
|
|
|
|
/****************************************************************************
|
|
* DESCRIPTION: Enable or disable the transmitter
|
|
* RETURN: none
|
|
* ALGORITHM: none
|
|
* NOTES: The Atmel ARM7 has an automatic enable/disable in RS485 mode.
|
|
*****************************************************************************/
|
|
void RS485_Transmitter_Enable(bool enable)
|
|
{
|
|
(void)enable;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* DESCRIPTION: Send some data and wait until it is sent
|
|
* RETURN: none
|
|
* ALGORITHM: none
|
|
* NOTES: none
|
|
*****************************************************************************/
|
|
void RS485_Send_Data(uint8_t *buffer, /* data to send */
|
|
uint16_t nbytes)
|
|
{ /* number of bytes of data */
|
|
/* LED on send */
|
|
volatile AT91PS_PIO pPIO = AT91C_BASE_PIOA;
|
|
/* LED ON */
|
|
pPIO->PIO_CODR = LED1;
|
|
/* send all the bytes */
|
|
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--;
|
|
}
|
|
while (!(RS485_Interface->US_CSR & AT91C_US_TXRDY)) {
|
|
/* do nothing - wait until Tx buffer is empty */
|
|
}
|
|
/* per MSTP spec */
|
|
Timer_Silence_Reset();
|
|
}
|
|
|
|
/****************************************************************************
|
|
* DESCRIPTION: Return true if a framing or overrun error is present
|
|
* RETURN: true if error
|
|
* ALGORITHM: none
|
|
* NOTES: Clears any error flags.
|
|
*****************************************************************************/
|
|
bool RS485_ReceiveError(void)
|
|
{
|
|
bool ReceiveError = false;
|
|
/* LED on send */
|
|
volatile AT91PS_PIO pPIO = AT91C_BASE_PIOA;
|
|
|
|
/* check for data or error */
|
|
if (RS485_Interface->US_CSR & (AT91C_US_OVRE | AT91C_US_FRAME)) {
|
|
/* clear the error flag */
|
|
RS485_Interface->US_CR = AT91C_US_RSTSTA;
|
|
ReceiveError = true;
|
|
/* LED ON */
|
|
pPIO->PIO_CODR = LED2;
|
|
}
|
|
|
|
return ReceiveError;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* DESCRIPTION: Return true if data is available
|
|
* RETURN: true if data is available, with the data in the parameter set
|
|
* ALGORITHM: none
|
|
* NOTES: none
|
|
*****************************************************************************/
|
|
bool RS485_DataAvailable(uint8_t *DataRegister)
|
|
{
|
|
bool DataAvailable = false;
|
|
/* LED on send */
|
|
volatile AT91PS_PIO pPIO = AT91C_BASE_PIOA;
|
|
|
|
if (RS485_Interface->US_CSR & AT91C_US_RXRDY) {
|
|
/* data is available */
|
|
if (DataRegister) {
|
|
*DataRegister = RS485_Interface->US_RHR;
|
|
}
|
|
DataAvailable = true;
|
|
/* LED ON */
|
|
pPIO->PIO_CODR = LED2;
|
|
}
|
|
|
|
return DataAvailable;
|
|
}
|
|
|
|
#ifdef TEST_RS485
|
|
int main(void)
|
|
{
|
|
unsigned i = 0;
|
|
uint8_t DataRegister;
|
|
|
|
rs485_baud_rate_set(38400);
|
|
RS485_Initialize();
|
|
/* receive task */
|
|
for (;;) {
|
|
if (RS485_ReceiveError()) {
|
|
fprintf(stderr, "ERROR ");
|
|
} else if (RS485_DataAvailable(&DataRegister)) {
|
|
fprintf(stderr, "%02X ", DataRegister);
|
|
}
|
|
}
|
|
}
|
|
#endif
|