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Modified the AT91SAM7S port and the ATmega168 port to use a slimmed down MS/TP state machine and datalink layer. Tested on AT91SAM7S-EK board.

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This commit is contained in:
skarg
2007-09-07 01:34:19 +00:00
parent 4f34f6994b
commit 8fb328ce23
10 changed files with 1285 additions and 359 deletions
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bacnet-stack/ports/at91sam7s/rs485.c
+101 -59
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@@ -32,7 +32,6 @@
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include "mstp.h"
#include "timer.h"
/* This file has been customized for use with UART0
@@ -44,16 +43,17 @@ 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;
}
/* 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
@@ -152,27 +152,51 @@ bool RS485_Set_Baud_Rate(uint32_t baud)
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) */
/****************************************************************************
* DESCRIPTION: Waits on the SilenceTimer for 40 bits.
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
void RS485_Turnaround_Delay(void)
{
uint8_t turnaround_time;
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 = 1 + ((Tturnaround*1000UL)/RS485_Baud);
while (Timer_Silence() < turnaround_time) {
/* do nothing - wait for timer to increment */
};
}
/* delay after reception - per MS/TP spec */
if (mstp_port) {
/* wait a minimum 40 bit times since reception */
/* at least 1 ms for errors: rounding, clock tick */
turnaround_time = 1 + ((Tturnaround*1000)/RS485_Baud);
while (mstp_port->SilenceTimer() < turnaround_time) {
/* do nothing - wait for timer to increment */
};
}
/* toggle LED on send */
/****************************************************************************
* 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 */
@@ -180,60 +204,78 @@ void RS485_Send_Frame(
RS485_Interface->US_THR = *buffer;
buffer++;
nbytes--;
/* per MSTP spec */
if (mstp_port) {
mstp_port->SilenceTimerReset();
}
}
while (!(RS485_Interface->US_CSR & AT91C_US_TXRDY)) {
/* do nothing - wait until Tx buffer is empty */
}
return;
/* per MSTP spec */
Timer_Silence_Reset();
}
/* called by timer, interrupt(?) or other thread */
void RS485_Check_UART_Data(struct mstp_port_struct_t *mstp_port)
/****************************************************************************
* 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;
if (mstp_port->ReceiveError == true) {
/* wait for state machine to clear this */
} else if (mstp_port->DataAvailable == false) {
/* 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;
mstp_port->ReceiveError = true;
/* LED ON */
pPIO->PIO_CODR = LED2;
} else if ( RS485_Interface->US_CSR & AT91C_US_RXRDY) {
/* data is available */
mstp_port->DataRegister = RS485_Interface->US_RHR;
mstp_port->DataAvailable = true;
/* LED ON */
pPIO->PIO_CODR = LED2;
}
/* 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 */
*DataRegister = RS485_Interface->US_RHR;
DataAvailable = true;
/* LED ON */
pPIO->PIO_CODR = LED2;
}
return DataAvailable;
}
#ifdef TEST_RS485
static struct mstp_port_struct_t MSTP_Port;
int main(void)
{
unsigned i = 0;
uint8_t DataRegister;
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;
if (RS485_DataAvailable(&DataRegister)) {
fprintf(stderr,"%02X ",DataRegister);
} else if (RS485_ReceiveError()) {
fprintf(stderr,"ERROR ");
}
}
}
#endif /* TEST_ABORT */
#endif