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Modified the PIC port MS/TP RS-485 handling to use an interrupt safe FIFO library (untested).

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This commit is contained in:
skarg
2008-11-28 13:37:42 +00:00
parent 858adac724
commit 63f3f77552
5 changed files with 90 additions and 98 deletions
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bacnet-stack/ports/pic18f6720/rs485.c
+36 -75
View File
@@ -33,6 +33,7 @@
#include "hardware.h"
#include "mstp.h"
#include "rs485.h"
#include "fifo.h"
/* public port info */
extern volatile struct mstp_port_struct_t MSTP_Port;
@@ -40,16 +41,14 @@ extern volatile struct mstp_port_struct_t MSTP_Port;
/* the baud rate is adjustable */
uint32_t RS485_Baud_Rate = 38400;
/* the ISR and other use this for status and control */
COMSTAT RS485_Comstat;
/*#pragma udata MSTPPortData
*/
/* the buffer for receiving characters */
volatile uint8_t RS485_Rx_Buffer[MAX_MPDU];
/* UART transmission buffer and index */
volatile uint8_t RS485_Tx_Buffer[MAX_MPDU];
/* the buffer for receiving data (size must be a power of 2) */
volatile uint8_t RS485_Rx_Buffer[128];
FIFO_BUFFER FIFO_Rx;
/* the buffer for sending data (size must be a power of 2) */
volatile uint8_t RS485_Tx_Buffer[128];
FIFO_BUFFER FIFO_Tx;
/****************************************************************************
* DESCRIPTION: Transmits a frame using the UART
@@ -68,12 +67,8 @@ void RS485_Send_Frame(
if (!buffer)
return;
/* bounds check */
if (nbytes >= sizeof(RS485_Tx_Buffer))
return;
/* buffer is full. Wait for ISR to transmit. */
while (RS485_Comstat.Tx_Bytes) {
while (!Empty(&FIFO_Tx)) {
/* buffer is not empty. Wait for ISR to transmit. */
};
/* wait 40 bit times since reception */
@@ -85,18 +80,10 @@ void RS485_Send_Frame(
turnaround_time = 1;
while (mstp_port->SilenceTimer < turnaround_time) {
/* The line has not been silent long enough, so wait. */
};
RS485_Comstat.TxHead = 0;
memcpy((void *) &RS485_Tx_Buffer[0], (void *) buffer, nbytes);
#if 0
for (i = 0; i < nbytes; i++) {
/* put the data into the buffer */
RS485_Tx_Buffer[i] = *buffer;
buffer++;
}
#endif
RS485_Comstat.Tx_Bytes = nbytes;
FIFO_Add(&FIFO_Tx, buffer, nbytes);
/* disable the receiver */
PIE3bits.RC2IE = 0;
RCSTA2bits.CREN = 0;
@@ -106,7 +93,7 @@ void RS485_Send_Frame(
/* enable the transmitter */
TXSTA2bits.TXEN = 1;
PIE3bits.TX2IE = 1;
/* per MSTP spec, sort of */
/* reset the silence timer per MSTP spec, sort of */
mstp_port->SilenceTimer = 0;
return;
@@ -118,29 +105,16 @@ void RS485_Send_Frame(
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
uint8_t RS485_Check_UART_Data(
bool RS485_Check_UART_Data(
volatile struct mstp_port_struct_t * mstp_port)
{
/* check for data */
if (RS485_Comstat.Rx_Bytes) {
mstp_port->DataRegister = RS485_Rx_Buffer[RS485_Comstat.RxTail];
if (RS485_Comstat.RxTail >= (sizeof(RS485_Rx_Buffer) - 1))
RS485_Comstat.RxTail = 0;
else
RS485_Comstat.RxTail++;
/* FIXME: disable interrupts around Rx_Bytes */
RS485_Comstat.Rx_Bytes--;
/* errors? let the state machine know */
if (RS485_Comstat.Rx_Bufferoverrun) {
RS485_Comstat.Rx_Bufferoverrun = FALSE;
mstp_port->ReceiveError = TRUE;
}
/* We read a good byte */
else
mstp_port->DataAvailable = TRUE;
if (!FIFO_Empty(&FIFO_Rx)) {
mstp_port->DataRegister = FIFO_Get(&FIFO_Rx);
mstp_port->DataAvailable = TRUE;
}
return RS485_Comstat.Rx_Bytes;
return (!FIFO_Empty(&FIFO_Rx));
}
/* *************************************************************************
@@ -155,25 +129,17 @@ uint8_t RS485_Check_UART_Data(
void RS485_Interrupt_Rx(
void)
{
char dummy;
uint8_t data_byte;
if ((RCSTA2bits.FERR) || (RCSTA2bits.OERR)) {
/* Clear the error */
RCSTA2bits.CREN = 0;
RCSTA2bits.CREN = 1;
RS485_Comstat.Rx_Bufferoverrun = TRUE;
dummy = RCREG2;
} else if (RS485_Comstat.Rx_Bytes < sizeof(RS485_Rx_Buffer)) {
RS485_Rx_Buffer[RS485_Comstat.RxHead] = RCREG2;
if (RS485_Comstat.RxHead >= (sizeof(RS485_Rx_Buffer) - 1))
RS485_Comstat.RxHead = 0;
else
RS485_Comstat.RxHead++;
RS485_Comstat.Rx_Bytes++;
/* FIXME: flag the MS/TP state machine on buffer overrun */
data_byte = RCREG2;
} else {
RS485_Comstat.Rx_Bufferoverrun = TRUE;
dummy = RCREG2;
(void) dummy;
data_byte = RCREG2;
FIFO_Put(&FIFO_Rx, data_byte);
}
}
@@ -189,13 +155,8 @@ void RS485_Interrupt_Rx(
void RS485_Interrupt_Tx(
void)
{
if (RS485_Comstat.Tx_Bytes) {
/* Get the data byte */
TXREG2 = RS485_Tx_Buffer[RS485_Comstat.TxHead];
/* point to the next byte */
RS485_Comstat.TxHead++;
/* reduce the buffer size */
RS485_Comstat.Tx_Bytes--;
if (!FIFO_Empty(&FIFO_Tx)) {
TXREG2 = FIFO_Get(&FIFO_Tx);
} else {
/* wait for the USART to be empty */
while (!TXSTA2bits.TRMT);
@@ -204,8 +165,7 @@ void RS485_Interrupt_Tx(
/* enable the receiver */
RS485_TX_ENABLE = 0;
RS485_RX_DISABLE = 0;
/* FIXME: might not be necessary
*/
/* enable the this interrupt */
PIE3bits.RC2IE = 1;
RCSTA2bits.CREN = 1;
}
@@ -251,7 +211,7 @@ bool RS485_Set_Baud_Rate(
if (valid) {
/* FIXME: store the baud rate */
/* I2C_Write_Block(
EEPROM_DEVICE_ADDRESS,
EEPROM_DEVICE_ADDRESS,
(char *)&RS485_Baud_Rate,
sizeof(RS485_Baud_Rate),
EEPROM_MSTP_BAUD_RATE_ADDR); */
@@ -355,6 +315,12 @@ void RS485_Disable_Port(
PIE3 &= 0xCF; /* Disable both interrupts */
}
/****************************************************************************
* DESCRIPTION: Reinitializes the port
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
void RS485_Reinit(
void)
{
@@ -371,17 +337,12 @@ void RS485_Initialize(
void)
{
/* Init the Rs485 buffers */
RS485_Comstat.RxHead = 0;
RS485_Comstat.RxTail = 0;
RS485_Comstat.Rx_Bytes = 0;
RS485_Comstat.Rx_Bufferoverrun = FALSE;
RS485_Comstat.TxHead = 0;
RS485_Comstat.TxTail = 0;
RS485_Comstat.Tx_Bytes = 0;
FIFO_Init(&FIFO_Rx, RS485_Rx_Buffer, sizeof(RS485_Rx_Buffer));
FIFO_Init(&FIFO_Tx, RS485_Tx_Buffer, sizeof(RS485_Tx_Buffer));
/* FIXME: read the data from storage */
/* FIXME: read the stored baud rate */
/* I2C_Read_Block(
EEPROM_DEVICE_ADDRESS,
EEPROM_DEVICE_ADDRESS,
(char *)&RS485_Baud_Rate,
sizeof(RS485_Baud_Rate),
EEPROM_MSTP_BAUD_RATE_ADDR); */