Files
bacnet_stack/ports/pic18f6720/rs485.c
T
Kari Argillander a2f1d6959d Make most of functions const correct (#714)
* Make most of the functions const correct

Used clang-tidy and sonarlint to help find places where const could
pretty easily applied. Also lot of hand work.

This commit does not yet touch handlers and typedefs of those.

* Fix Arduino uno handler_who_is() has extra parenthesis

For some reason there is extra parenthesis. Remove it this is more
likely buildable.

* Bugfix/bacapp: Fix uninitilized array_index

We have changed bacapp_snprintf_value() to be const correct. After that
we got

```
/home/runner/work/bacnet-stack/bacnet-stack/src/bacnet/bacapp.c:3183:27: warning: 4th function call argument is an uninitialized value [core.CallAndMessage]
                ret_val = bacapp_snprintf_weeklyschedule(
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 warning generated.
```

So analyzer could now spot that we do not actually initilize array_index
at all. Fix this by setting array_index to zero. Note that I actually do
not know if zeroing is right thing to do here. I choose zero as if this
has worked before it is most likely that it will work with zero value.

* cmake: Add and ignore Wwrite-strings compiler option

Wwrite-strings helps find places where const correctness is broken.

Example it will warn about these

```C

void func1(char* str);

func("test") /* "test" is const so we should not pass it to func1().

char* func2()
{
  return "test"; /* func2() should return const char*.
}
```

We still need to ignore it as not all are fixed but let's add it already
so we remember that it should be opened at some point.

---------

Co-authored-by: Kari Argillander <kari.argillander@fidelix.com>
2024-08-29 14:08:02 -05:00

328 lines
9.4 KiB
C

/**************************************************************************
*
* Copyright (C) 2005 Steve Karg <skarg@users.sourceforge.net>
*
* 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 <string.h>
#include "hardware.h"
#include "bacnet/datalink/mstp.h"
#include "rs485.h"
#include "bacnet/basic/sys/fifo.h"
/* public port info */
extern volatile struct mstp_port_struct_t MSTP_Port;
/* the baud rate is adjustable */
uint32_t RS485_Baud_Rate = 38400;
/* the FIFO structures for sending and receiving */
FIFO_BUFFER FIFO_Rx;
FIFO_BUFFER FIFO_Tx;
#pragma udata MSTPPortData
/* the buffer for receiving data (size must be a power of 2) */
volatile uint8_t RS485_Rx_Buffer[NEXT_POWER_OF_2(DLMSTP_MPDU_MAX)];
/* the buffer for sending data (size must be a power of 2) */
volatile uint8_t RS485_Tx_Buffer[NEXT_POWER_OF_2(DLMSTP_MPDU_MAX)];
#pragma udata
/****************************************************************************
* DESCRIPTION: Transmits a frame using the UART
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
void RS485_Send_Frame(
volatile struct mstp_port_struct_t *mstp_port, /* port specific data */
const uint8_t *buffer, /* frame to send (up to 501 bytes of data) */
uint16_t nbytes)
{ /* number of bytes of data (up to 501) */
uint16_t i = 0; /* loop counter */
uint8_t turnaround_time;
if (!buffer)
return;
while (!FIFO_Empty(&FIFO_Tx)) {
/* buffer is not empty. Wait for ISR to transmit. */
};
/* wait 40 bit times since reception */
if (RS485_Baud_Rate == 9600)
turnaround_time = 4;
else if (RS485_Baud_Rate == 19200)
turnaround_time = 2;
else
turnaround_time = 2;
while (mstp_port->SilenceTimer < turnaround_time) {
/* The line has not been silent long enough, so wait. */
};
if (FIFO_Add(&FIFO_Tx, buffer, nbytes)) {
/* disable the receiver */
PIE3bits.RC2IE = 0;
RCSTA2bits.CREN = 0;
/* enable the transceiver */
RS485_TX_ENABLE = 1;
RS485_RX_DISABLE = 1;
/* enable the transmitter */
TXSTA2bits.TXEN = 1;
PIE3bits.TX2IE = 1;
/* reset the silence timer per MSTP spec, sort of */
mstp_port->SilenceTimer = 0;
}
return;
}
/****************************************************************************
* DESCRIPTION: Checks for data on the receive UART, and handles errors
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
bool RS485_Check_UART_Data(volatile struct mstp_port_struct_t *mstp_port)
{
/* check for data */
if (!FIFO_Empty(&FIFO_Rx)) {
mstp_port->DataRegister = FIFO_Get(&FIFO_Rx);
mstp_port->DataAvailable = TRUE;
}
return (!FIFO_Empty(&FIFO_Rx));
}
/* *************************************************************************
DESCRIPTION: Receives RS485 data stream
RETURN: none
ALGORITHM: none
NOTES: none
*************************************************************************** */
void RS485_Interrupt_Rx(void)
{
uint8_t data_byte;
if ((RCSTA2bits.FERR) || (RCSTA2bits.OERR)) {
/* Clear the error */
RCSTA2bits.CREN = 0;
RCSTA2bits.CREN = 1;
/* FIXME: flag the MS/TP state machine on buffer overrun */
data_byte = RCREG2;
} else {
data_byte = RCREG2;
FIFO_Put(&FIFO_Rx, data_byte);
}
}
/* *************************************************************************
DESCRIPTION: Transmits a byte using the UART out the RS485 port
RETURN: none
ALGORITHM: none
NOTES: none
*************************************************************************** */
void RS485_Interrupt_Tx(void)
{
if (!FIFO_Empty(&FIFO_Tx)) {
TXREG2 = FIFO_Get(&FIFO_Tx);
} else {
/* wait for the USART to be empty */
while (!TXSTA2bits.TRMT)
;
/* disable this interrupt */
PIE3bits.TX2IE = 0;
/* enable the receiver */
RS485_TX_ENABLE = 0;
RS485_RX_DISABLE = 0;
/* enable the this interrupt */
PIE3bits.RC2IE = 1;
RCSTA2bits.CREN = 1;
}
}
/****************************************************************************
* 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_Rate;
}
/****************************************************************************
* 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 76800:
case 115200:
RS485_Baud_Rate = baud;
break;
default:
valid = false;
break;
}
if (valid) {
/* FIXME: store the baud rate */
/* I2C_Write_Block(
EEPROM_DEVICE_ADDRESS,
(char *)&RS485_Baud_Rate,
sizeof(RS485_Baud_Rate),
EEPROM_MSTP_BAUD_RATE_ADDR); */
}
return valid;
}
/****************************************************************************
* DESCRIPTION: Initializes the RS485 hardware and variables, and starts in
* receive mode.
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
void RS485_Initialize_Port(void)
{
/* Reset USART registers to POR state */
TXSTA2 = 0;
RCSTA2 = 0;
/* configure USART for receiving */
/* since the TX will handle setting up for transmit */
RCSTA2bits.CREN = 1;
/* Interrupt on receipt */
PIE3bits.RC2IE = 1;
/* enable the transmitter, disable its interrupt */
TXSTA2bits.TXEN = 1;
PIE3bits.TX2IE = 0;
/* setup USART Baud Rate Generator */
/* see BAUD RATES FOR ASYNCHRONOUS MODE in Data Book */
/* Fosc=20MHz
BRGH=1 BRGH=0
Rate SPBRG Rate SPBRG
------- ----- ------- -----
9615 129 9469 32
19230 64 19530 15
37878 32 78130 3
56818 21 104200 2
113630 10 312500 0
250000 4
625000 1
1250000 0
*/
switch (RS485_Baud_Rate) {
case 19200:
SPBRG2 = 64;
TXSTA2bits.BRGH = 1;
break;
case 38400:
SPBRG2 = 32;
TXSTA2bits.BRGH = 1;
break;
case 57600:
SPBRG2 = 21;
TXSTA2bits.BRGH = 1;
break;
case 76800:
SPBRG2 = 3;
TXSTA2bits.BRGH = 0;
break;
case 115200:
SPBRG2 = 10;
TXSTA2bits.BRGH = 1;
break;
case 9600:
SPBRG2 = 129;
TXSTA2bits.BRGH = 1;
break;
default:
SPBRG2 = 129;
TXSTA2bits.BRGH = 1;
RS485_Set_Baud_Rate(9600);
break;
}
/* select async mode */
TXSTA2bits.SYNC = 0;
/* enable transmitter */
TXSTA2bits.TXEN = 1;
/* serial port enable */
RCSTA2bits.SPEN = 1;
/* since we are using RS485,
we need to explicitly say
transmit enable or not */
RS485_RX_DISABLE = 0;
RS485_TX_ENABLE = 0;
}
/****************************************************************************
* DESCRIPTION: Disables the RS485 hardware
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
void RS485_Disable_Port(void)
{
RCSTA2 &= 0x4F; /* Disable the receiver */
TXSTA2bits.TXEN = 0; /* and transmitter */
PIE3 &= 0xCF; /* Disable both interrupts */
}
/****************************************************************************
* DESCRIPTION: Reinitializes the port
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
void RS485_Reinit(void)
{
RS485_Set_Baud_Rate(38400);
}
/****************************************************************************
* DESCRIPTION: Initializes the data and the port
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
void RS485_Initialize(void)
{
/* Init the Rs485 buffers */
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 stored baud rate */
/* I2C_Read_Block(
EEPROM_DEVICE_ADDRESS,
(char *)&RS485_Baud_Rate,
sizeof(RS485_Baud_Rate),
EEPROM_MSTP_BAUD_RATE_ADDR); */
RS485_Initialize_Port();
}