Serial ISR Callbacks

Typedefs
typedef void(*	serRxIdleCallback_t) (int portnum)
	Callback type for serial port receive-idle detection.
typedef void(*	serTxCompCallback_t) (int portnum, uint32_t bytesSinceLast)
	Callback type for serial port transmit-complete notification.

Functions
serTxCompCallback_t	RegisterTxEmptyCallback (int fd, serTxCompCallback_t pFunc)
	Register a transmit-complete callback.
serRxIdleCallback_t	RegisterSerIdleCallback (int fd, int num_bits, serRxIdleCallback_t pFunc)
	Register a receive-idle callback.

Detailed Description

Callback types and registration functions for serial port interrupt-driven events such as transmit-complete and receive-idle detection.

Note

Only available on MODM7AE70, SBE70LC, SOMRT1061 and MODRT1171.

Typedef Documentation

serRxIdleCallback_t

typedef void(* serRxIdleCallback_t) (int portnum)

#include <serial.h>

Callback type for serial port receive-idle detection.

Called from the serial port ISR when the line has been idle (no data received) for the configured number of bit times.

Parameters

portnum

The UART port number that detected idle

serTxCompCallback_t

typedef void(* serTxCompCallback_t) (int portnum, uint32_t bytesSinceLast)

#include <serial.h>

Callback type for serial port transmit-complete notification.

Called from the serial port ISR when the last character has been transmitted and the shift register is empty.

Parameters

portnum	The UART port number that completed transmission
bytesSinceLast	Number of bytes transmitted since the last callback invocation

Function Documentation

RegisterSerIdleCallback()

serRxIdleCallback_t RegisterSerIdleCallback	(	int	fd,
		int	num_bits,
		serRxIdleCallback_t	pFunc )

#include <serial.h>

Register a receive-idle callback.

Registers a callback function to be invoked from the serial port ISR when the receive line has been idle for the specified number of bit times. This is useful for detecting the end of a message in protocols that use inter-character gaps as frame delimiters (e.g. Modbus RTU). Pass nullptr to unregister a previously registered callback.

Note

Only available on USART ports (SAME70 platforms).

---

Expand for Example Usage

Examples

Example: Detect End-of-Frame Using Idle Timeout

volatile bool frameComplete = false;
 
void MyIdleCallback(int portnum)
{
    frameComplete = true;
}
 
// Register callback with 40-bit idle timeout (~3.5 char times at 8N1)
int fd = SimpleOpenSerial(0, 9600);
RegisterSerIdleCallback(fd, 40, MyIdleCallback);

---

Parameters

fd	The file descriptor of the serial port
num_bits	The number of idle bit times before the callback fires
pFunc	Pointer to the callback function, or nullptr to unregister

Returns

The previously registered callback, or nullptr if none was registered

RegisterTxEmptyCallback()

serTxCompCallback_t RegisterTxEmptyCallback	(	int	fd,
		serTxCompCallback_t	pFunc )

#include <serial.h>

Register a transmit-complete callback.

Registers a callback function to be invoked from the serial port ISR when the last character has been transmitted and the transmitter shift register is empty. Pass nullptr to unregister a previously registered callback.

---

Expand for Example Usage

Examples

Example: Toggle an RS-485 Driver Enable Pin on Transmit Complete

void MyTxDoneCallback(int portnum, uint32_t bytesSinceLast)
{
    // Disable RS-485 driver after last byte has been shifted out
    Pins[RS485_DE_PIN] = 0;
}
 
// In initialization:
int fd = SimpleOpenSerial(0, 115200);
RegisterTxEmptyCallback(fd, MyTxDoneCallback);

---

Parameters

fd	The file descriptor of the serial port
pFunc	Pointer to the callback function, or nullptr to unregister

Returns

The previously registered callback, or nullptr if none was registered