openmrn_arduino::Esp32HardwareTwai Class Reference

ESP32 Hardware TWAI (CAN) driver interface. More...

#include <Esp32HardwareTwai.hxx>

Inheritance diagram for openmrn_arduino::Esp32HardwareTwai:

Public Member Functions
	Esp32HardwareTwai (int rx, int tx, bool report=true, size_t rx_buffer_size=config_can_rx_buffer_size(), size_t tx_buffer_size=config_can_tx_buffer_size(), const char *path="/dev/twai", int clock_out=GPIO_NUM_NC, int bus_status=GPIO_NUM_NC, uint32_t isr_preferred_core=DEFAULT_ISR_CORE)
	~Esp32HardwareTwai ()
	Destructor.
void	hw_init ()
	Initializes the TWAI hardware and VFS adapter.
void	get_driver_stats (esp32_twai_stats_t *stats)
	Retrieves the current driver statistics.

Private Member Functions
	Esp32HardwareTwai ()
	Default constructor.
	DISALLOW_COPY_AND_ASSIGN (Esp32HardwareTwai)

Private Attributes
const int	rxPin_
	GPIO pin connected to the external transceiver RX pin.
const int	txPin_
	GPIO pin connected to the external transceiver TX pin.
const int	extClockPin_
	GPIO pin that generates an external clock signal.
const int	busStatusPin_
	GPIO pin connected to an external bus status indicator.
const uint32_t	preferredIsrCore_
	Core which the TWAI ISR should be bound to.
const char *	vfsPath_
	VFS Mount point.

Static Private Attributes
static constexpr uint32_t	DEFAULT_ISR_CORE = PRO_CPU_NUM
	Default core for running the TWAI ISR.

Additional Inherited Members
Static Public Member Functions inherited from Singleton< Esp32HardwareTwai >
static Esp32HardwareTwai *	instance ()
static bool	exists ()

Detailed Description

ESP32 Hardware TWAI (CAN) driver interface.

The ESP32 has a hardware TWAI controller that requires an external CAN transceiver connected via two GPIO pins (RX and TX). SPI connected CAN transceivers are not supported by this interface.

Example of usage (async API):

Esp32HardwareTwai twai;
void setup() {
  ...
  twai.hw_init();
  openmrn.begin();
  openmrn.add_can_port_async("/dev/twai/twai0");
  ...
}

Example of usage (select API):

Esp32HardwareTwai twai;
void setup() {
  ...
  twai.hw_init();
  openmrn.begin();
  openmrn.add_can_port_select("/dev/twai/twai0");
  openmrn.start_executor_thread();
  ...
}

NOTE: For the select API it is necessary to start the executor thread in the setup() method.

NOTE: The select API is not be usable without CONFIG_VFS_SUPPORT_SELECT being enabled in sdkconfig, this option is disabled automatically when CONFIG_LWIP_USE_ONLY_LWIP_SELECT is enabled. CONFIG_VFS_SUPPORT_SELECT is enabled by default in arduino-esp32.

Definition at line 128 of file Esp32HardwareTwai.hxx.

Member Function Documentation

get_driver_stats()

void openmrn_arduino::Esp32HardwareTwai::get_driver_stats

(

esp32_twai_stats_t *

stats

)

Retrieves the current driver statistics.

Parameters

stats

esp32_twai_stats_t buffer to be filled with the current statistics.

hw_init()

void openmrn_arduino::Esp32HardwareTwai::hw_init

(

)

Initializes the TWAI hardware and VFS adapter.

NOTE: This must be called prior to adding the TWAI driver to the SimpleCanStack.

Member Data Documentation

busStatusPin_

const int openmrn_arduino::Esp32HardwareTwai::busStatusPin_

private

GPIO pin connected to an external bus status indicator.

Definition at line 195 of file Esp32HardwareTwai.hxx.

DEFAULT_ISR_CORE

constexpr uint32_t openmrn_arduino::Esp32HardwareTwai::DEFAULT_ISR_CORE = PRO_CPU_NUM

staticconstexprprivate

Default core for running the TWAI ISR.

Definition at line 205 of file Esp32HardwareTwai.hxx.

extClockPin_

const int openmrn_arduino::Esp32HardwareTwai::extClockPin_

private

GPIO pin that generates an external clock signal.

Definition at line 192 of file Esp32HardwareTwai.hxx.

preferredIsrCore_

const uint32_t openmrn_arduino::Esp32HardwareTwai::preferredIsrCore_

private

Core which the TWAI ISR should be bound to.

Definition at line 198 of file Esp32HardwareTwai.hxx.

rxPin_

const int openmrn_arduino::Esp32HardwareTwai::rxPin_

private

GPIO pin connected to the external transceiver RX pin.

Definition at line 186 of file Esp32HardwareTwai.hxx.

txPin_

const int openmrn_arduino::Esp32HardwareTwai::txPin_

private

GPIO pin connected to the external transceiver TX pin.

Definition at line 189 of file Esp32HardwareTwai.hxx.

vfsPath_

const char* openmrn_arduino::Esp32HardwareTwai::vfsPath_

private

VFS Mount point.

Definition at line 209 of file Esp32HardwareTwai.hxx.

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The documentation for this class was generated from the following file:

• Esp32HardwareTwai.hxx