Parallel IO

[中文]

Introduction

The Parallel IO peripheral is a general purpose parallel interface that can be used to connect to external devices such as LED matrix, LCD display, Printer and Camera. The peripheral has independent TX and RX units. Each unit can have up to 8 or 16 data signals plus 1 or 2 clock signals. 1

The TX and RX driver of Parallel IO peripheral are designed separately, you can include driver/parlio_tx.h or driver/parlio_rx.h to use any of them.

Application Examples

  • peripherals/parlio/parlio_rx/logic_analyzer demonstrates how to implement a logic analyzer using the Parallel IO RX peripheral, which can sample data on multiple GPIOs in parallel at a high rate, and provides options to probe either internal or external signals and output the raw data via flash or TCP stream.

  • peripherals/parlio/parlio_tx/simple_rgb_led_matrix demonstrates how to use the Parallel IO TX unit of ESP32-H2 to drive a RGB LED Matrix board with a HUB75 interface, using the LVGL library to display simple UI elements.

API Reference

Header File

  • components/esp_driver_parlio/include/driver/parlio_tx.h

  • This header file can be included with:

    #include "driver/parlio_tx.h"

  • This header file is a part of the API provided by the esp_driver_parlio component. To declare that your component depends on esp_driver_parlio, add the following to your CMakeLists.txt:

    REQUIRES esp_driver_parlio

    or

    PRIV_REQUIRES esp_driver_parlio

Functions

esp_err_t parlio_new_tx_unit(const parlio_tx_unit_config_t *config, parlio_tx_unit_handle_t *ret_unit)

Create a Parallel IO TX unit.

Parameters

  • config -- [in] Parallel IO TX unit configuration

  • ret_unit -- [out] Returned Parallel IO TX unit handle

Returns

  • ESP_OK: Create Parallel IO TX unit successfully

  • ESP_ERR_INVALID_ARG: Create Parallel IO TX unit failed because of invalid argument

  • ESP_ERR_NO_MEM: Create Parallel IO TX unit failed because of out of memory

  • ESP_ERR_NOT_FOUND: Create Parallel IO TX unit failed because all TX units are used up and no more free one

  • ESP_ERR_NOT_SUPPORTED: Create Parallel IO TX unit failed because some feature is not supported by hardware, e.g. clock gating

  • ESP_FAIL: Create Parallel IO TX unit failed because of other error

esp_err_t parlio_del_tx_unit(parlio_tx_unit_handle_t unit)

Delete a Parallel IO TX unit.

Parameters

unit -- [in] Parallel IO TX unit that created by parlio_new_tx_unit

Returns

  • ESP_OK: Delete Parallel IO TX unit successfully

  • ESP_ERR_INVALID_ARG: Delete Parallel IO TX unit failed because of invalid argument

  • ESP_ERR_INVALID_STATE: Delete Parallel IO TX unit failed because it is still in working

  • ESP_FAIL: Delete Parallel IO TX unit failed because of other error

esp_err_t parlio_tx_unit_enable(parlio_tx_unit_handle_t unit)

Enable the Parallel IO TX unit.

Note

This function will transit the driver state from init to enable

Note

This function will acquire a PM lock that might be installed during channel allocation

Note

If there're transaction pending in the queue, this function will pick up the first one and start the transfer

Parameters

unit -- [in] Parallel IO TX unit that created by parlio_new_tx_unit

Returns

  • ESP_OK: Enable Parallel IO TX unit successfully

  • ESP_ERR_INVALID_ARG: Enable Parallel IO TX unit failed because of invalid argument

  • ESP_ERR_INVALID_STATE: Enable Parallel IO TX unit failed because it is already enabled

  • ESP_FAIL: Enable Parallel IO TX unit failed because of other error

esp_err_t parlio_tx_unit_disable(parlio_tx_unit_handle_t unit)

Disable the Parallel IO TX unit.

Note

This function will transit the driver state from enable to init

Note

This function will release the PM lock that might be installed during channel allocation

Note

If one transaction is undergoing, this function will terminate it immediately

Parameters

unit -- [in] Parallel IO TX unit that created by parlio_new_tx_unit

Returns

  • ESP_OK: Disable Parallel IO TX unit successfully

  • ESP_ERR_INVALID_ARG: Disable Parallel IO TX unit failed because of invalid argument

  • ESP_ERR_INVALID_STATE: Disable Parallel IO TX unit failed because it's not enabled yet

  • ESP_FAIL: Disable Parallel IO TX unit failed because of other error

esp_err_t parlio_tx_unit_register_event_callbacks(parlio_tx_unit_handle_t tx_unit, const parlio_tx_event_callbacks_t *cbs, void *user_data)

Set event callbacks for Parallel IO TX unit.

Note

User can deregister a previously registered callback by calling this function and setting the callback member in the cbs structure to NULL.

Note

When CONFIG_PARLIO_ISR_IRAM_SAFE is enabled, the callback itself and functions called by it should be placed in IRAM. The variables used in the function should be in the SRAM as well. The user_data should also reside in SRAM.

Parameters

  • tx_unit -- [in] Parallel IO TX unit that created by parlio_new_tx_unit

  • cbs -- [in] Group of callback functions

  • user_data -- [in] User data, which will be passed to callback functions directly

Returns

  • ESP_OK: Set event callbacks successfully

  • ESP_ERR_INVALID_ARG: Set event callbacks failed because of invalid argument

  • ESP_FAIL: Set event callbacks failed because of other error

esp_err_t parlio_tx_unit_transmit(parlio_tx_unit_handle_t tx_unit, const void *payload, size_t payload_bits, const parlio_transmit_config_t *config)

Transmit data on by Parallel IO TX unit.

Note

After the function returns, it doesn't mean the transaction is finished. This function only constructs a transaction structure and push into a queue.

Parameters

  • tx_unit -- [in] Parallel IO TX unit that created by parlio_new_tx_unit

  • payload -- [in] Pointer to the data to be transmitted

  • payload_bits -- [in] Length of the data to be transmitted, in bits

  • config -- [in] Transmit configuration

Returns

  • ESP_OK: Transmit data successfully

  • ESP_ERR_INVALID_ARG: Transmit data failed because of invalid argument

  • ESP_ERR_INVALID_STATE: Transmit data failed because the Parallel IO TX unit is not enabled

  • ESP_FAIL: Transmit data failed because of other error

esp_err_t parlio_tx_unit_wait_all_done(parlio_tx_unit_handle_t tx_unit, int timeout_ms)

Wait for all pending TX transactions done.

Parameters

  • tx_unit -- [in] Parallel IO TX unit that created by parlio_new_tx_unit

  • timeout_ms -- [in] Timeout in milliseconds, -1 means to wait forever

Returns

  • ESP_OK: All pending TX transactions is finished and recycled

  • ESP_ERR_INVALID_ARG: Wait for all pending TX transactions done failed because of invalid argument

  • ESP_ERR_TIMEOUT: Wait for all pending TX transactions done timeout

  • ESP_FAIL: Wait for all pending TX transactions done failed because of other error

Structures

struct parlio_tx_unit_config_t

Parallel IO TX unit configuration.

Public Members

parlio_clock_source_t clk_src

Parallel IO internal clock source

gpio_num_t clk_in_gpio_num

If the clock source is input from external, set the corresponding GPIO number. Otherwise, set to -1 and the driver will use the internal clk_src as clock source. This option has higher priority than clk_src

uint32_t input_clk_src_freq_hz

Frequency of the input clock source, valid only if clk_in_gpio_num is not -1

uint32_t output_clk_freq_hz

Frequency of the output clock. It's divided from either internal clk_src or external clock source

size_t data_width

Parallel IO data width, can set to 1/2/4/8/..., but can't bigger than PARLIO_TX_UNIT_MAX_DATA_WIDTH

gpio_num_t data_gpio_nums[PARLIO_TX_UNIT_MAX_DATA_WIDTH]

Parallel IO data GPIO numbers, if any GPIO is not used, you can set it to -1

gpio_num_t clk_out_gpio_num

GPIO number of the output clock signal, the clock is synced with TX data

gpio_num_t valid_gpio_num

GPIO number of the valid signal, which stays high when transferring data. Note that, the valid signal will always occupy the MSB data bit

size_t trans_queue_depth

Depth of internal transaction queue

size_t max_transfer_size

Maximum transfer size in one transaction, in bytes. This decides the number of DMA nodes will be used for each transaction

size_t dma_burst_size

DMA burst size, in bytes

parlio_sample_edge_t sample_edge

Parallel IO sample edge

parlio_bit_pack_order_t bit_pack_order

Set the order of packing the bits into bytes (only works when data_width < 8)

uint32_t clk_gate_en

Enable TX clock gating, the output clock will be controlled by the MSB bit of the data bus, i.e. by data_gpio_nums[PARLIO_TX_UNIT_MAX_DATA_WIDTH-1]. High level to enable the clock output, low to disable

uint32_t io_loop_back

For debug/test, the signal output from the GPIO will be fed to the input path as well

uint32_t allow_pd

Set to allow power down. When this flag set, the driver will backup/restore the PARLIO registers before/after entering/exist sleep mode. By this approach, the system can power off PARLIO's power domain. This can save power, but at the expense of more RAM being consumed.

struct parlio_tx_unit_config_t::[anonymous] flags

Extra configuration flags

struct parlio_tx_done_event_data_t

Type of Parallel IO TX done event data.

struct parlio_tx_event_callbacks_t

Group of Parallel IO TX callbacks.

Note

The callbacks are all running under ISR environment

Note

When CONFIG_PARLIO_ISR_IRAM_SAFE is enabled, the callback itself and functions called by it should be placed in IRAM. The variables used in the function should be in the SRAM as well.

Public Members

parlio_tx_done_callback_t on_trans_done

Event callback, invoked when one transmission is finished

struct parlio_transmit_config_t

Parallel IO transmit configuration.

Public Members

uint32_t idle_value

The value on the data line when the parallel IO is in idle state

uint32_t queue_nonblocking

If set, when the transaction queue is full, driver will not block the thread but return directly

struct parlio_transmit_config_t::[anonymous] flags

Transmit specific config flags

Type Definitions

typedef bool (*parlio_tx_done_callback_t)(parlio_tx_unit_handle_t tx_unit, const parlio_tx_done_event_data_t *edata, void *user_ctx)

Prototype of parlio tx event callback.

Param tx_unit

[in] Parallel IO TX unit that created by parlio_new_tx_unit

Param edata

[in] Point to Parallel IO TX event data. The lifecycle of this pointer memory is inside this function, user should copy it into static memory if used outside this function.

Param user_ctx

[in] User registered context, passed from parlio_tx_unit_register_event_callbacks

Return

Whether a high priority task has been waken up by this callback function

Header File

  • components/esp_driver_parlio/include/driver/parlio_rx.h

  • This header file can be included with:

    #include "driver/parlio_rx.h"

  • This header file is a part of the API provided by the esp_driver_parlio component. To declare that your component depends on esp_driver_parlio, add the following to your CMakeLists.txt:

    REQUIRES esp_driver_parlio

    or

    PRIV_REQUIRES esp_driver_parlio

Functions

esp_err_t parlio_new_rx_unit(const parlio_rx_unit_config_t *config, parlio_rx_unit_handle_t *ret_unit)

Create a Parallel IO RX unit.

Parameters

  • config -- [in] Parallel IO RX unit configuration

  • ret_unit -- [out] Returned Parallel IO RX unit handle

Returns

  • ESP_ERR_INVALID_ARG Invalid arguments in the parameter list or the rx unit configuration

  • ESP_ERR_NOT_FOUND No available rx unit found

  • ESP_ERR_NO_MEM No enough memory for the rx unit resources

  • ESP_OK Success to allocate the rx unit

esp_err_t parlio_del_rx_unit(parlio_rx_unit_handle_t rx_unit)

Delete a Parallel IO RX unit.

Parameters

rx_unit -- [in] Parallel IO RX unit handle that created by parlio_new_rx_unit

Returns

  • ESP_ERR_INVALID_ARG rx_unit is NULL

  • ESP_ERR_INVALID_STATE The rx unit is enabled, can't delete an enabled rx unit

  • ESP_OK Success to delete the rx unit

esp_err_t parlio_new_rx_level_delimiter(const parlio_rx_level_delimiter_config_t *config, parlio_rx_delimiter_handle_t *ret_delimiter)

Create a level delimiter.

Note

This function only allocate the software resources, the hardware configurations will lazy installed while the transaction that using this delimiter start processing

Note

The enable signal must be aligned with the valid data.

Note

There're at most SOC_PARLIO_RX_UNIT_MAX_DATA_WIDTH - 1 IO pins left for RXD

Parameters

  • config -- [in] Level delimiter configuration

  • ret_delimiter -- [out] Returned delimiter handle

Returns

  • ESP_ERR_INVALID_ARG Invalid arguments in the parameter list or the level delimiter configuration

  • ESP_ERR_NO_MEM No enough memory for the level delimiter resources

  • ESP_OK Success to allocate the level delimiter

esp_err_t parlio_new_rx_pulse_delimiter(const parlio_rx_pulse_delimiter_config_t *config, parlio_rx_delimiter_handle_t *ret_delimiter)

Create a pulse delimiter.

Note

This function only allocate the software resources, the hardware configurations will lazy installed while the transaction that using this delimiter start processing

Note

There're at most SOC_PARLIO_RX_UNIT_MAX_DATA_WIDTH - 1 IO pins left for RXD

Parameters

  • config -- [in] Pulse delimiter configuration

  • ret_delimiter -- [out] Returned delimiter handle

Returns

  • ESP_ERR_INVALID_ARG Invalid arguments in the parameter list or the pulse delimiter configuration

  • ESP_ERR_NO_MEM No enough memory for the pulse delimiter resources

  • ESP_OK Success to allocate the pulse delimiter

esp_err_t parlio_new_rx_soft_delimiter(const parlio_rx_soft_delimiter_config_t *config, parlio_rx_delimiter_handle_t *ret_delimiter)

Create a pulse delimiter.

Note

This function only allocate the software resources, the hardware configurations will lazy installed while the transaction that using this delimiter start processing

Parameters

  • config -- [in] Soft delimiter configuration

  • ret_delimiter -- [out] Returned delimiter handle

Returns

  • ESP_ERR_INVALID_ARG Invalid arguments in the parameter list or the soft delimiter configuration

  • ESP_ERR_NO_MEM No enough memory for the soft delimiter resources

  • ESP_OK Success to allocate the soft delimiter

esp_err_t parlio_rx_soft_delimiter_start_stop(parlio_rx_unit_handle_t rx_unit, parlio_rx_delimiter_handle_t delimiter, bool start_stop)

Start/stop the soft delimiter.

Note

Soft delimiter need to start or stop manually because it has no validating/enabling signal to indicate the data has started or stopped

Parameters

  • rx_unit -- [in] Parallel IO RX unit handle that created by parlio_new_rx_unit

  • delimiter -- [in] Delimiter handle

  • start_stop -- [in] Set true to start, set false to stop

Returns

  • ESP_ERR_INVALID_ARG Invalid arguments in the parameter list or not soft delimiter

  • ESP_ERR_INVALID_STATE The rx unit not enabled

  • ESP_OK Success to start or stop the soft delimiter

esp_err_t parlio_del_rx_delimiter(parlio_rx_delimiter_handle_t delimiter)

Delete the delimiter.

Note

To delete the delimiter safely, please delete it after disable all the RX units

Parameters

delimiter -- [in] Delimiter handle

Returns

  • ESP_ERR_INVALID_ARG The input delimiter is NULL

  • ESP_ERR_INVALID_STATE The delimiter is on receiving

  • ESP_OK Success to delete the delimiter

esp_err_t parlio_rx_unit_enable(parlio_rx_unit_handle_t rx_unit, bool reset_queue)

Enable the Parallel IO RX unit.

Parameters

  • rx_unit -- [in] Parallel IO RX unit handle that created by parlio_new_rx_unit

  • reset_queue -- [in] Whether to reset the receiving queue. If set to false, the legacy receive transactions in the queue are still available, If set to true, the legacy receive transactions in the queue are dropped.

Returns

  • ESP_ERR_INVALID_ARG The input rx_unit is NULL

  • ESP_ERR_INVALID_STATE The rx unit has been enabled

  • ESP_OK Success to enable the rx unit

esp_err_t parlio_rx_unit_disable(parlio_rx_unit_handle_t rx_unit)

Disable the Parallel IO RX unit.

Parameters

rx_unit -- [in] Parallel IO RX unit handle that created by parlio_new_rx_unit

Returns

  • ESP_ERR_INVALID_ARG The input rx_unit is NULL

  • ESP_ERR_INVALID_STATE The rx unit has been disabled

  • ESP_OK Success to disable the rx unit

esp_err_t parlio_rx_unit_receive(parlio_rx_unit_handle_t rx_unit, void *payload, size_t payload_size, const parlio_receive_config_t *recv_cfg)

Receive data by Parallel IO RX unit.

Note

This is a non-blocking and asynchronous function. To block or realize synchronous receive, please call parlio_rx_unit_wait_all_done after this function

Note

The receive transaction will start immediately when there is not other transaction on receiving, Otherwise it will be sent to the transaction queue to wait for the bus.

Parameters

  • rx_unit -- [in] Parallel IO RX unit handle that created by parlio_new_rx_unit

  • payload -- [in] The payload buffer pointer

  • payload_size -- [in] The size of the payload buffer, in bytes.

  • recv_cfg -- [in] The configuration of this receive transaction

Returns

  • ESP_ERR_INVALID_ARG Invalid arguments in the parameter list or the receive configuration

  • ESP_ERR_NO_MEM No memory for the internal DMA buffer (only when parlio_receive_config_t::indirect_mount enabled)

  • ESP_ERR_INVALID_STATE Transaction queue is full, failed to queue the current transaction. Or the internal buffer is under using by an infinite transaction, can't allocate a new one

  • ESP_OK Success to queue the current receiving transaction

esp_err_t parlio_rx_unit_wait_all_done(parlio_rx_unit_handle_t rx_unit, int timeout_ms)

Wait for all pending RX transactions done.

Note

This function will block until all receiving transactions done or timeout. When timeout occurs, either the timeout limitation too short for all transactions done, or the peripheral got stuck and no more interrupts trigger (e.g., external clock stopped).

Parameters

  • rx_unit -- [in] Parallel IO RX unit handle that created by parlio_new_rx_unit

  • timeout_ms -- [in] Timeout in milliseconds, -1 means to wait forever (software timeout)

Returns

  • ESP_ERR_INVALID_ARG The input rx_unit is NULL

  • ESP_ERR_TIMEOUT Wait for all transactions done timeout

  • ESP_OK All transaction done

esp_err_t parlio_rx_unit_register_event_callbacks(parlio_rx_unit_handle_t rx_unit, const parlio_rx_event_callbacks_t *cbs, void *user_data)

Register event callbacks for Parallel IO RX unit.

Parameters

  • rx_unit -- [in] Parallel IO RX unit handle that created by parlio_new_rx_unit

  • cbs -- [in] Callback group, set callback to NULL to deregister the corresponding callback (callback group pointer shouldn't be NULL)

  • user_data -- [in] User specified data that will be transported to the callbacks

Returns

  • ESP_ERR_INVALID_ARG The input rx_unit is NULL

  • ESP_ERR_INVALID_STATE The rx unit has been enabled, callback should be registered before enabling the unit

  • ESP_OK Success to register the callbacks

Structures

struct parlio_rx_unit_config_t

Parallel IO RX unit configuration.

Public Members

size_t trans_queue_depth

Depth of internal transaction queue

size_t max_recv_size

Maximum receive size in one transaction, in bytes. This decides the number of DMA nodes will be used for each transaction

size_t data_width

Parallel IO data width, can set to 1/2/4/8/..., but can't be greater than PARLIO_RX_UNIT_MAX_DATA_WIDTH

parlio_clock_source_t clk_src

Parallel IO clock source

uint32_t ext_clk_freq_hz

The external source clock frequency. Only be valid when select PARLIO_CLK_SRC_EXTERNAL as clock source

uint32_t exp_clk_freq_hz

The expected sample/bit clock frequency, which is divided from the internal or external clock regarding the clock source

gpio_num_t clk_in_gpio_num

The the external clock input pin. Only be valid when select PARLIO_CLK_SRC_EXTERNAL as clock source. Set to -1 if not needed

gpio_num_t clk_out_gpio_num

The sample/bit clock output pin. Set to -1 if not needed

gpio_num_t valid_gpio_num

GPIO number of the valid signal. The signal on this pin is used to indicate whether the data on the data lines are valid. Only takes effect when using level or pulse delimiter, set to -1 if only use the soft delimiter

gpio_num_t data_gpio_nums[PARLIO_RX_UNIT_MAX_DATA_WIDTH]

Parallel IO data GPIO numbers, set to -1 if it's not used, The driver will take [0 .. (data_width - 1)] as the data pins

uint32_t free_clk

Whether the input external clock is a free-running clock. A free-running clock will always keep running (e.g. I2S bclk), a non-free-running clock will start when there are data transporting and stop when the bus idle (e.g. SPI). This flag only takes effect when select PARLIO_CLK_SRC_EXTERNAL as clock source

uint32_t clk_gate_en

Enable RX clock gating, only available when the clock direction is output(not supported on ESP32-C6) the output clock will be controlled by the valid gpio, i.e. high level of valid gpio to enable the clock output, low to disable

uint32_t io_loop_back

For debug/test, the signal output from the GPIO will be fed to the input path as well

uint32_t io_no_init

Deprecated. Driver won't change the GPIO configuration in inilization.

uint32_t allow_pd

Set to allow power down. When this flag set, the driver will backup/restore the PARLIO registers before/after entering/exist sleep mode. By this approach, the system can power off PARLIO's power domain. This can save power, but at the expense of more RAM being consumed.

struct parlio_rx_unit_config_t::[anonymous] flags

RX driver flags

struct parlio_rx_level_delimiter_config_t

Configuration of level delimiter.

Public Members

uint32_t valid_sig_line_id

The data line id of valid/enable signal. The selected data line will be used as the valid/enable signal (i.e. level signal) in this delimiter. As the line of valid/enable signal is shared with the data line, this line_id will be conflict with the data line if set the id within 'data_width', therefore the range is (data_width, PARLIO_RX_UNIT_MAX_DATA_WIDTH].

parlio_sample_edge_t sample_edge

Parallel IO sample edge

parlio_bit_pack_order_t bit_pack_order

Set how we pack the bits into one bytes

uint32_t eof_data_len

Set the data length to trigger the End Of Frame (EOF, i.e. transaction done) interrupt, if the data length is set to 0, that mean the EOF will only triggers when the enable signal inactivated

uint32_t timeout_ticks

The number of source clock ticks to trigger timeout interrupt. Set 0 to disable the receive timeout interrupt The timeout counter starts when the valid/enable signal is invalid/disabled.

uint32_t active_low_en

Set true to set the valid signal active when the level is low, otherwise, the valid signal becomes active when its level is high

struct parlio_rx_level_delimiter_config_t::[anonymous] flags

Extra flags

struct parlio_rx_pulse_delimiter_config_t

Configuration of pulse delimiter.

Public Members

uint32_t valid_sig_line_id

The data line id of valid/enable signal. The selected data line will be used as the valid/enable signal (i.e. pulse signal) in this delimiter. As the line of valid/enable signal is shared with the data line, this line_id will be conflict with the data line if set the id within 'data_width', therefore the range is (data_width, PARLIO_RX_UNIT_MAX_DATA_WIDTH].

parlio_sample_edge_t sample_edge

Parallel IO sample edge

parlio_bit_pack_order_t bit_pack_order

Set how we pack the bits into one bytes

uint32_t eof_data_len

Set the data length to trigger the End Of Frame (EOF, i.e. transaction done) interrupt, if the data length is set to 0, that mean the EOF will only triggers when the end pulse detected, please ensure there is an end pulse for a frame and has_end_pulse flag is set

uint32_t timeout_ticks

The number of source clock ticks to trigger timeout interrupt. Set 0 to disable the receive timeout interrupt The timeout counter starts when the valid/enable signal is invalid/disabled.

uint32_t start_bit_included

Whether data bit is included in the start pulse

uint32_t end_bit_included

Whether data bit is included in the end pulse, only valid when has_end_pulse is true

uint32_t has_end_pulse

Whether there's an end pulse to terminate the transaction, if no, the transaction will be terminated by user configured transaction length

uint32_t pulse_invert

Whether to invert the pulse

struct parlio_rx_pulse_delimiter_config_t::[anonymous] flags

Extra flags

struct parlio_rx_soft_delimiter_config_t

Configuration of soft delimiter.

Public Members

parlio_sample_edge_t sample_edge

Parallel IO sample edge

parlio_bit_pack_order_t bit_pack_order

Set how we pack the bits into one bytes, set 1 to pack the bits into a byte from LSB, otherwise from MSB

uint32_t eof_data_len

Set the data length to trigger the End Of Frame (EOF, i.e. transaction done) interrupt, if the data length is set to 0, that mean the EOF will only triggers when the end pulse detected, please ensure there is an end pulse for a frame and parlio_rx_pulse_delimiter_config_t::has_end_pulse flag is set

uint32_t timeout_ticks

The number of APB clock ticks to trigger timeout interrupt. Set 0 to disable the receive timeout interrupt

struct parlio_receive_config_t

Configuration of a receive transaction.

Public Members

parlio_rx_delimiter_handle_t delimiter

The delimiter of this receiving transaction

uint32_t partial_rx_en

Whether this is an infinite transaction that supposed to receive continuously and partially

uint32_t indirect_mount

This flag only take effect when partial_rx_en is enabled. Enable this flag, an INTERNAL DMA buffer will be mounted to the DMA descriptor instead, The data will be copy to the payload in every interrupt. So that to guarantee the payload buffer is valid during the on_receive_done callback. Either partial_rx_en or indirect_mount is disabled, the user given finite payload will be mounted to the DMA descriptor directly. By default, the user given receive payload will be mounted to the DMA descriptor directly.

struct parlio_receive_config_t::[anonymous] flags

Extra flags

struct parlio_rx_event_data_t

Event callback data.

Public Members

parlio_rx_delimiter_handle_t delimiter

The current delimiter of this receiving event

void *data

The data buffer address that just finished receiving

size_t recv_bytes

The number of received bytes in the data buffer

struct parlio_rx_event_callbacks_t

Parallel IO RX event callbacks.

Public Members

parlio_rx_callback_t on_partial_receive

Callback of received partial data

parlio_rx_callback_t on_receive_done

Callback of receiving transaction done

parlio_rx_callback_t on_timeout

Callback of hardware receiving timeout

Type Definitions

typedef bool (*parlio_rx_callback_t)(parlio_rx_unit_handle_t rx_unit, const parlio_rx_event_data_t *edata, void *user_data)

The template of the Parallel IO RX callback function.

Param rx_unit

[in] Parallel IO RX unit handle that given from ISR

Param edata

[in] The event data that given from ISR

Param user_data

[in] The user specified data that given while registering the callbacks

Return

  • True: to awoke high priority tasks

  • False: not to awoke high priority tasks

Header File

  • components/esp_driver_parlio/include/driver/parlio_types.h

  • This header file can be included with:

    #include "driver/parlio_types.h"

  • This header file is a part of the API provided by the esp_driver_parlio component. To declare that your component depends on esp_driver_parlio, add the following to your CMakeLists.txt:

    REQUIRES esp_driver_parlio

    or

    PRIV_REQUIRES esp_driver_parlio

Type Definitions

typedef struct parlio_tx_unit_t *parlio_tx_unit_handle_t

Type of Parallel IO TX unit handle.

typedef struct parlio_rx_unit_t *parlio_rx_unit_handle_t

Type of Parallel IO RX unit handle.

typedef struct parlio_rx_delimiter_t *parlio_rx_delimiter_handle_t

Type of Parallel IO RX frame delimiter handle.

Header File

Macros

PARLIO_TX_UNIT_MAX_DATA_WIDTH

Maximum data width of TX unit.

PARLIO_RX_UNIT_MAX_DATA_WIDTH

Maximum data width of RX unit.

Type Definitions

typedef soc_periph_parlio_clk_src_t parlio_clock_source_t

Parallel IO clock source.

Note

User should select the clock source based on the power and resolution requirement

Enumerations

enum parlio_sample_edge_t

Parallel IO sample edge.

Values:

enumerator PARLIO_SAMPLE_EDGE_NEG

Sample data on falling edge of clock

enumerator PARLIO_SAMPLE_EDGE_POS

Sample data on rising edge of clock

enum parlio_bit_pack_order_t

Parallel IO bit packing order.

Data in memory: Byte 0: MSB < B0.7 B0.6 B0.5 B0.4 B0.3 B0.2 B0.1 B0.0 > LSB Byte 1: MSB < B1.7 B1.6 B1.5 B1.4 B1.3 B1.2 B1.1 B1.0 > LSB

Output on line (PARLIO_BIT_PACK_ORDER_LSB): Cycle 0 Cycle 1 Cycle 2 —> time GPIO 0: B0.0 B0.4 B1.0 GPIO 1: B0.1 B0.5 B1.1 GPIO 2: B0.2 B0.6 B1.2 GPIO 3: B0.3 B0.7 B1.3

Output on line (PARLIO_BIT_PACK_ORDER_MSB): Cycle 0 Cycle 1 Cycle 2 —> time GPIO 0: B0.4 B0.0 B1.4 GPIO 1: B0.5 B0.1 B1.5 GPIO 2: B0.6 B0.2 B1.6 GPIO 3: B0.7 B0.3 B1.7

Values:

enumerator PARLIO_BIT_PACK_ORDER_LSB

Bit pack order: LSB

enumerator PARLIO_BIT_PACK_ORDER_MSB

Bit pack order: MSB

1

Different ESP chip series might have different numbers of PARLIO TX/RX instances, and the maximum data bus can also be different. For more details, please refer to ESP32-H2 Technical Reference Manual > Chapter Parallel IO (PARLIO) [PDF]. The driver does not forbid you from applying for more driver objects, but it returns error when all available hardware resources are used up. Please always check the return value when doing resource allocation (e.g., parlio_new_tx_unit()).

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