essl_spi_rddma() function

Receive long buffer in segments from the slave through its DMA.

Syntax

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Summary

Declaration

Definition

from essl_spi.h:230

esp_err_t essl_spi_rddma(spi_device_handle_t spi, uint8_t *out_data, int len, int seg_len, uint32_t flags);

Implemented in essl_spi.c:184

Arguments

Argument

Description

spi

SPI device handle representing the slave

out_data

Buffer to hold the received data, strongly suggested to be in the DRAM and aligned to 4

len

Total length of data to receive.

seg_len

Length of each segment, which is not larger than the maximum transaction length allowed for the spi device. Suggested to be multiples of 4. When set < 0, means send all data in one segment (the ``rddma_done`` will still be sent.)

flags

`SPI_TRANS_*` flags to control the transaction mode of the transaction to send.

Return value

- ESP_OK: success - or other return value from :cpp:func:`spi_device_transmit`.

Notes

This function combines several :cpp:func:`essl_spi_rddma_seg` and one :cpp:func:`essl_spi_rddma_done` at the end. Used when the slave is working in segment mode.

Examples

References

from examples

essl_spi_rddma() function

Syntax

Arguments

Return value

Notes

Examples

References

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