Espressif ESP32-S2 User Manual

Chapter 2. API Reference
• flags: SPI_TRANS_* flags to control the transaction mode of the transaction to send.
esp_err_t essl_spi_wrdma_done(spi_device_handle_t spi, uint32_t flags)
Send the wrdma_done command to the slave. Upon receiving this command, the slave will stop receiving,
process the received data, and maybe prepare the next buffer to receive.
Note This is required only when the slave is working in segment mode.
Return
• ESP_OK: success
• or other return value from :cpp:func:spi_device_transmit.
Parameters
• spi: SPI device handle representing the slave
• flags: SPI_TRANS_* flags to control the transaction mode of the transaction to send.
Structures
struct essl_spi_config_t
Configuration of ESSL SPI device.
Public Members
spi_device_handle_t *spi
Pointer to SPI device handle.
uint32_t tx_buf_size
The pre-negotiated Master TX buffer size used by both the host and the slave.
uint8_t tx_sync_reg
The pre-negotiated register ID for Master-TX-SLAVE-RX synchronization. 1 word (4 Bytes) will be
reserved for the synchronization.
uint8_t rx_sync_reg
The pre-negotiated register ID for Master-RX-Slave-TX synchronization. 1 word (4 Bytes) will be re-
served for the synchronization.
2.3.14 ESP x509 Certificate Bundle
Overview
The ESP x509 Certificate Bundle API provides an easy way to include a bundle of custom x509 root certificates for
TLS server verification.
Note: The bundle is currently not available when using WolfSSL.
The bundle comes with the complete list of root certificates from Mozilla’s NSS root certificate store. Using the
gen_crt_bundle.py python utility the certificates’subject name and public key are stored in a file and embedded in
the ESP32-S2 binary.
When generating the bundle you may choose between:
• The full root certificate bundle from Mozilla, containing more than 130 certificates. The current bundle was
updated Tue Oct 5 09:35:35 2021 GMT.
• A pre-selected filter list of the name of the most commonly used root certificates, reducing the amount of
certificates to around 35 while still having around 90 % coverage according to market share statistics.
In addition it is possible to specify a path to a certificate file or a directory containing certificates which then will be
added to the generated bundle.
Espressif Systems 662
Submit Document Feedback
Release v4.4

Espressif ESP32-S2 Specifications

General

Brand	Espressif
Model	ESP32-S2
Category	Single board computers
Language	English