SourceVuESP-IDF Framework and ExamplesESP-IDFesp_hmac_jtag_enable()

esp_hmac_jtag_enable() function

Use HMAC peripheral in Downstream mode to re-enable the JTAG, if it is not permanently disabled by HW. In downstream mode, HMAC calculations performed by peripheral are used internally and not provided back to user.

Syntax

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Summary

Declaration

from esp_hmac.h:81

esp_err_t esp_hmac_jtag_enable(hmac_key_id_t key_id, const uint8_t *token);

Arguments

Argument

Description

key_id

Determines which of the 6 key blocks in the efuses should be used for the HMAC calculation. The corresponding purpose field of the key block in the efuse must be set to HMAC downstream purpose.

token

Pre calculated HMAC value of the 32-byte 0x00 using SHA-256 and the known private HMAC key. The key is already programmed to a eFuse key block. The key block number is provided as the first parameter to this function.

Return value

* ESP_OK, if the key_purpose of the key_id matches to HMAC downstread mode, The API returns success even if calculated HMAC does not match with the provided token. However, The JTAG will be re-enabled only if the calculated HMAC value matches with provided token, otherwise JTAG will remain disabled. * ESP_FAIL, if the key_purpose of the key_id is not set to HMAC downstream purpose or JTAG is permanently disabled by EFUSE_HARD_DIS_JTAG eFuse parameter. * ESP_ERR_INVALID_ARG, invalid input arguments

Notes

Return value of the API does not indicate the JTAG status.

Examples

esp_hmac_jtag_enable() is referenced by 1 libraries and example projects:

References

from examples

esp_hmac_jtag_enable() function

Syntax

Arguments

Return value

Notes

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