Configure Other JTAG Interfaces

[中文]

For guidance about which JTAG interface to select when using OpenOCD with ESP32-S3, refer to the section Selecting JTAG Adapter. Then follow the configuration steps below to get it working.

Configure eFuses

By default, ESP32-S3 JTAG interface is connected to the built-in USB_SERIAL_JTAG peripheral. To use an external JTAG adapter instead, you need to switch the JTAG interface to the GPIO pins. This can be done by burning eFuses using espefuse.py tool.

  • Burning DIS_USB_JTAG eFuse will permanently disable the connection between USB_SERIAL_JTAG and the JTAG port of the ESP32-S3. JTAG interface can then be connected to GPIO39-GPIO42. Note that USB CDC functionality of USB_SERIAL_JTAG will still be usable, i.e., flashing and monitoring over USB CDC will still work.

  • Burning STRAP_JTAG_SEL eFuse will enable selection of JTAG interface by a strapping pin, GPIO3. If the strapping pin is low when ESP32-S3 is reset, JTAG interface will use GPIO39-GPIO42. If the strapping pin is high, USB_SERIAL_JTAG will be used as the JTAG interface.

Warning

Burning eFuses is an irreversible operation, so please consider the above option before starting the process.

Configure Hardware

  1. Identify all pins/signals on JTAG interface and ESP32-S3 board that should be connected to establish communication.

    ESP32-S3 pins and JTAG signals

    ESP32-S3 Pin

    JTAG Signal

    MTDO / GPIO40

    TDO

    MTDI / GPIO41

    TDI

    MTCK / GPIO39

    TCK

    MTMS / GPIO42

    TMS

  2. Verify if ESP32-S3 pins used for JTAG communication are not connected to some other hardware that may disturb JTAG operation.

  3. Connect identified pin/signals of ESP32-S3 and JTAG interface.

Configure Drivers

You may need to install driver software to make JTAG work with computer. Refer to documentation of your JTAG adapter for related details.

On Linux, adding OpenOCD udev rules is required and is done by copying the udev rules file into the /etc/udev/rules.d directory.

Connect

Connect JTAG interface to the computer. Power on ESP32-S3 and JTAG interface boards. Check if the JTAG interface is visible on the computer.

To carry on with debugging environment setup, proceed to section Run OpenOCD.

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