MicroSD to JTAG adapter for ESP32
Convenient adapter PCB for debugging your ESP32 project using a microSD card. The PCB has a space for soldering a 1.27mm header (either a fancy one with a plastic shroud, or a simple set of pins, neither included), and fits directly into the microSD card interface on your project. Then, you can debug your project using JTAG. This works well with the ESP-PROG debug adapter from Espressif (not included), or likely any FTDI debugger that is supported by OpenOCD.
There is also an optional jumper on the bottom of the board for connecting the 3.3 pin on the microSD card to the JTAG adapter; this can be connected if required by your JTAG programmer.
For this to work, your project / development board must have the microSD slot connected to the ESP32 using the 4-line SDMMC adapter on slot 1, with at least the clock, command, data2, and data3 pins wired. This is because the JTAG pins all happen to coincide with the SD pins.
Please note: There are two versions of the adapter; one is just the PCB, and the other has a 1.27" header pre-soldered. The pcb color is black. Happy hacking!