4-bit eMMC slot colliding with JTAG

Xavi92
Posts: 45
Joined: Thu Mar 28, 2019 2:26 pm

4-bit eMMC slot colliding with JTAG

Postby Xavi92 » Tue Sep 15, 2020 8:46 am

According to the documentation, only two pin configurations are available for the SDMMC host peripheral. We want to replace an already working SD card interfaced via SPI by eMMC storage, but the 4-bit slot available on the ESP32 is connected to the same pins as the JTAG inteface. (GPIO 12, 13, 14 and 15).

Does this mean it is not possible to interface eMMC storage with minimum number of pins without sacrificing JTAG?

Xavi92
Posts: 45
Joined: Thu Mar 28, 2019 2:26 pm

Re: 4-bit eMMC slot colliding with JTAG

Postby Xavi92 » Fri Sep 18, 2020 6:34 am

Does anyone know any solution to this issue?
Thank you very much.

WiFive
Posts: 2979
Joined: Tue Dec 01, 2015 7:35 am

Re: 4-bit eMMC slot colliding with JTAG

Postby WiFive » Sat Sep 19, 2020 8:54 pm


Xavi92
Posts: 45
Joined: Thu Mar 28, 2019 2:26 pm

Re: 4-bit eMMC slot colliding with JTAG

Postby Xavi92 » Tue Sep 22, 2020 6:22 am

Thank you for your reply. Then I assume there is no (clear) solution to this so source-level debugging needs to be sacrificed if SDMMC is used on the JTAG pins.

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