I have a custom board with an ESP32 WROOM-32U. When I attempt to upload software via JTAG (J-Link), I get a timeout. I already checked on the following: ESP32 has a stable power supply JTAG pinning is correct J-Link upload works on other ESP32 boards without a problem Adapter speed changes (e.g. …

Good news :smiley: It works now! I don’t know why but after one week of trial and error it works now… I had to flash it first over serial and since then it works… This is very strange. EDIT: As you can see in the schematic I forgot to put a decoupling capacitor between ESP 3.3V and GND pins. Alth…

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ESP32 WROOM-32 and JTAG timeout

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maxgerhardt April 2, 2020, 7:53pm 2

The adapter only ever sees a HIGH output on the data line.

Have you tried dialing that down a bit? See ESP32 + J-link debugger does not start - #12 by Yourigh