[JTAG] [openocd] Error: JTAG scan chain interrogation failed: all ones

[aldecei]

So I have that error since severals weeks and tried many solutions but no one worked.

Hardware
- Esp32 devkit v1
- Wroom32 With Jtag port (those 6 little dots)
- jtag interface: ftdi ft2232H

Problem
I type:

bin\openocd -s share\openocd\scripts -f interface\ftdi\esp32_devkitj_v1.cfg -f board\esp-wroom-32.cfg

I get:

adapter speed: 20000 kHz
esp32 interrupt mask on
Info : ftdi: if you experience problems at higher adapter clocks, try the command "ftdi_tdo_sample_edge falling"
Info : clock speed 20000 kHz
Error: JTAG scan chain interrogation failed: all ones
Error: Check JTAG interface, timings, target power, etc.
Error: Trying to use configured scan chain anyway...
Error: esp32.cpu0: IR capture error; saw 0x1f not 0x01
Warn : Bypassing JTAG setup events due to errors

Here is what I tried:
- checked the wire
- checked the jtag connections (esp32 side and ftdi side)
- changed the wire
- checked the supply voltage
- checked ALL the pins if they where low/high/floating
- changed the usb drivers with zadig
- changed the chip (i got the same error with esp32 dev kit or wroom32)
- reseted with the EN pin
- forced boot mode (gpio0= 0 and gpio2=0)
- forced spi mode (gpio0= 1 and gpio2=~)
- tried the command "ftdi_tdo_sample_edge falling"
- changed the jtag interface: i took a seeger jlink (but it's worse)
- changed the computer: i worked on a computer that used to flash wroom32 with ft2232H in the past.



But something strange occured
I flashed a blink program in the esp32 devkit via USB. Then the error "All one" vanished and from here, I could use jtag connexion.
But I can't do the same with the Wroom32, it only has jtag port.

If anyone has a little idea on what the heck is happening I would be glad to hear it...

Thank you

[aldecei]

Just found an explanation.
Somehow, the ft2223h forces some pin to 2.5v and so those pin are considered as "high", that's why I got the "all one" error. This 2.5v level is constant and can't be changed so no information can be exchanged.

So I guess my ft2232h jtag interface is broken.