Hello good people,
I have been working on a project using esp32 and debugging works great when i use the adbus (20pins internal row) using the ft2232hl v3 board, However when i try to hook up jtag to the external (10x2 row, bdbus) header, the led4 is glowing red and openocd is unable to locate the device.. i have tried hooking up the minimal setup; tdo, tdi, tms, tck, gnd and vcc and also tried adding the reset and the vtref but to no avail, is this a hardware configuration issue or maybe an openocd one? do i need to tell the driver/openocd to use the bdbus instead somehow?

the led4 seem to turn on red only when i connect the TDI pin, hopes this help

Would love to get some assistant regrading this issue or maybe understand what am i doing wrong
Best regards

Hi,

this repo saved me quite a lot of time after I bought the board (V1). But I've found out that both V1 and V2 boards have bug on silkscreen – for SWD to function properly, you need two things:

1. Bridge BD1 and BD2 with resistor (V2 has built-in jumper for that, V1 doesn't = you need to do that manually).
2. Connect ARM's (or whatever device are you connecting to via JTAG) SWDIO pin to FT2232HL's pin BD2 (or AD2 if you're using the other half of FT2232HL).

However labels on PCB suggest that SWDIO from processor should be connected to connector CN4 pin 7 = BD3 (on V1) or connector CN4 pin = BD1 (on V2).

Could you please note that bug via warning to PDF schematics?

On U4, disconnect +3V3 from pin 5 and connect VBUS to pin 5 instead, otherwise 20KV or more will pass through the system during an ESD discharge. Remove USB shield from ground. Connect the USB shield and GND together with a 4.7nF 3KV or higher capacitor, parallel to a 1M resistor 3KV or higher. Pins 1 and 6 can be connected together, and pins 3 and 4 can be connected together on U4 for double protection.

There doesn't seem to be a reason for +3V3 to be connected to U5 and U6. In all cases make sure the grounds are connected and routed safely away from the rest of the circuit on a separate track(s) back to the USB ground or shield. On the computer, the shield ground is coupled to earth ground (or should be).

On CN1 connect a 5V TVS diode to VBUS close to pin 2 to the shield ground, and on CN2, connect a 3.3V TVS diode close to pins 2 and 3 to the shield ground. More diode array ICs can be used for the remaining pins on CN1 and CN2 if desired.

A Common Mode Choke can be used on the USB data lines instead of resistors R5 and R6 to filter EMI, like a Wurth 744232090 (90Ohm, 100MHz, 370mA, 1206 (3216 metric)).