How can I debug using WCH-LinkE Adapter

[snoop911]

According to the CH569W documentation, SWDIO is on PA11 , and SWCLK is on PA10. Following those signals to the header, I connect it to the corresponding pins of the WCH-LinkE-R0-1v2 adapter.

However, even the official MounRiver Studio nor WCH-LinkUtility see the WCH569.. but they do see the WCH-LinkE. I believe the LinkE is correctly in RiscV mode because a single red LED on. (Pressing mode while powering the LinkE it shows both RED and blue LEDs.. ARM mode).

The 3.3v / 1.2v on the target board looks good, so not sure what it could be. The chip's datasheet suggests that the SWD mode can be disabled? Perhaps the chip has been pre-flashed to disable it?

[bvernoux]

You shall flash a firmware with Debug Enable all is written in https://github.com/hydrausb3/wch-ch56x-isp => -d, --mcudebug=VALUE Set MCU debug mode on or off
See also https://github.com/hydrausb3/wch-ch56x-isp?tab=readme-ov-file#ch56x-debug-mode

[snoop911]

I'm trying to use the SWD interface so that I can debug and step-thru the code. The DEBUG_EN is on, yet MounRiver / WCH-LinkUtility don't see the target (but do see the WCH-LinkE)

Since there's only 3 wires: swclk (P3.14), swdio (P3.2), and ground, I figure this should be a small dunk yet not sure what I'm missing.

[bvernoux]

There are a few things to clarify:

1. CH569 uses 2-wire SDI (Serial Debug Interface), not ARM SWD.
   Although the pin names look similar (SWDIO/SWCLK), the protocol is completely different.
   The CH569 is a RISC-V chip and uses WCH's proprietary 2-wire SDI debug interface, which is not compatible with standard ARM SWD.

2. WCH-LinkE mode: Make sure your WCH-LinkE is in LinkRV mode (RISC-V), not ARM mode.
   A single red LED typically indicates RISC-V mode, which seems correct based on your description.

3. DEBUG_EN: As mentioned, DEBUG_EN must be enabled. You can verify with:

   wch-ch56x-isp -c
   

   Look for [5] DEBUG_EN 1: enabled. If it shows 0: disabled, enable it with:

   wch-ch56x-isp -d=on
   

   Warning: After any change to CH56x Debug mode old binary previously flashed will not run correctly, so it is mandatory to flash the program again with a binary like in example How to use wch-ch56x-isp
   See: https://github.com/hydrausb3/wch-ch56x-isp?tab=readme-ov-file#ch56x-debug-mode

4. CH569 debug constraint: Per the WCH-Link manual: "When using the debug function of CH569, the user code must be smaller than the configured ROM space." If your code exceeds the ROM partition, debugging won't work.

5. Practical limitation:
   I do not recommend using any debugger with WCH CH569 when working with USB3 or other fast peripherals (which use those pins like HSPI).
   The debug interface is very slow and will break USB enumeration timing when stepping through code or hitting breakpoints.
   For most HydraUSB3 development, printf-style debugging via fast UART (or even SerDes but requires an other WCH CH569 to capture and display the SerDes data) is more practical.

For WCH-LinkE specific support, you may want to ask where you purchased your adapter, or check WCH's official resources.