Restore SWIO communication on CH32V003 CH32V006

[boda-akos]

Connect WCH-LinkE as usual. Run WCH-Link. Hold reset pin PD7 or PD5 to GND, Query Chip Info 2-3 times while holding reset on GND. Release reset pin, Run the Query again and note that there was communication. Connect reset to GND and run Query 2-3 times again, then quit WCH-Link, switch to Arduino IDE and upload your program with success after that.

[maxint-rd]

Hello @boda-akos - The regular way to restore SWIO communication is to use the Erase using Power Off function of the WCH link utility. Was that method not working for you?

[boda-akos]

I did not know about this method. Still on the learning path ...

[ewpa]

Hello @boda-akos - The regular way to restore SWIO communication is to use the Erase using Power Off function of the WCH link utility. Was that method not working for you?

I found that power-off erase function does not work for CH32V006 or CH32V002. I'd love to revive my growing pile of dead chips. Any hints?

[maxint-rd]

I found that power-off erase function does not work for CH32V006 or CH32V002. I'd love to revive my growing pile of dead chips. Any hints?

A pile of dead V006/V002? What did you do?

Have you updated your LinkE to the latest version? You also need to update the WCH Link Utility. I'm using v2.40.

When you connect them on a bare adapter board using only GND/5V/SWIO, do you get any response? (note: use short wires and don't use anything else, no caps or other passives either)

For my V002/V006 update of the EEPROM library, I did need to do the power-off erase a few times and then it worked, just the same as for V003. But be sure to select CH32V002/4/5/6/7 in the Series listbox of the WCH Link Utility.

[ewpa]

For V002, I'm converting from 8-pin V003 and needed the SWIO pin as output. I also seemed to brick one before I updated LinkE to 2.15. Waiting for some DIP-8 adapters to arrive in the mail.

[maxint-rd]

Okay. I just tested Power-Off Erase on a programmed V002. It cleared it and I could reprogram it. I only have the TSSOP20 package of V002/V006, so I can't confirm it for SOP8.

For my development on breadboard I mainly use plain breakout PCB's, but I also have pushdown socket adapters for both SOP8 and SOP16. Quite handy if you want to program chips prior to soldering them to a PCB.

[ewpa]

That's good to know. Power-off erase is not working for me even if the chip is responding to normal programming. I've got some QFN-12 and QFN-20 on the way with adapters, so I will retry soon.

[maxint-rd]

Power-off erase is not working for me even if the chip is responding to normal programming.

When you use the WCH Link Utility, do you get good results when you query the chip? (eg. do you see proper chip ID and memory size?)

What does the utility say when you query write/read protection?

[ewpa]

I saw nothing being read back, as if the chip were missing. I have since reworked that board, but still have the chip ready for when my DIP-8 breakout boards arrive. I've also lined up power, ground and SWIO, so it can plug straight into the LinkE, no wires.

[boda-akos]

Hello @boda-akos - The regular way to restore SWIO communication is to use the Erase using Power Off function of the WCH link utility. Was that method not working for you?

I found that power-off erase function does not work for CH32V006 or CH32V002. I'd love to revive my growing pile of dead chips. Any hints?

Hello, I only had one or two chips and revived them with the method as described, not with the Erase using Power Off. Sorry, but I can not help more. Since then, had no bricked chips.

[maxint-rd]

I saw nothing being read back, as if the chip were missing. I have since reworked that board, but still have the chip ready for when my DIP-8 breakout boards arrive. I've also lined up power, ground and SWIO, so it can plug straight into the LinkE, no wires.

I saw that when I used old (not updated) versions of the LinkE and Link Utility. I also saw it when using a breadboard with kind-of loose grip on the SWIO jumper wire, ie. a bad connection.

Looking forward to see how your bare chip responds. Please share here.
Somewhere I read having a PCB with bypass capacitors between VCC/GND might also mess the Power Off Erase process up. Another tip is (during development) to start Setup() with a delay before reassigning the pin. Good luck!

[ewpa]

Upgraded LinkE firmware from 2.15 to 2.18. Power-off erase functions on working V002 (though I did not try making the SWIO pin as output). For the bricked V002, no result. Always get "the chip type is mismatched or status of chip is wrong". My earlier toolchain (hardware and software) was set for V003 before I started all this, so wonder if this somehow caused read and write protect to be enabled?

I cannot try the PD7/PD5 method since those pins are not available on the 8-pin chip.

However, for now I am moving back to V003. I'm having a lot of other (unrelated to this) issues with porting to V002.

[maxint-rd]

Upgraded LinkE firmware from 2.15 to 2.18. Power-off erase functions on working V002 (though I did not try making the SWIO pin as output). For the bricked V002, no result.

I guess when it works on other V002 chips, the utility is working okay. (FYI: the WCH Link Utility I'm using version 2.40). I've destroyed some chips in High Voltage experiments. Their only response to VCC/GND now is that they get quite hot.

BTW. For programming/debugging the V002/V006 from the Arduino IDE it's also necessary to update to a newer version of WCH's variant of OpenOCD (see also this readme).

so wonder if this somehow caused read and write protect to be enabled?

Could be. When working on EEPROM support for V002 I've corrupted the system configuration memory a couple of times, resulting in read/write protect to be enabled. Using the unprotect feature of the Link Utility I could restore it. Some other bits in the same area configure other settings, possibly giving behavior as you described.

I cannot try the PD7/PD5 method since those pins are not available on the 8-pin chip.

Indeed. The CH32V002J4M6 (SOP8) has no pin for RST. Somewhere I read a post where someone revived his chip by connecting a crystal. For SOP8 (V003 and V002) the Crystal pins X1 and X0 are on pins 1 and 3. According the reference manual such configuration requires crystal and two load capacitors. (I've not used crystals myself other than on the V003 EVT board).

However, for now I am moving back to V003. I'm having a lot of other (unrelated to this) issues with porting to V002.

What kind of other issues do you have? I've made a bunch of improvements for V002. Most of them I shared in PR #200. I have some projects that I wanted to use on V002/V006 for better ADC and for debugging. It resulted in the need to make those improvements. Maybe your issues are related, (I've not tested everything yet, so perhaps I still need to encounter your V002 issues). Can you perhaps open a new issue for those V002 issues or add a comment in PR #200 listing them?

[boda-akos]

Well again I had a bricked CH32V006 restored. Power cycle did not work, because after switching to external crystal I did this stupidity : "Disable HSI if HSE is stable RCC->CTLR &= ~RCC_HSION;" this bricked SWD. But, success story follows. To begin with, we can exclude any hardware fault, there was none. I had to run WCH Link-Utility V2.50, Query Chip Info while holding the Reset pin of the CH32 to GND, and do this 3 times. Releasing the Reset the Query Chip Info was working already. After this I switched to Arduino IDE and repeated the program download the same way , holding the Reset to GND two times, releasing the third time, and see miracle the upload is working since then.