I’d appreciate some very basic advice on CH341x programmers. I know this topic comes up from time to time, but stuff changes, so I hope a refresh is in order. In particular, I see some unexpected things happening with jumper positions.
[My plan is to learn to read and write 24CO2 EEPROMs via I2C. The first target is the one in my Uni-T clamp meter, but before tackling that I have some brand-new EEPROMs to practice on.]
I have two basic Chinese programmers. One is the blue board with a CH341A and two rows of pin headers. To my untrained eye it looks like all the others.
When I couldn’t get that to work I bought a black board with a CH341B and a ZIF socket. Again it looks pretty standard, although it seems to use exclusively 3.3V for the CH341B and the EEPROM.
I tried using flashrom on my Mac, with WCH’s Mac driver, but got nowhere with either board (“No EEPROM found”). I wasn’t sure whether the problem was with the CH341 or the connection to the EEPROM, so I moved to Windows 11, again with the driver downloaded from WCH.
Now as I understand it, to use I2C/SPI the jumpers have to be set correctly: on the black board between pins 1 and 2, and on the blue board in the position that’s closest to the USB plug (and is marked “I2C/SPI” on the board). So far so good.
But with the jumpers in those positions, the Windows Device Manager shows “Unknown device”, with the driver missing, and identifies itself as UART. Windows then offers to find a driver, but fails.
However, when I select what I think ought to be UART (as marked on the blue board, and on the black board by removing the 1–2 jumper), both boards show as serial COM 4, which looks correct, and Device Manager says the driver is in order.
Unfortunately, trying to verify the chip with AsProgrammer then gives: “Error connecting CH341(-1)”.
Any suggestions? That looks to me as if the PC is not talking to the CH341, but for all I know it could be a problem with the 24CO2 itself, or simply confusion between UART and I2C.
The EEPROM is soldered to the little board that came with the programmer, so I’m pretty sure it’s connected correctly. I’m just baffled by the whole thing. Surely I haven’t bought two bad programmers?
[My plan is to learn to read and write 24CO2 EEPROMs via I2C. The first target is the one in my Uni-T clamp meter, but before tackling that I have some brand-new EEPROMs to practice on.]
I have two basic Chinese programmers. One is the blue board with a CH341A and two rows of pin headers. To my untrained eye it looks like all the others.
When I couldn’t get that to work I bought a black board with a CH341B and a ZIF socket. Again it looks pretty standard, although it seems to use exclusively 3.3V for the CH341B and the EEPROM.
I tried using flashrom on my Mac, with WCH’s Mac driver, but got nowhere with either board (“No EEPROM found”). I wasn’t sure whether the problem was with the CH341 or the connection to the EEPROM, so I moved to Windows 11, again with the driver downloaded from WCH.
Now as I understand it, to use I2C/SPI the jumpers have to be set correctly: on the black board between pins 1 and 2, and on the blue board in the position that’s closest to the USB plug (and is marked “I2C/SPI” on the board). So far so good.
But with the jumpers in those positions, the Windows Device Manager shows “Unknown device”, with the driver missing, and identifies itself as UART. Windows then offers to find a driver, but fails.
However, when I select what I think ought to be UART (as marked on the blue board, and on the black board by removing the 1–2 jumper), both boards show as serial COM 4, which looks correct, and Device Manager says the driver is in order.
Unfortunately, trying to verify the chip with AsProgrammer then gives: “Error connecting CH341(-1)”.
Any suggestions? That looks to me as if the PC is not talking to the CH341, but for all I know it could be a problem with the 24CO2 itself, or simply confusion between UART and I2C.
The EEPROM is soldered to the little board that came with the programmer, so I’m pretty sure it’s connected correctly. I’m just baffled by the whole thing. Surely I haven’t bought two bad programmers?
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