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Genuine STM32 Blue Pill vs CS32F103C8T6 Clone

I’m troubleshooting a synth design and looking at the data on the SPI bus.  I have 10 STM32 clones (CS32F103C8T6) of the STM32F103C8T6 around and decided to try them out since they have the correct USB resistor.

I was getting the following error in PlatformIO.

Warn : UNEXPECTED idcode: 0x2ba01477

To get the clone to work, I had to change stm32f1x.cfg which I found in C:\Users\YOUR_WINDOWS_USER\.platformio\packages\tool-openocd\scripts\target\

I changed set _CPUTAPID 0x1ba01477 to set _CPUTAPID 0x2ba01477.  If I need to go back to the real Blue Pill, I’ll have to change this back again.

I started with the clone and then switched to the real one.  The scope shows some interesting results.  This is data from the SPI bus.  The circuit is 100% identical in both cases.

CS32F103C8T6 Clone SPI Data

Genuine STM32F103C8T6 SPI Data

I’m not sure if the clone just can’t handle the speed or if there’s some kind capacitance slowing it down.  Regardless, the SPI output of the clone is so bad that I’ll have to check the timing diagrams for my SPI-receiving chip.  I don’t have this problem with the genuine STM32.

If anyone knows a solution to get the clone to behave, please tell me.  Otherwise, I’ll have to view these Chinese clones as WAY too expensive once time is factored in.

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