5, the on-board CH340C chip as USB to TTL communication use, connected to the master chip serial port 1, but also as ISP burn-in use. STM32F103RCT6, TQFP64, FLASH: 256K, RAM: 48K. 3, with IIC/SPI/CAN/UART/USB interfaces and DAC/ADC/DMA peripherals.
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