Technical info: https://pan.baidu.com/s/1KpKl6mXmcWPbwBXPX1WiCA
LC CH341A USB conversion module equipped with CH341A chip, CH341A is a USB bus adapter chip, through the USB bus to provide asynchronous serial port, parallel port, print and 2 line and 4 line common synchronous serial interface, the module can be used for serial expansion, I2C interface EEPROM，SPI interface FLASH and STC MCU programming, program debugging, data acquisition, brush machine etc.
2. The function and characteristics
● Support USB to parallel printer port and EPP or MEM parallel port ;
● Support USB to UART, I2C, SPI interface;
● The output voltage and the signal level can be selected by 3.3V or 5V;
● Have UART and SPI/I2C working status indicator light;
3. Introduced the hardware and instructions
● The board size: 45*27mm
● The board function description:
● VCC, RXD, TXD, GND: UART interface
● VCC, SDA, SCL, GND: I2C interface
● MISO,MOSI,SCK,CS2,CS1,CS0,GND,VCC: SPI interface
● The 10P_2.54mm pin is print port and EPP/MEM port, pin’s definition can refer to manual.
Work mode ( jumper cap on the right of USB):
(1) UART model: the jumper cap is inserted into the UART, the D2 indicator light (blue) on;
(2) I2C/SPI and EPP/MEM parallel mode: the jumper cap is inserted into the I2C/SPI, the D1 indicator light (red) on;
(3)The printer parallel port mode: the need to unplug the jumpers，and SDA and SCL connected together.
The output voltage of VCC and signal level selection (2 jumper cap on the left of USB):