8 UART chip CH438


CH438 is an eight UART chip with eight asynchronous serial ports compatible with 16C550 or 16C750, and supports communication baud rates up to 4Mbps, it can be used for RS232 serial port expansion of MCU/embedded system, high-speed serial port with automatic hardware rate control, RS485 communication, etc. The figure below is a block diagram of its general application.


  • Fully independent of eight asynchronous serial ports, compatible with 16C550, 16C552, 16C554 and 16C750 and enhanced.
  • Supports 5, 6, 7 or 8 data bits and 1 or 2 stop bits.
  • Supports odd verification, even verification, no verification, blank 0, flag 1 and other verification methods.
  • Programmable communication baud rate, support 115200bps and communication baud rate up to 4Mbps.
  • Built-in 16-byte FIFO fist in fist out buffer, Support for 4 FIFO trigger stages.
  • Support MODEM modem signals CTS, DSR, RI, DCD, DTR, RTS, can be converted to RS232 level by 75232 chip.
  • Supports hardware flow control signals CTS and RTS automatic handshake and automatic transmission rate control, compatible with TL16C550C.
  • Supports serial frame error detection and supports Break line interval detection.
  • Built-in clock oscillator, supports crystals with a frequency range of 0.9216MHz to 32MHz, the default is 22.1184MHz crystal.
  • An 8-bit passive parallel interface with 10MB speed is connected to the microcontroller.
  • The parallel interface consists of an 8-bit data bus, 7-bit address, 3-wire control: chip select input, write operation, and optional read operation.
  • Supports direct address and multiplexed address mode: directly input 7-bit address or control the address from the data bus by the ALE signal.
  • The interrupt output pin is an optional connection, active low, can be replaced by the interrupt flag bit in the Query Register.
  • Support 5V or 3.3V power supply voltage, support serial low-power sleep mode.
  • Available in QFP-44 and SSOP-20 lead-free packages, compatible with RoHS.

relation files

file name file content
CH432DS1.PDF CH432 datasheet. Dual-UART expander. Compatible with 16C550. 8-bit parallel port or SPI to UART. Each UART receive/transmit data independently. Up to 4Mbps baud rate. Can be used for MCU dual-UART expansion. CH432 supports full-duplex/half-duplex/infrared modes.
CH340DS1.PDF CH340 datasheet, USB bus converter chip which converts USB to serial port, printer port, IrDA SIR etc. Integrated clock, supports various operating systems, chip information can be customized, this datasheet is about USB to serial port and USB to Infrared Adapter SIR.
CH341DS1.PDF CH341 datasheet, USB bus converter chip with multiple communication interfaces, such as USB to serial port/parallel port/printer port/I2C interface etc. Drivers support for Windows/Linux/Android/Mac, etc. The datasheet is the description of USB to serial port and printer port.
CH382DS0.PDF CH382 Brief, which converts PCI-Express bus to dual serial ports, and printer/parallel port. Supports up to 8Mbps baud rate, used for PCIE high-speed serial port with automatic hardware flow control, serial ports networking, RS485 communication, parallel/printer port expansion, etc.