The LCD serial adaptor is used to reduce the pinout required for a standard LCD Character module. The adaptor provides interfaces between the LCD module and three different serial interfaces. There is a two wire UART interface, an I2C interface (2 wire) and an SCI interface using 3 or 4 wires. Only one serial interface is used on a particular application.

When first powered up the LCD serial adaptor initializes the LCD module and then polls the three serial interfaces. When a character or command is received on a particular interface the LCD serial adaptor dedicates communication to that interface. From this point on it ignores the other inputs. This behavior is transparent to the user.

The UART interface consists of two pins (Tx and Rx) using TTL levels for easy connection to a microcontroller. The default baud rate is 9600baud. Baud rate can be set to 4800, 9600, 19200 or 38400.

The I2C interface is set as a slave at address 0x76. The I2C interface will support speeds up to 100kHz. There are pull up resistors available for the I2C signals. These can be selected using jumpers on the board.

The SPI interface can be used in 3-wire mode by connecting the CS pin to ground. The SPI interface supports clock speeds up to 100kHz.

The LCD serial adaptor has a 16pin interface for the LCD character module. This interface is very common for LCD character modules. In cases where a backlight is not used only pins 1 to 14 are needed. The documentation shows the typical pinout supported by the LCD serial adaptor.

Features

• Three serial interfaces
• UART interface - Two wire (Data Tx and Data Rx)
• Baud rates of 4800, 9600 (default), 19200 or 38400
• I2C interface - Two wire (SCL and SDA)
• I2C address 0x76, clock speed up to 100kHz
• SPI interface – Three or Four wire (MOSI, MISO, SCLK, SS)
• SPI clock speed up to 100kHz
• Serial interface is automatically detected on power up
• Operates on 5V supply
• Supports 16 pin LCD Modules with backlight (14 pins without backlight)