NXP SC18IM700 UART to I2C master/GPIO Bridge Demoboard


Our SC18IM700 demoboard demonstrates our UART-to-I2C master/GPIO bridge IC. The SC18IM700 bridge IC is ideal for high-speed serial data communication between a UART host and multiple I2C devices over RS-232. Using the demoboard is easy by simply connecting the board to a PC host’s DB9 serial connector and by controlling the board using Microsoft Windows-based software.

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The demoboard includes on-board LEDs, which can also be controlled by the bridge’s programmable GPIO. The demoboard also features our NXP PCA9533 I2C 4-bit LED dimmer and our NXP PCF8570 I2C EEPROM. Using the demoboard software, you can easily control these devices over the RS-232 connection.



The demoboard contains a SC18IM700 UART-to-I2C master/GPIO bridge, which controls the operation of the on-board I2C components. The board contains on-board LEDs connected to an on-board PCA9533 I2C 4-bit LED dimmer. The board contains an on-board PCF8570 I2C EEPROM for storing data on it. Additional on-board LEDs are connected to the GPIO pins of the SC18IM700.

USB Cable

Power is supplied to the demoboard using an included USB cable connected to a USB port on a PC.

Demonstration Program

A Windows-based program is available to control the SC18IM700 demoboard from a PC system with a user-friendly interface. The software allows the user to program the SC18IM700 with the desired I2C speed and to configure the programmable GPIO of the SC18IM700 bridge. The program also provides easy control of the on-board I2C LED dimmer and of the on-board I2C EEPROM device connected to the SC18IM700 bridge. The software can be downloaded from our NXP ICs website below.

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Connect the demoboard to the USB port of the PC using the supplied USB cable to provide power. Connect the demoboard’s DB9 connector to the COM port of a PC directly or with a straight-through (not null-modem) cable (not included).

Two sets of headers are available on the demoboard. The first set is for connecting peripherals such as a pushbutton to the GPIOs of the SC18IM700 bridge. The second set is used for connecting an external I2C slave device.

Using the SC18IM700 Demonstration Program, the demoboard can be easily controlled using three different tabbed screens: General Control, IO Control, and Device Control.

The General Control screen allows you to customize messages sent to the SC18IM700. The messages can be: Read GPIO, Read Register, Write GPIO, Write Register, Power Down, and Start. The messages also include a number of bytes, which can be set easily by incrementing and decrementing the number.

The IO Control screen allows you to configure any of the eight GPIO pins of the SC18IM700 to the following types: input-only, quasi-bidirectional, open-drain, and push-pull. In addition, the IO Control screen allows you to enable and disable the eight GPIO pins individually.

The Device Control screen allows you to control the on-board I2C LED dimmer and I2C EEPROM. The Device Control screen allows you to turn on and turn off the four LEDs attached to the I2C LED dimmer. It allows you to adjust the LEDs blink rate by setting the Pulse Width Modulator (PWM) of the LEDs. The Device Control screen allows you to specify the address and sub-address of the I2C EEPROM. It allows you to write and read number of bytes that are specified.



  • SC18IM700 Demoboard Schematics***


    • SC18IM700 Demonstration Program***