NXP SC18IS600 SPI Slave to I2C Master/GPIO Bridge Demoboard


The SC18IS600 demoboard demonstrates our SPI slave-to-I2C master/GPIO bridges. These bridges are ideal for high-speed serial data communication between an SPI host and multiple I2C devices. The demoboard connects to a host processor via an SPI-bus interface and connects to an I2C slave device via header pins. The demoboard contains on-board LEDs, which can be controlled by the bridge’s programmable GPIO. In addition, the demoboard allows the SPI host to operate an on-board I2C LED dimmer and an on-board I2C EEPROM via the SPI bus interface.
The SC18IS600 bridge IC features SPI speeds up to 1.2Mbps using an internal oscillator whereas our SC18IS601 bridge IC features SPI speeds up to 3Mbps using an external oscillator. Both bridges feature I2C speeds up to 400KHz. The SC18IS600 demoboard includes our SC18IS600 bridge which can be replaced with our SC18IS601 bridge IC and used with an external oscillator by advanced users.

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The demoboard also features the NXP PCA9533 I2C 4-bit LED dimmer and the NXP PCF85103C-2 I2C EEPROM.



The demoboard features the SC18IS600 bridge. The demoboard also contains an I2C LED dimmer, on-board I2C EEPROM, and LEDs which can be controlled by the bridge’s GPIO. Headers are provided for connecting to the demoboard. Three push buttons are provided to control the demoboard, generating input signals. The SC18IS600 bridge on the demoboard may be optionally desoldered and replaced with a SC18IS601 bridge and external oscillator. When using an SC18IS601 bridge, JP3 is set accordingly. Other jumper switches are for internal use and testing only.

Sample Code

In order to connect to the demoboard, an SPI master is required. NXP Semiconductors provides sample code routines which run on our LPC900 family of microcontrollers. Other microcontrollers or embedded processors with an SPI master interface can be used to communicate with the SC18IS600 bridge on the demoboard. The routines for the LPC900 MCU can be ported as necessary. The routines include SPI host initialization, SPI read and write routines, bridge configuration, and I2C slave device commands. The sample code is downloadable from our ICs website below.

Test Program

An SC18IS600 Test Program is available for operating the demoboard. The test program is used in conjunction with hardware and software available from The Boardshop. The Boardshop’s Win-I2CUSBDLL adapter provides an SPI master interface via a PC’s USB port. After installing the Win-I2CUSB software, the NXP Test Program can be loaded. Using buttons in the Test Program GUI, you can easily send SPI commands to control I2C slave devices.

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The SC18IS600 demoboard gets its power from the SPI host. The SPI host interfaces with the demoboard via the SPI headers. The SPI host can be a microcontroller or an embedded processor with an SPI-bus port. The SPI host can communicate with multiple on-board I2C slave devices (I2C LED dimmer and I2C EEPROM) by sending SPI commands to the SC18IS600 bridge.

There are also various headers available on the demoboard. I2C headers can be used to connect an external I2C slave device. Peripherals such as LEDs can be connected to the I/O headers that interface with the programmable GPIO of SC18IS600.

The demoboard contains three switches. The first is a reset for the SC18IS600 bridge. After the bridge is reset, the device will be initialized with the default values. The second switch is connected to one of the programmable GPIO that can be programmed as an input. The third switch is used to wake up the device when the device is in the power-down mode which reduces the power consumption significantly.