National Instruments 779553-01 I²C/SPI Interface Device

The 779553-01 from National Instruments is a master interface that is part of the USB-8451 model family. It is made to work seamlessly with devices that are serial peripheral interface (SPI), System Management Bus (SMBus), and inter-integrated circuit (I²C) compatible. This portable solution makes it easier to interface with integrated circuits and consumer devices thanks to its plug-and-play USB connectivity.

With its ability to operate at up to 12 MHz for SPI and 250 kHz for I²C, the 779553-01 enables effective data transfer in a range of applications. It features eight general-purpose digital I/O lines that can be used for LED toggling or setting I²C device addresses, among other things. Because of these capabilities, it's a great option for engineers who want to place the interface closer to the I²C/SPI devices than PCI interfaces in order to limit the length of the I²C bus and minimize noise issues.

The 779553-01 OEM is a full-speed USB 2.0 device, providing robust connectivity options for both I²C and SPI protocols. It provides a great deal of flexibility for a range of control and monitoring activities because of its eight SPI chip selections and eight general-purpose digital I/O channels. Precise control over digital signals is possible because each of the eight single-ended digital lines (P0.<0..7>) can be independently configured as either static digital input (DI) or digital output (DO) lines. The DIO port can be made to function at 5 V by adding an external pull-up resistor to its default configuration, which allows it to function in a push-pull mode at 3.3 V.

Along with an input for MISO (SDI), the 779553-01's SPI interface comprises outputs for SPI chip select (CS <0..7>), MOSI (SDO), and clock (SCLK). An absolute voltage range of -0.5V to +5.8V with respect to ground is supported by the push-pull mode-driven SPI signals. A broad variety of SPI devices can be used with this interface because it supports an 8-bit transmission size.

Standard mode clock rates (32kHz to 100kHz) and fast mode clock rates (125kHz to 250kHz) are supported via the 779553-01's I²C interface, which has both SDA and SCL lines. It is incompatible with High-Speed Mode and Fast Mode Plus. Reliability and the avoidance of harm to connected devices are guaranteed by the open-drain driver type and power-on high impedance state.