The HI-3717 from Holt Integrated Circuits is a CMOS device designed for interfacing an ARINC 717 compatible bus to a Serial Peripheral Interface (SPI) enabled micro-controller. The part includes selectable Harvard Bi-Phase (HBP) and Bi-Polar Return-to-Zero (BPRZ) channels with encoders/decoders and dedicated line drivers and line receivers for direct connection to the ARINC 717 bus. The part operates from a single +3.3V supply using only four external capacitors. Each transmit and receive channel has a 32-word by 12-bit FIFO for data buffering. The HI-3717 is available in very small 44-pin 7mm x 7mm Chip-scale (QFN) and 44-pin Quad Flat Pack (PQFP) plastic packages.