HI-8599

The HI-8599 from Holt Integrated Circuits is silicon gate CMOS device for interfacing a 16-bit parallel data bus directly to the ARINC 429 serial bus. The device provides two receivers, an independent transmitter and line driver capability in a single package. The receiver input circuitry and logic are designed to meet the ARINC 429 specifications for loading, level detection, timing, and protocol.

The transmitter section provides the ARINC 429 communication protocol and the line driver circuits provide the ARINC 429 output levels. The ARINC 429 line driver outputs can be forced to a null state at any time with the TEST input. The 16-bit parallel data bus exchanges the 32-bit ARINC data word in two steps when either loading the transmitter or interrogating the receiver. The data bus interfaces with both CMOS & TTL.

The HI-8599 has 10 ohms in series with each ARINC output so that an additional 27.5 ohm series resistance may be added externally for lightning protection while still matching the differential 75 ohm characteristic impedance of the ARINC bus. Each independent receiver monitors the data stream with a sampling rate of 10 times the data rate. The sampling rate is software selectable at either 1 MHz (High Speed) or 125 KHz (Low Speed).

The results of a parity check are available as the 32 ARINC bit. The HI-8599 examines the null and data timings and will reject erroneous patterns. For example, with a 125 KHz (Low Speed) clock selection, the incoming data frequency must be between 10.4 KHz and 15.6 KHz. The transmitter has a First In, First Out (FIFO) memory to store 8 ARINC words for transmission. The data rate of the transmitter is software selectable by dividing the master clock, CLK, by either 10 or 80. The master clock is used to set the timing of the ARINC Transmission within the required resolution.