HI-35850PQT

The HI-35850PQT by Holt Integrated Circuits Inc. is a silicon gate CMOS device that facilitates the connection between a Serial Peripheral Interface (SPI) enabled microcontroller and the ARINC 429 serial bus. This IC serves as a direct replacement for the HI-3585, featuring an enhanced SPI interface capable of 12 MHz operation, significantly boosting host efficiency.

The device includes a receiver with user-programmable label recognition for any of the 256 possible labels, a 32x32 Receive FIFO, and an analog line receiver. The independent transmitter is equipped with a 32x32 Transmit FIFO and an integrated line driver. Monitoring the status of both transmit and receive FIFOs can be achieved via a programmable external interrupt pin or by polling the HI-35850 Status Register.

Additional features include a programmable option for data or parity in the 32nd bit and the ability to alter the bit-significance of ARINC 429 labels. The pins offer flexible input and output resistance values, aiding in the integration of external lightning protection circuitry. The SPI and control signals are compatible with CMOS and TTL standards and support both 3.3V and 5V operation. The ARINC 429 databus timing is derived from a 1 MHz clock input or an internal counter linked to higher clock frequencies.

The HI-35860 variant is identical in function but provides digital transmitter output pins instead of a built-in line driver, allowing for the use of external line drivers like the HI-8592, HI-8596, or HI-8597.