HI-3585 The HI-3585 from Holt Integrated Circuits is a silicon gate CMOS device for interfacing a Serial Peripheral Interface (SPI) enabled microcontroller to the ARINC 429 serial bus. The device provides one receiver with user-programmable label recognition for any combination of 256 possible labels, 32 x 32 Receive FIFO and analog line receiver. The independent transmitter has a 32 x 32 Transmit FIFO and built-in line driver. The status of the transmit and receive FIFOs can be monitored using the programmable external interrupt pin, or by polling the HI-3585 Status Register. Other features include a programmable option of data or parity in the 32nd bit, and the ability to switch the bit-signifiance of ARINC 429 labels. Pins are available with different input resistance and output resistance values which provides flexibility when using external lightning protection circuitry.
The Serial Peripheral Interface minimizes the number of host interface signals resulting in a small footprint device that can be interfaced to a wide range of industry-standard microcontrollers supporting SPI. Alternatively, the SPI signals may be controlled using just four general purpose I/O port pins from a microcontroller or custom FPGA. The SPI and all control signals are CMOS and TTL compatible and support 3.3V or 5V operation.
The HI-3585 applies the ARINC 429 protocol to the receiver and transmitter. ARINC 429 databus timing comes from a 1 MHz clock input, or an internal counter can derive it from higher clock frequencies having certain fixed values, possibly the external host processor clock.
