The HS-3282 is a high performance CMOS bus interface
circuit that is intended to meet the requirements of ARINC
Specification 429, and similar encoded, time multiplexed
serial data protocols. This device is intended to be used with
the HS-3182, a monolithic Dl bipolar differential line driver
designed to meet the specifications of ARINC 429. The
ARINC 429 bus interface circuit consists of two (2) receivers
and a transmitter operating independently as shown in
Figure 1. The two receivers operate at a frequency that is
ten (10) times the receiver data rate, which can be the same
or different from the transmitter data rate. Although the two
receivers operate at the same frequency, they are
functionally independent and each receives serial data asynchronously.
The transmitter section of the ARINC bus
interface circuit consists mainly of a First-In First-Out (FIFO)
memory and timing circuit. The FIFO memory is used to hold
up to eight (8) ARINC data words for transmission serially.
The timing circuit is used to correctly separate each ARINC
word as required by ARINC Specification 429. Even though
ARINC Specification 429 specifies a 32-bit word, including
parity, the HS-3282 can be programmed to also operate with
a word length of 25 bits. The incoming receiver data word
parity is checked, and a parity status is stored in the receiver
latch and output on Pin BD08 during the 1st word. [A logic
“0” indicates that an odd number of logic “1” s were received
and stored; a logic “1” indicates that an even number of logic
“1”s were received and stored]. In the transmitter the parity
generator will generate either odd or even parity depending
upon the status of PARCK control signal. A logic “0” on
BD12 will cause odd parity to be used in the output data
stream.