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5-187
Operational Description
The HS-3282 is designed to support ARINC Specification
429 and other serial data protocols that use a similar format
by collecting the receiving, transmitting, synchronizing,
timing and parity functions on a single, low power LSl circuit.
It goes beyond the ARlNC requirements by providing for
either odd or even parity, and giving the user a choice of
either 25 or 32-bit word lengths. The receiver and transmitter
sections operate independently of each other. The serial-to-
parallel conversion required of the receiver and the parallel-
to-serial conversion requirements of the transmitter have
been incorporated into the bus interface circuit.
Provisions have been made through the external clock input
to provide data rate flexibility. This requires an external clock
that is 10 times the data rate.
To obtain the flexibility discussed above, a number of
external control signals are required, To reduce the pin count
requirements, an internal control word register is used. The
control word is latched from the data bus into the register by
the Control Word Strobe (CWSTR) signal going to a logic
“1”. Eleven (11) control functions are used, and along with
the Bus Data (BD) line are listed below:
ARlNC 429 DATA FORMAT as input to the Receiver and out-
put from the Transmitter is as follows:
This format is shuffled when seen on the sixteen bidirec-
tional input/outputs. The format shown below is used from
the receivers and input to the transmitter:
Control Word
PIN NAME
SYMBOL
FUNCTION
BD05
SLFTST
Connects the self test signal from the transmitter directly to the receiver shift registers, bypassing the input
receivers. Receiver 1 receives Data True and Receiver 2 receives Data Not. Note that the transmitter output
remains active. (Logic “0” on SLFTST Enables Self Test).
BD06
SDENB1
Signal to Activate the Source/Destination (S/D) Decoder for Receiver 1. (Logic “1” activates S/D Decoder).
BD07
X1
If SDENB1 = “1” then this bit is compared with ARlNC Data Bit #9. If Y1 also matches (see Y1), the word will be
accepted by the Receiver 1. If SDENB1 = “0” this bit becomes a don’t care.
BD08
Y1
If SDENBI = “1” then this bit is compared with ARINC Data Bit #10. If X1 also matches (see X1), the word will
be accepted by the Receiver 1. If SDENB1 = “0” this bit becomes a don’t care.
BD09
SDENB2
Signal to activate the Source/Destination (S/D) Decoder for Receiver 2. (Logic “1” activates S/D Decoder).
BD10
X2
If SDENB2 = “1” then this bit is compared with ARlNC Data Bit #9. If Y2 also matches (see Y2), the word will be
accepted by the Receiver 2. If SDENB2 = “0” this bit becomes a don’t care.
BD11
Y2
If SDENB2 = “1” then this bit is compared with ARINC Data Bit #10. If X2 also matches (see X2), the word will
be accepted by the Receiver 2. If SDENB2 = “0” this bit becomes a don’t care.
BD12
PARCK
Signal used to invert the transmitter parity bit for test of parity circuits. Logic “0” selects normal odd parity. Logic
“I” selects even parity.
BD13
TXSEL
Selects high or low Transmitter data rate. If TXSEL = “0” then transmitter data rate is equal to the clock rate
divided by ten (10). If TXSEL = “1” then transmitter data rate is equal to the clock rate divided by eighty (80).
BD14
RCVSEL
Selects high or low Receiver data rate. If RCVSEL = “0” then the received data rate should be equal to the clock
rate divided by ten (10), if RCVSEL = “1 “then the received data rate should be equal to the clock rate divided
by eighty (80).
BD15
WLSEL
Selects word length. If WLSEL = “0” a 32-bit word format will be selected. If WLSEL = “1” a 25-Bit word format
will be selected.
TABLE 1. ARINC 429 32-BIT DATA FORMAT
ARINC BIT #
FUNCTION
1 - 8
Label
9 - 10
SDl or Data
11
LSB
12 - 27
Data
28
MSB
29
Sign
30, 31
SSM
32
Parity Status
TABLE 2A. WORD 1 FORMAT
BI-DIRECTIONAL
BIT #
FUNCTION
ARINC BlT #
15, 14
Data
13, 12
13
LSB
11
12, 11
SDl or Data
10, 9
10, 9
SSM Status
31, 30
8
Parity Status
32
7 - 00
Label
1 - 8
HS-3282