Chapter 3
Transmit Mode
DAS-429PCI/Mx: User’s Manual
page 3 - 7
1
st
word in
instruction
block
The Word Count is used to specify the number of 32 bit ARINC-429 Data Words
in this instruction block (1 – 65535).
The Interword delay is used to set the delay (4 - 65504) between words in the
block and between the final word in this block and the first word in the following
block. Its resolution is 1 bit time. For high speed this gives it a range of 40
microseconds (interword value 4) to just over 655 milliseconds (interword value
65504). For low speed the range is 320 microseconds (interword value 4) to over 5
seconds (interword value 65504).
Note:
The ARINC-429 specification does not allow interword times less than 4
bit times, so interword delay values of less than 4 will be interpreted as
the minimum legal interword time.
The Transmit Data Pointer register is used to set the start address of the
transmit data buffer. The address must be a word boundary. The size of the
buffer is determined by the Word Count value.
3.3.1
Control Word Definition
Bit
Bit Name
Description
01-15
Reserved
0
00
Parity Error
0 = Normal Odd Parity (Standard
ARINC-429 parity)
1 = Even Parity (Error Injection)
Control Word Definition
3.3.2
Word Count
3.3.3
Interword Delay
3.3.4
Transmit Data Pointer
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