HI-3200PCTF View Datasheet(PDF) - Holt Integrated Circuits
Part Name
Description
MFG CO.
'HI-3200PCTF' PDF : 59 Pages View PDF
HI-3200, HI-3201
ARINC 429 Received Data Log FIFO
A 1K x 8 block of memory located between 0x3000 and
0x33FF is reserved for a set of eight ARINC 429 received
data FIFOs. There is one FIFO for each ARINC 429
received data channel. Each FIFO can hold up to 32 ARINC
429 32-bit messages.
A look-up table driven filter defines which ARINC 429
messages are stored in each FIFO. The look-up table is
pre-loaded with a “1” for each bit position corresponding to
a selected channel / label combination. The look-up table is
located at memory address 0x7A00.
When a new ARINC 429 message is received that meets
the programmed conditions for acceptance (Enable look-
up table bit = “1”), it is written into the channel’s Receive
Data FIFO. The contents of the FIFO may be read by the
host CPU using dedicated FIFO read SPI Instructions.
The status of each channel’s FIFOs is monitored by three
FIFO status registers: FIFO NOT EMPTY, FIFO
THRESHOLD, and FIFO FULL. One bit of each register
reflects the current status of each FIFO.
The FIFOs are empty following Reset. All three status
registers are cleared. When an ARINC 429 message is
written to a FIFO, its FIFO NOT EMPTY bit is set to a “1”.
When the FIFO contains more than the user-defined
number of messages as programmed in the ARINC FIFO
THRESHOLD VALUE register, its FIFO THRESHOLD bit is
set. If the FIFO is allowed to accumulate 32 messages, its
FIFO FULL bit is set. Once a FIFO is full, subsequent
messages continue to be written to the FIFO, and the oldest
message is lost.
The user may generate an Interrupt by enabling one of the
three FIFO status register bits to assert the FLAG bit in the
Pending Interrupt Register. ARINC 429 Control Register
bits 1:0 select the condition to trigger the FLAG interrupt.
The FIFO feature is particularly useful if the application
wishes to accumulate sequential ARINC 429 messages of
the same label value before reading them. The regular
ARINC 429 receive data memory will, of course, overwrite
messages of the same label value if a new message is
received before the host CPU extracts the data.
ARINC 429 Received Data Enable Look-Up Table
0x7AFF
0x7AE0
Filter Look-Up Table
Channel 7
Label = 0xFF
Label = 0xF8
0x7A3F
0x7A20
0x7A1F
0x7A00
Filter-Look-Up Table
Channel 1
Filter Look-Up Table
Channel 0
Label = 0x0F
Label = 0x07
Label = 0x08
76543210
Label = 0x00
Label = 0x01
ARINC 429 Received Data FIFO (x8)
ARINC 429
received
message
Data read by
Host CPU
SPI Instruction
0 - 32 Messages (32-bits)
FIFO NOT EMPTY
FIFO THRESHOLD
FIFO FULL
ARXCn <1:0>
A FNEn
AFHFn
A FFn
Select
From
Other
Channels
FLAGn
OR
PIR
FLAG
HOLT INTEGRATED CIRCUITS
18
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