1575PCI Ver la hoja de datos (PDF) - Holt Integrated Circuits

Número de pieza

componentes Descripción

Lista de partido

1575PCI

3.3V Dual Transceivers with Integrated Encoder / Decoders

Holt Integrated Circuits 

HI-1575

The host reads the received word from the HI-1575 RXA or

RXB register. The data word is read by pulsing STRB low,

while R/W is high and REG is low. Figure 4 shows an

example receive operation. The SYNC output indicates

whether the word had a Command Sync (SYNC=1) or

Data Sync (SYNC=0). SAM register bits 8 and 12

(RSYNCA and RSYNCB) retain the Sync values for the

last word received on each bus.

SAM bits 2 or 3 (RENA, RENB) can be used to

independently enable or disable each receiver. Writing a

'1' to RENA enables receiver A. A '0' disables the receiver.

RENB performs the same function for the MIL-STD-1553

bus B.

Note that because each receiver is internally connected to

its transmitter, when a MIL-STD-1553 word is transmitted

by the HI-1575 it will also be received on the same

channel. This feature allows the terminal to self-monitor

data transmitted to the MIL-STD-1553 data bus.

MIL-STD-1553 BUS CONNECTION

The HI-1575 includes on-chip MIL-STD-1553 analog

transceivers which are designed to drive the primary

winding of a 1:2.5 turns-ratio MIL-STD-1553 isolation

transformer. Figure 6 shows how the HI-1575 may be

connected to the MIL-STD-1553 data bus as either a

direct coupled stub (Bus A example), or a transformer

coupled stub (Bus B example). Holt Integrated Circuits

offers a wide range of single-core and dual-core coupling

transformers suitable for use with the HI-1575.

12.0 MHz

Host CPU

3.3 V

VDD

CLK

STRB

BUSA

R/W

CHA/CHB

BUSA

REG

D15:D0

SYNC

HI-1575

RCVA

RCVB

ERROR

BUSB

MR

BUSB

GND

55 Ohms

1:2.5

55 Ohms

MIL-STD-1553

BUS A

(Direct Coupled)

1:2.5

52.5 Ohms

52.5 Ohms

1:1.4

MIL-STD-1553

BUS B

(Transformer Coupled)

FIGURE 6. MIL-STD-1553 BUS CONNECTION

Bit Period

Command Word

Data Word

Status Word

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

SYNC

TERMINAL ADDRESS R/T

SYNC

SUBADDRESS

/ MODE

DATA WORD

P

COUNT

SYNC

DATA WORD

P

SYNC

SYNC

TERMINAL ADDRESS ME

SYNC

CODE FOR FAILURE MODES

FIGURE 7. MIL-STD-1553 WORD FORMATS

HOLT INTEGRATED CIRCUITS

6

TF P

Share Link: