DSIT

Define Status Interrupt

DSIT

Opcode:

13

00010011

Synopsis

DSIT specifies the bit mask used with the STATUS[0] and STATUS[1] byte to generate an

interrupt IT4 to controller. Each time a bit change happens in the status words, assuming

the corresponding bit mask will be set, an interrupt will be generated.

Parameters

Field

Byte

Pos.

Value

Definition

STA_IT_MSK0

1

7..0

Status[0] bit mask pattern

STA_IT_MSK1

2

7..0

Status[1] bit mask pattern

Notes :

The default IT Status is 0x3F for STATUS[0] and 0xFF for STATUS[1].

FORM

Select Transmission Format

FORM

Opcode:

09

00001001

Synopsis

FORM defines the type of transmission used. This format is valid only in the parallel data

mode. The default format, unless specified, is synchronous.

Parameters

Field

Byte

Pos.

Value

Definition

X_SYNC

1

1..0

00*

01

10

11

Synchronous format

Transmit continous ”1”

(1)

HDLC framing

Transmit continous ”0”

(1)

Notes :

1. This format is only valid for the transmiter.

HSHK

Handshake

HSHK

Opcode:

04

00000100

Synopsis

HSHK is used to command the ST75C520 to begin the transmit handshake sequence

processing. The progress of the handshake is reported to the control processor.

Parameter

Non parametric command.

IDT

Identify

IDT

Opcode:

14

00010100

Synopsis

IDT Return the ST75C520 Hardware and Software release number. See paragraph VII.1.4.

Parameter

Non parametric command.

INIT

Initialization

INIT

Opcode:

06

00000110

Synopsis

INIT forces the ST75C520 to reset all parameters to their default conditions and restart

operations.

Parameter

Non parametric command.

Notes :

This command makes a software reset of the ST75C520 and so cannot have the regular handshake protocol. It does

not increment the COMACK, neither generate an Interrupt.

ST75C520

21/45