MAS3690FD View Datasheet(PDF) - Dynex Semiconductor

Part Name

Description

Manufacturer

MAS3690FD

1553B Bus Controller/Remote Terminal

Dynex Semiconductor 

MA3690/1/3

CONTINUOUS OPERATION

The continuous message table

operation mode can be achieved by

ensuring that at the end of a message the

HALTREQN line is high. Thus, assuming

that the message has executed correctly,

the terminal will generate a signal to

increment the external address counter

(INCADRN) and continue to the next

instruction. If, however there has been an

interrupt generated (IRQN active) the

terminal will halt in the HALTEDN state

until specifically requested to continue.

Note that no address increment will take

place. To continue execution the

HALTREQN line should be taken low to

high for the appropriate time.

Continuous table driven operation

results in an intermessage gap of 20us.

Figure 1 shows the instruction fetch

and execute cycle.

Has

HALTREQ NO

gone low to

high ?

YES

Set HALTED high

Fetch Instruction

Message

Command

Error ?

YES

NO

Execute

Instruction

Retry

YES

Count = 0 ?

NO

Decrement

Retry Count

Pulse IRQ

YES

Retry

Required ?

NO

Output

Report Word

YES

INT.

Required ?

NO

Increment

Instruction Address

SET HALTED low

YES

NO

HALTREQ

=0?

Figure 1: BC Instruction Fetch and Execute Cycle

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