MAS3690FD datasheet(13/41 Pages) DYNEX

13 / 41 page

MA3690/1/3

13/41

Figure 5: Subsystem Status Latch

Figure 6: Remote Terminal Subsystem Interface Signal Transfer

SSERR - A low will cause the Subsystem flag to be set in the

terminal status word.

SERVREQ - A low will set the service request bit of the

terminal status word.

ILLEGAL COMMAND - Allows the subsystem to declare any

command word illegal. When low the terminal will inhibit data

transfers to or from the subsystem, and after message

validation will respond with the message error bit set in the

terminal status word.

ALLOW CODE - Provides the subsystem with the capability

to declare any of the reserved mode codes as being

meaningful. If a reserved mode code is received when high

the command is treated as illegal and after message

validation responds with ME bit set in the terminal status

word. If low the most significant bit of the mode code and the

T/R bit determine whether any data words are involved and

their direction.

RES0, RES1, RES2 - Provides the subsystem the capability

of setting any of the currently reserved bits of the terminal

status word.

DBACC - Dynamic Bus Acceptance. If low then the Dynamic

Acceptance bit of the terminal status word will be set in

response to a legal Mode Command for Dynamic Bus Control

allocation. After switching to the BC mode of operation the

first instruction must be a NOOP.

DBCACC

SSERR

SERVREQ

ILLEGAL COMMANDS

ALLOW CODE

RES0

RES1

RES2

TRANSPARENT

LATCH

STATENN

INCMDN

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