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MAQ3693FD View Datasheet(PDF) - Dynex Semiconductor

Part NameDescriptionManufacturer
MAQ3693FD 1553B Bus Controller/Remote Terminal Dynex
Dynex Semiconductor Dynex
MAQ3693FD Datasheet PDF : 41 Pages
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MA3690/1/3
Four bits of the Instruction word (bits 10-7) define
conditions under which the terminal will generate an interrupt
to the subsystem (IRQN). Note that the generation of IRQN will
only take place after any selected retry conditions have been
exhausted.
The interrupt conditions which may be selected can be
categorised as follows:
1. Interrupt if no response - the terminal will generate an
interrupt if the RT does not respond.
2. Interrupt if Status bit set - the terminal will generate an
interrupt if a received status word has a bit set other
than in the RT address field or if the wrong RT
responds.
3. Interrupt Always - the terminal will generate an
interrupt regardless of whether the message was
successful or not.
4. Interrupt if word error - the terminal will generate an
interrupt if a word encoding or word count error
occurs.
Retry Count
The two most significant bits of the instruction word specify
the number of retries to be carried out when a retry condition
has been detected. (Maximun 3 given by code 11)
RECEIVE COMMAND WORD
The receive command word is addressed when CODENN
and C1 are both low and R/WN and C0 are both high. This
word is the command word which will be transmitted for a BC
to RT transfer or as the first command word of an RT to RT
transfer.
Note: This word should be set to 1111 HEX if the message
code is 000 or 100, or if the Function Code is not 00.
TRANSMIT COMMAND WORD
In all of the above cases, the terminal will generate a 250ns
pulse on IRQN and enter the halted state. This will occur after
the Report sequence has been executed.
Note the INCADRN will not be produced.
Retry Condition
Code Definition
The transmit command word is addressed when CODENN
and C0 are both low and R/WN and C1 are both high. This
word is the command word which will be transmitted for an RT
to BC transfer or as the second command word of an RT to RT
transfer.
Note: This word should be set to 1111 HEX if the message
code is 001 or 101, or if the Function Code is not 00.
001 Retry if error
010 Retry if status bit set
100 Retry if busy set
Three bits of the Instruction word (bits 13-11) are used as
flags to specify conditions under which the terminal will
execute automatic message retries until the retry number
count is zero. The retry flags are involved with the following
conditions:
1. Retry if error - this includes a no-status response, a
word encoding error, or a wrong word count from a
responding RT.
2. Retry if Status bit set - an automatic retry will take
place if a received status word has a bit set, other
than in the RT address field, or if the wrong RT
responds.
3. Retry if Busy - this is a specific check for the setting of
the Busy bit in a responding RT’s status word.
DATA POINTER WORD
The data pointer word is addressed when CODENN is low
and C0, C1 and R/WN are all high. This word is intended as a
base address pointer to the subsystem data store thus
specifying where any data words associated with the current
instruction should be stored or retrieved from. As such, this
word is not read into the terminal itself but is merely transferred
from the Instruction Store to a suitable external address latch.
(The BUFENN signal is therefore inactive during this transfer).
The remaining two bits of the Instruction word specify the
number of message retries which the Bus Controller will
attempt automatically. A code of 00 specifies no retries, a code
of 11 specifies the maximum of three retries. The retries are in
addition to the initial message transmitted, hence a message
may be transmitted four times in total, if not successful. Note
that if the condition which is being tested becomes invalid, the
retry sequence will discontinue on the next message with the
Bus Controller completing execution of the message in the
relevant manner.
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