Control Data 1700 Maintenance Manual page 42

SELECT END OF OPERATION INTERRUPT
A teletypewriter Select End of Operation Interrupt function is indicated by bit
03 of the Function Code being a logical "1". This bit enters the TTY controller
at 17-C13-6. If a Function command (13-B19-28) and the Equipment 1, Station 1
signal (13-B19-6) are also present, AND gate
(£)
(Z14 module, page 17) will be
satisfied. This causes the End of Operation Interrupt Enable FF to set. This
will interrupt the computer at effectively the time the controller goes into a
Not Busy status.
SELECT ALARM INTERRUPT
A teletypewriter Select Alarm Interrupt function is indicated by bit 04 of the
function code being a logical "1". This bit enters the TTY controller at
17-C13-22. If a Function command (13-B19-28) and the Equipment 1, Station 1
signal (13-B19-6) are also present, AND gate
~
(Z14 module, page 17) will be
satisfied. This will cause the Alarm Interrupt Enable FF to set. With this FF
set, any condition which generates an Alarm status (Ready
+
Lost Data) will cause
an interrupt to be sent to the computer.
SELECT WRITE MODE
Due to its close relationship with Data Write operations, the Select Write Mode
discussion is postponed until the Data Write topic. This will provide you
with a better understanding of the TTY controller status just prior to data
transfer in the Write Mode.
SELECT READ MODE
Due to its necessity in preparing for Data Read operations, the Select Read
Mode discussion is postponed until the Data Read topic.
2-15