U UNIVAC 1218 - Bitsavers

2.6.4 MAINTENANCE DATA TURNAROUND
CHANGE 2
The maintenance function provides a means for checking the linkage between
the master and the slave. Performance of this function does not involve any
slave peripheral device.
When using the maintenance turnaround, full cycles must be used; that is,
send data to slave and retrieve data from slave. Data will be returned to
the master in the same code as sent to slave. The maintenance turnaround
sequence is:
1) Send a message header and output buffer containing turnaround data to
the slaveg The MEFW should have a D field of O. The Message header
has a function code of 5.
2) Upon completion of output send a message header to the slave for input
of turnaround data. The D field of the MEFW = 0 and the function code
in the message header = 5.
3) Send a MEFW for input to return data to the master.
The output and input data transfer rules are found in Subsection 2.6.1 and
2.6.2.
2.7 ERROR NOTIFICATION
Peripheral or format errors and interface errors can occur with the slave
system. Subsection 2.4.2.2 describes the format errors. The sense byte of
the EISW presents interface errors to the master. If the slave is unable
to get the proper response from the ICCU, it comes to a stop and displays
'F3'. This indicates that the slave attempted recovery and failed. The
system should be cleared and restarted.
3. 9200/9300 / ICCU INTERFACE
3.1 INTRODUCTION
To avoid duplication one basic interface will be used for the 9200/9300 Computer
with the ICCU 18, 30, and 36-bit word lengths. The ratio between the
number of characters per computer word and the length of the message header,
creates a unique program for the 30-bit computer family. The only modification
required between various data formats is in the number of bytes accepted in
the header that is sent from the master computer.
Since the 9200/9300 / ICCU interface is dependent upon the military computer/
ICCU interface frequent reference will be made to Section 2.
The basic interface between a 9200/9300 Computer and the ICCl] shall be defined
as follows.
II-G-17