The printer attachment consists of a device
controller, a printer adapter, and a printer. Figure
6-9 illustrates the structure of the subsystem and
its relationship to the system.
The device controller is a microprogrammed
peripheral controller which attaches to the Level
6 Megabus and is capable of supporting up to 4
devices via a configurable series of adapters.
Device specific functionality is provided by the
adapter and certain device specific firmware in
the device controller.
the range and address of the buffer and the
specific types of operations to be performed. The
printer attachment can be set to interrupt after
each print line or it can be programmed in the
Level 6 software allows for the transfer of data
to the printer by a series of input/output pro
gramming commands. These commands and their
associated meanings are summarized in Table 6-2.
A detailed discussion of all the input/output
commands can be found in Series 60 (Level 6)
Minicomputer Handbook, Order No. AS22.
LEVEL 6 MEGABUS
Operator maintenance includes such preven
J __ -,
tive maintenance as normal checking, cleaning,
operating considerations, etc., performed periodi
cally on a routine scheduled basis. The purpose of
_ _ _ _ _ _
'- _ _ _ _ ---1
the maintenance is to keep the printer in the best
of operating conditions thereby reducing the pos
sibility of downtime.
The following list is a general guide to opera
o Always plug the printer into a 3-wire
o Ensure that all covers are closed and
secured during operation.
Figure 6-9. Serial Printer Attachment
o Never operate the printer without paper.
o Avoid leaning or placing objects on any
PROGRAMMING CONSIDERA nONS
part of the printer.
Level 6 software builds a data buffer in
memory for each line of print to be output. Input
o Turn power OFF before adjusting print
and Output commands are then issued to specify
head or replacing ribbon.
TABLE 6-2. INPUT/OUTPUT COMMAND SUMMARY
INPUT INTERRL'PT CONTROL
INPUT MEMORY BYTE ADDRESS
INPUT MEMORY MODULE ADDRESS
INPUT STATUS WORD ONE
INPUT STATUS WORD TWO
INPUT DEVICE ID
OUTPUT INTERRUPT CONTROL
OUTPUT ADDRESS AND RANGE