33
Device options that may be specified are:
Option
Action
SC=<n>
Set the interface card select code; default is 11
Unit options that may be specified for the keyboard and printer are:
Option
Action
UC
Upshift lowercase characters to uppercase; default
7B
Transfer characters with the high-order bit cleared
7P
Transfer characters with the high-order bit cleared, non-printing suppressed
8B
Transfer characters without changing
AUTOLF
Enable automatic output of line-feed characters
NOAUTOLF
Disable automatic output of line-feed characters; default
The keyboard and printer may be set separately to one of four I/O modes (
UC
,
7B
,
7P
, or
8B
). The default mode is
UC
for both units.
Some HP software systems expect the console terminal to transmit line feed characters automatically following
each carriage return. As an aid to avoid typing LF characters after pressing ENTER, the
AUTOLF
option may be
specified for the keyboard unit. This simulates pressing the AUTO LF latching key on an HP 264x terminal.
The teleprinter interface state contains these registers:
Name
Size
Radix
Description
BUF
8
8
Output data buffer
MODE
16
8
Interface configuration mode
CTL
1
2
Control flip-flop
FLG
1
2
Flag flip-flop
FBF
1
2
Flag buffer flip-flop
KPOS
32
10
Number of characters input
KTIME
24
10
Keyboard polling interval
TPOS
32
10
Number of characters printed
TTIME
24
10
Time from I/O initiation to interrupt
PPOS
32
10
Position in the punch output file
4.2 12539C Time Base Generator
The HP 12539C Time Base Generator provides a programmable interval clock employed as the DOS, RTE, and
TSB time-of-day and process-switching clocks. The TBG provides programmable periods of 100 microseconds to
1000 seconds in decade increments. Each “tick” of the clock may request an interrupt, and a status indication is
provided if the TBG ticks a second time without acknowledgement.
