Parallel Printer Controller Interface Timing; Parallel Printer Controller Instruction Sequence - NEC Advanced Personal Computer System Reference Manual

rrocessor reB
2-36
Table 2-9 Parallel Printer Controller Instruction Sequence
INSTRUCTION
Write Signal 0
Write Signal 1
Write Signal 2
(Not used for
Centronics I1F)
Write Signal 3
Write Signal 4
Write Signal 5
Read Signal
Write Data
RECEIVE DATA
DATA
DATA STB
BUSY LOW
INPUT BUSY
ACK
,
, I
,
,
I ,
+-
I..,
T4
DESCRIPTION
Set the 8255 Mode
Interrupt Enable Flag (lNTE)
Receive Machine Set (RMS)
Mask Set or Reset
1: Reset
0: Set
Input Prime (lP) Set or Reset
IP and Mask Set or Reset
Read the status of the printer
Write data to be printed
TS
I :
, I
I
I
I I ...
'
......
'
.....
~
T6 T4
1: Flag On
0: Flag Off
1: RMS On
0: RMS Off
1: Reset
0: Set
Tl TO T3 = 1
iJ.s MIN
T4
=
100 ns MAX
TS
=
0.1 TO 0.5
ms
T6
=
6 TO 8
iJ.S
Figure 2-22 Parallel Printer Controller Interface Timing