Printer Interface - Sharp MZ-5600 Service Manual

-
M Z-5600
8-9-3. Internal block diagram
RAW DATA
IRS
81NCH I
MFM
M2R
M2C
CSPI
lORD
Ta.\R
RES
lAD
IAI
100
ID7
IR-PRT
I
Delay
circuit
Phase
PDL PDH PUL PUH
Cex 1
Gain change circuit
Cex 2
~
--
S-R
r-----
pulse
..
circuit
I-
Loop
f-
change
circuit
compare
circuit
Voltage
control
oscillator
I
I
I
I
T
t
r---I-----T--------
1
I .. ..
,....a..-_.....,. ....-----,
}-_+I-I GAP SYNC ID ...
I
I
I
reset - - count ---- separator
r------
}---:--I
circuit circuit circuit
I
I
VFO
SYNC
circuit
~
I
I
L
_S:'N~ d~e~ ~o~
_ _ _ _ _
_ _ _ _ _ _ .1
Q.NR
I
Divider
~
circuit
TPI
4
~~M
I
WIND
Decoder
RD DATA
I
I
L..-_ _ _ _ _ _ _ _ _ _ _ _ _ -{
- - {
- - 0 - -
il-
I
GND
M5C M5R
9. PRINTER INTERFACE
825PA
cs
pe5 ( > 0 - - - - - 0 S1IDBE
Rii
WR
PAD
DATAl-fi\TA8
RESET
PA7
AO
AI
PCS
PHD
1-----0<,
1--Nl~-oBUSY
PHI 1 - - - - o c : : u f - N l - - - - o P E
PCS
PH2 1----oc~f-Nl----OSELEcr
L -_ _ _ _ _ _ _ _
~
Do----oSRES
Fig. 48
-44-
9-' Logic description
The printer interface uses an integral parallel interface
controller, 8255. The 8255 has the modes shown in the
table at the right. Group A of the 8255 is used in Mode 1
for Centronics interface, so that the CPU may be inter-
rupted by an ACK signal from the printer by Mode 1
function.
Table
24
Mode 1
PAO
output
-
PA7
PC7
PC6 ACK
PC5 OUT
PC4
OUT
PC3 INT
Mode 0 PC2
output PC1 OUT
PCO
Mode 0 PBO
input
-
IN
PB7