Service manual

--
CE-1600E
(3) Signal Timing Chart
Moment when the power is turned on or when the reset button is
pressed (except when @ffi is pressed after an auto-power off.)
(4) Electrical Requirements
1.
Signal Levels
Input signal: TTL level
Output signal: TTL level (capable of driving one TTL IC)
1/0
-1
EXPRM t--Tt--I
2.
Input signal:
V
cc
DATA1- .... _ x:---x
DATA8~~-
STROBE Tl: approx. 20ms
T2: 1.5ms or more
T3: 1.5ms or more
T4: 15-20 µ.s
Output signal:
2.8K
M54514AP
or equivalent
Since all the outputs are through an open-collector, a pull-up resistor
(approx. 1kn - 10kn) at the printer is required. SHARP
recommended printers al ready include a pull-up resistor.
8. Block diagram
Centronics interface
PC-l600
v« __ ---!
v
rc
ir
PC-l600 '-- __ ..J
power supply circuit
EA-l60
(AC adapter)
AAx5
(SUM3x5)
CE-I600F
(2.5"FDD)
11!Q
,--- 1 ...
PTI .PUI .EZI
MINI.IORQ
MRQI.RDNI
WRNI
I'BO-7N
NU
RSTI--~----4_------~--~
Bu
: 8 bits
1/0 Buffer
I'CO-7N
Mu
: Mul t iplexer
FFl-3
: 8 bi ts Latch
DCl-3
Decorder
INT
: Interrupt circuit
RST
: Reset cireuit
PAO-7I
: 8 bi ts input
PBO-7N : 8 bi ts output port
PC 0-7 N : 8 bi ts output port
~-----
,
- -----,-- - - -- - - - - - - . - - -f - -f - .,
CSNO
107N RSTN
GNU vcc
[Fig.2) LR38045 block diagram gate array