Sharp MZ-5500 Tehnical Manual

C:J D --I-f3 -- F33B I I I I
[±]I-H+I
Fig. 11- 5
(B) Same keys are inaperative:
Cheeking key eontaets
Conneet the keyboard to the System Unit, and turn on the
system with the CTRL and ALG (a, c) keys depressed and
held . After making sure all the indicators . come on, press
the keys in the order shown by the arrows in the above
figure. If no defective key contact exists, all the indicators
will go off . If any defective contact exists, alt the indicators
will remain on. If a wrong key is pressed and the indicators
eome on, they will 90 off when the eorrect key is sub-
sequently pressed .
If no eontact trouble exists when alt the keys have been
operated , the CAPS indicator will come on, indicating that
the key cheek was normal.
11-3 Key search timing
Slngll klY op.'lIlon
I eNlllr i ng
. '\..W t ~ 1 I fIoL
II" f " ___ ---I
Boun ..
~
(11 11 !JA I A _____ _ ---4nL-_~;~1-_2_by_I .. _d._II ___ _ ___lL
Fig.11- b
To prevent ehattering and bounce, the same key data is
cheeked twice during each search, and only matching ' key
data is regarded as correct. While the search cycle is 5.5ms,
it is ex tended to 16.5ms if a bounce occurs ' ~
t\"YI~
~~-------
~~Y2
~ fwutH.
IlAlAI
_ __ _ ___
_ _ ----'
lJ l:'l I ~A JA ___ ___ fLJl~f.L_ ....... : ~~1 ----::=--::-:c;-:------
K~Y2 IJATA
Fig. 11-?
Key search sequence for two-key operation is th~ same as
that for single key operation. When two keys are simul-
taneously pressed, key data for the first and second keys
are successively
transferred.
11-4 Eight-bit keyboard processor J..IPD80C49
Highlights
1)
Single-chip, 8-bit microprocessor.
2) 6uilt-in 2K x 8 bit ROM.
3) On· chip 128K x 8 bit RAM.
4) Interruption service capability.
5) 1/0 port: 8 bits x 2
Oata bus (serving also as 1/0 port): 8 bits x 1
6) Built·in clock generator.
7) Single +2.5 to +6V power supply.
Pin configuration
TO
Vcc
XTALI
Tl
XTAU
1'27
RESET
1'26
SS
1'25
JNT
1'24
EA
Pl7
RD
PI6
PSEN
1'15
WR
1'14
ALE
PI3
DHO p 12
DDl
1'11
OH2
1'10
OD3
Voo
084
PROG
DH5
1'23
086
P22
DH7
1'21
Vss
20
21
1'20
Fig.l1-ß
Pin functions
Pl0 - P17:
1/0 port (port 1)
P20 · P27:
1/0 port (port 2)
OBO · 067:
Oata bus
TO, Tl:
Test
TFJT:
Interrupt
RO:
Read
WR: Write
ALE .
Address latch enable
PSEN:
Program store enable
RESET:
Reset
SS:
Single
step
EA: External access
XTAL1,2:
Ouartz inputs
VOO: Standby eon trol
t<

Sharp MZ-5500 Specifications

General

Brand	Sharp
Model	MZ-5500
Category	Desktop
Language	English