Read Sharp ER-A880 (serv.man2) Service Manual online
4-3. Buzzer circuit
The I/O controller controls three kinds of buzzer sounds.
•
Short 1 shot buzzer (about 70 ms)
•
Long 1 shot buzzer (about 140ms)
•
Long buzzer (Keeps sounding until the buzzer OFF command is
executed.)
executed.)
4-4. MCR circuit
The I/O controller controls data in track 1 and track 2 of the MCR
(Magnetic Card Reader).
(Magnetic Card Reader).
4-5. Keyboard controller
<ER-A850>
<ER-A880>
Model
No. of Strobes
No. of returns
ER-A850
13
12
ER-A880
25
10
For recognition of KEY expansion, several input ports are used to
define each KEY expansion mode and to specify the KEY scan range.
define each KEY expansion mode and to specify the KEY scan range.
In the ER-A850/A880, setting is made as follows. MODE0 and
MODE1 mean mode terminals of I/O controller.
MODE1 mean mode terminals of I/O controller.
MODE1
MODE0
No. of strobe
×
No. of return
0 (LOW)
0 (LOW)
16
×
16 mode (ER-A850)
0 (LOW)
1 (HIGH)
32
×
16 mode (ER-A880)
1 (HIGH)
0 (LOW)
32
×
32 mode (Reserved)
1 (HIGH)
1 (HIGH)
32
×
32 mode (Reserved)
For scan control, the following scan modes are realized. The KTYP
terminal of I/O controller is used to set the scan mode.
terminal of I/O controller is used to set the scan mode.
Scan system
Model type
KTYP terminal
Touch panel mode
ER-A880
1 (HIGH)
Normal mode
ER-A850
0 (LOW)
1
Touch panel mode
The make/break control system is employed.
Even when two or more keys are pressed at a time, the make
code of the "made" key is sent to the host. When the key is
released, the break code is sent. (Max. 4 keys can be controlled at
a time.)
The make/break control system is employed.
Even when two or more keys are pressed at a time, the make
code of the "made" key is sent to the host. When the key is
released, the break code is sent. (Max. 4 keys can be controlled at
a time.)
2
Normal mode
In this normal keyboard control mode, double depression is inva-
lid.
In this normal keyboard control mode, double depression is inva-
lid.
4-6. Clerk key circuit
The clerk key is controlled by 6 bit.
4-7. WMF key circuit
I/O
controller
BUZ1
74LS00
DTC114YK
VCC
Buzzer
I/O
controller
INT1, INT2
MTS1, MTS2
CKA1, CKA2
74LS00
4069
RCP1, RCP2
CLS2
CLS1
RCD2
RCD1
ER-A8MR
MCR CN
I/O
connector
ST0~4
KST0~KST7
74LS138
74LS138
KST8~KST12
KR0~11
KKR0~KKR7
74HC244
74HC244
KKR8~KKR11
Key board
matrix
matrix
I/O
connector
ST0~4
KST0~KST7
74LS138
KST8~KST15
Key board
matrix
matrix
74LS138
KST16~KST23
74LS138
KST24
KR0~11
KKR0~KKR7
74HC244
KKR8~KKR9
74LS138
74HC244
ST0~4
74LS138
KST0~KST5
Clerk key
ST0~4
74LS244
PSC
CFSR
ST0~4
CFSR
74LS138
ST0~ST7
PSC
ST0~ST3
74LS125
ST4~ST7
X4~X7
74LS125
X0~X3
WHFCN
– 76 –
Click on the first or last page to see other ER-A880 (serv.man2) service manuals if exist.