November, 99
All Rights Reserved
17
B-443 Bar Code Printer
Service Manual
3.3 Reset Circuit
OUT
1
VCC
2
GND
3
U2
S-807
C2
0.1u
C47
0.1uF
VCC
RESET
Fig. 3.3 Reset Circuit
This is the reset circuit .The 80746ALO IC outputs the system reset signal of “ LOW” when the
driving voltage is lower than 4.6V (Typical).
3.4 Memory System
VCC
1
DQ0
2
DQ1
3
DQ2
4
DQ3
5
VCC
6
DQ4
7
DQ5
8
DQ6
9
DQ7
1 0
NC
1 1
NC
1 2
W
1 3
RAS
1 4
NC/A11
1 5
NC/A10
1 6
A0
1 7
A1
1 8
A2
1 9
A3
2 0
VCC
21
GND
22
A4
2 3
A5
2 4
A6
2 5
A7
2 6
A8
2 7
A9
2 8
OE
2 9
UCAS
3 0
LCAS
3 1
NC
3 2
DQ8
3 3
DQ9
3 4
DQ10
3 5
DQ11
3 6
GND
37
DQ12
3 8
DQ13
3 9
DQ14
4 0
DQ15
4 1
GND
42
U 1 5
T M S 4 1 6 1 6 0 P
/RAS
DRAMWR
A 1 8
1
A 1 6
2
A 1 5
3
A 1 2
4
A7
5
A6
6
A5
7
A4
8
A3
9
A2
1 0
A1
1 1
A0
1 2
AD0
1 3
AD1
1 4
AD2
1 5
GND
1 6
AD3
1 7
AD4
1 8
AD5
1 9
AD6
2 0
AD7
2 1
CE
2 2
A 1 0
2 3
OE
2 4
A 1 1
2 5
A9
2 6
A8
2 7
A 1 3
2 8
A 1 4
2 9
A 1 7
3 0
W E
3 1
VCC
3 2
U 1 6
29C040
A[8..23]
MA[0..9]
DO[0..7]
M A 0
M A 1
M A 2
M A 3
M A 4
M A 5
M A 6
M A 7
M A 8
M A 9
DO0
DO1
DO2
DO3
DO4
DO5
DO6
DO7
A8
A9
A 1 0
A 1 1
A 1 2
A 1 3
A 1 4
A 1 5
A 1 6
A 1 7
A 1 8
DO0
DO1
DO2
DO3
DO4
DO5
DO6
DO7
/OE
DRAMOE
ROM1
M A 0
M A 1
M A 2
M A 3
M A 4
M A 5
M A 6
M A 7
DO0
DO1
DO2
DO3
DO4
DO5
DO6
DO7
/LCAS
/UCAS
R/W
VCC
VCC
DO[0..7]
MA[0..9]
A[8..23]
A 1 8
1
A 1 6
2
A 1 5
3
A 1 2
4
A7
5
A6
6
A5
7
A4
8
A3
9
A2
1 0
A1
1 1
A0
1 2
AD0
1 3
AD1
1 4
AD2
1 5
GND
1 6
AD3
1 7
AD4
1 8
AD5
1 9
AD6
2 0
AD7
2 1
CE
2 2
A 1 0
2 3
OE
2 4
A 1 1
2 5
A9
2 6
A8
2 7
A 1 3
2 8
A 1 4
2 9
A 1 7
3 0
W E
3 1
VCC
3 2
U 2 5
29C040
VCC
ROM2
A8
A9
A 1 0
A 1 1
A 1 2
A 1 3
A 1 4
A 1 5
A 1 6
A 1 7
A 1 8
M A 0
M A 1
M A 2
M A 3
M A 4
M A 5
M A 6
M A 7
DO0
DO1
DO2
DO3
DO4
DO5
DO6
DO7
A 1 9
1
A 1 8
2
A 1 7
3
A 1 6
4
A 1 5
5
A 1 4
6
A 1 3
7
A 1 2
8
CE
9
VCC
1 0
NC
1 1
RESET
12
A 1 1
1 3
A 1 0
1 4
A9
1 5
A8
1 6
A7
1 7
A6
1 8
A5
1 9
A4
2 0
A3
2 1
A2
2 2
A1
2 3
A0
2 4
DO0
2 5
DO1
2 6
DO2
2 7
DO3
2 8
GND
2 9
GND
3 0
VCC
3 1
DO4
3 2
DO5
3 3
DO6
3 4
DO7
3 5
RDY
3 6
OE
3 7
W E
3 8
NC
3 9
NC
4 0
U 2 6
49F080(TSOP)
A8
A9
A 1 0
A 1 1
A 1 2
A 1 3
A 1 4
A 1 5
A 1 6
A 1 7
A 1 8
M A 0
M A 1
M A 2
M A 3
M A 4
M A 5
M A 6
M A 7
DO0
DO1
DO2
DO3
DO4
DO5
DO6
DO7
ROM3
VCC
/RESET
A 1 9
OPTIONAL FLASH ROM
Fig. 3.4 FLASH ROMS and DRAM Diagram
This is the memory circuit. The U16&U17 type 512K Byte FLASH ROM,U26 type 1M Byte
FLASH ROM and U15 type 2M Byte DRAM are used. The MCU R/W pin becomes “ H” when
reading Flash ROM or DRAM, and “ L” when writing.
Summary of Contents for B-443
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