Eeprom Control Circuit; Sensor Circuit - Epson LQ-2180 Service Manual

LQ-2180

2.1.6 EEPROM Control Circuit

When the printer power is turned off, the EEPROM stores the factory
settings and values in the areas that are not cleared in the user setting
mode and also writes those values in the RAM. This sequence is
managed by the CPU (IC4), which transmits data in the serial format.
The EEPROM control circuit is as shown below:
C P U ( I C 4 )
9
P 7 0
1 0
P 7 1
1 1
P 7 2
1 2
P 7 3
Figure 2-7. EEPROM Control Circuit
Operating Principles
R e a r P E
S e n s o r
F r o n t P E
S e n s o r
A T 9 3 C 4 6 ( I C 5 )
1
C S
2
P W , T O P
S K
S e n s o r
3
D I
4
D O
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2.1.7 Sensor Circuit

Unlike the LQ-2170, both the CPU and the gate array monitor and
control the corresponding sensors' conditions. Note analog voltages are
all monitored by the CPU ports.
+ 5 V
C P U ( I C 4 )
+ 5 V
7 0
P 4 0
6 8
P 3 6
7 5
A N 2
G A ( I C 3 )
+ 5 V
+ 5 V
+ 5 V
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Control Circuit
+ 5 V
7 6
P 5 3
6 1
P 2 7
1 8
I N T 7
1 1 6
R e l e a s e 1
1 1 7
R e l e a s e 2
Figure 2-8. Sensor Circuit
Revision A
+ 5 V
H P S e n s o r
R e l e a s e
S e n s o r 2
R e l e a s e
S e n s o r 1
P G S e n s o r
C o v e r O p e n
S e n s o r
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