Eeprom Control Circuit; Sensor Circuit - Epson Stylus PHOTO 1270 Service Manual

EPSON Stylus Photo 870/1270

2.2.2.5 EEPROM Control Circuit

Since EEPROM is a nonvolatile memory, it keeps information written if
the printer power is turned off. It stores such information as adjustment
values, factory values, and printer status values.
The EEPROM control circuit block diagram is as shown below:
+5V
93C56
(IC7)
8
Vcc CS
6
SK
ORG
5
GND DI
DO
Figure 2-21. EEPROM Circuit Block Diagram
EEPROM is connected to ASIC with 4 lines and each line has the following
function.
!
CS: Chip selection signal
!
CK: Data synchronism clock pulse
!
DI: Data writing line (serial data) at power off.
!
DO: Data reading line (serial data) at power on.
OPERATING PRINCIPLES
E05B70CD
(IC8)
1 206
EECS
2 205
EECK
204
3
EECO
203
4
EECI
Electrical Circuit Operating Principles

2.2.2.6 Sensor Circuit

The Stylus Photo 870/1270 has the following five sensors to detect
printer's status.
!
PE Sensor
!
ASF Sensor
!
BCO (Black head cartridge) sensor
!
CCO (Color head cartridge) sensor
!
Head Thermistor sensor
!
Liner sensor
The block diagram for the sensor circuit is as shown below:
SWA1
IC20 CPU IC8 AISC
DATA Bath
C90A11CA E05B70CD
SWA2
CRPHAA
CRENBA
CRAI0
CRAI1
AN0
SWC0
SWC1
Figure 2-22. Sensor Circuit Block Diagram
Revision B
CN5
+5v
PE Sensor
R57
200
PRV
C89
GND
C90
PE
+5v CN6
ASF Sensor
R93
200
ASFV
C93
GND
C94
ASF
CN12
PF Motor Encoder Sensor
ENA
ENB
CN8
CR Motor Encolder Sensor
ENA
ENB
CN9
I/C Detection Sensor & Thermistor
COB
COC
THM
53