LX-105O+
Service Manual Operating Principles
2.3.2.7
EEPROM
Circuit
The
EEPROM
stores in its memory the current feed position of continuously fed paper, as well as
the current panel settings. This memory is retained even after power is shut off.
EEPROM
can memorize the current position of continuously fed paper, so that this information can
be maintained even if power goes off.
Following figure shows the
EEPROM
circuit. Note that this is external to the CPU’s memory space.
EEPROM
is selected when CPU port
PC5
goes HIGH. Once
EEPROM
has been selected, the data to
be sent is set in CPU
Dort
PB1, and is fed bit-by-bit to the
EEPROM
in line with rising pulses from
CPU port PC4’S
clock:
Data are read,
bit-by-bitjin
line with falling clock pulses.
The
EEPROM
receives commands to indicate whether to read or write data,
addresses.
CPU
ER59256
K
PD78 10HG
( 1 c)
(2C)
DI
3
10
PB 1
DO
49
PBO
Cs
‘
22
T.
PC5
7
TEST
CLK
2
21 PC4
R1
19
RI 20
33K
33K
777
Figure 2-19. EEPROM Circuit-.
and to indicate
Rev.
A
2-15