Samsung SCX-5315F Service Manual page 134

Circuit Description
3-2-4 PROGRAM ROM (FLASH MEMORY) CONTROL
1) DEVICE
TYPE No.
CAPACITY
2) PROGRAMMING
BEFORE ASS'Y
AFTER ASS'Y
3) OPERATING PRINCIPLE
When the RCSO(ROM CHIP SELECT)signal is activated from the CPU after the POWER is ON, it acti-
vates RD SIGNAL and reads the DATA(HIGH/LOW) stored in the FLASH MEMORY to control the overall sys-
tem. The FLASH MEMORY may also write. When turning the power on, press and hold the key(power
switch) for 2 - 3 seconds, then the LED will scroll and the PROGRAM DOWNLOAD MODE will be activated.
In this mode, you can download the program through the parallel port.
AC CHARACTERISTICS
Addresses
CE#
OE#
WE#
Data
RY/BY#
t
VCS
V
CC
Notes:
1. PA = program address, PD = program data, D
2. Illustration shows device in word mode.
Note: Refer to the Erase/Program Operations table for t
3-14
AM29LV160DB
4 MBYTE (1MB * 16BITS * 2)
EPROM PROGRAMMER or PROGRAMMING at the factory
DOWNLOAD from PC
Program Command Sequence (last two cycles)
t
t
AS
WC
555h P A
t
CH
t
WP
t
WPH
t
CS
t
DS
t
DH
A0h
is the true data at the program address.
OUT
Figure 17. Program Operation Timings
CE#
WE#
BYTE
t
SET
(t )
AS
and t
AS
Figure 16. BYTE# Timings for Write Operations
- This Document can not be used without Samsung's authorization -
Read Status Data (last two cycles)
P A
t
AH
t
WHWH1
PD
Status
t
BUSY
The falling edge of the last WE# signal
t (t )
HOLD AH
specifications.
AH
P A
D
OUT
t
RB
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