Service manual

Circuit Description
3-14
3-2-4 PROGRAM ROM (FLASH MEMORY) CONTROL
1) DEVICE
2) PROGRAMMING
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
TYPE No. AM29LU160DB
CAPACITY 4 MBYTE (1MB * 16BITS * 2)
BEFORE ASS’Y EPROM PROGRAMMER or PROGRAMMING at the factory
AFTER ASS’Y DOWNLOAD from PC
Notes:
1. PA = program address, PD = program data, D
OUT
is the true data at the program address.
2. Illustration shows device in word mode.
Figure 17. Program Operation Timings
Note: Refer to the Erase/Program Operations table for t
AS
and t
AH
specifications.
Figure 16. BYTE# Timings for Write Operations
OE#
WE#
CE#
V
CC
Data
Addresses
t
DS
t
AH
t
DH
t
WP
PD
t
WHWH1
t
WC
t
AS
t
WPH
t
VCS
555h
PA PA
Read Status Data (last two cycles)
A0h
t
CS
Status
D
OUT
Program Command Sequence (last two cycles)
RY/BY#
t
RB
t
BUSY
t
CH
PA
CE#
WE#
BYTE
The falling edge of the last WE# signal
t
HOLD
(t
AH
)
t
SET
(t
AS
)