EM73461B Datasheet, PDF (16/40 Pages) ELAN Microelectronics Corp – 4-BIT MICRO-CONTROLLER FOR LCD PRODUCT

NORMAL OPERATION MODE
EM73461B
4-BIT MICRO-CONTROLLER FOR LCD PRODUCT
Preliminary
The 4-bit µc is in the NORMAL operation mode when the CPU is reseted. This mode is a dual clock system
(high-frequency(fc) and low-frequency(fs) clocks oscillating). It can be changed to SLOW or STOP
operation mode by the command register (P22 or P16).
The instruction cycle is 8/fc in NORMAL operation mode.
LCD display and high speed timer/counter with melody output are available for the NORMAL operation
mode.
SLOW OPERATION MODE
The SLOW operation mode is a single clock system (low-frequency(fs) clock oscillating). It can be changed
to the DUAL operation mode with the commoand register (P22), STOP operation mode with P16 and IDLE
operation mode with P19.
The instruction cycle is 4/fs or 8/fs by frequency double mask option in SLOW operation mode.
LCD display and high speed timer/counter with melody output are available for the SLOW operation mode.
P22 3 2 1 0
* SOM * *
Initial value : 0000
SOM
0
1
Select operation mode
NORMAL operation mode
SLOW operation mode
P14
32
10
Initial value : *000
* WKS LFS CPUS
LFS
Low-frequency status
CPUS CPU status
0
LXIN source is not stable
0
NORMAL operation mode
1
LXIN source is stable
1
SLOW operation mode
WKS
0
1
Wakeup status
Wakeup not by internal timer
Wakeup by internal timer
Port14 is the status register for CPU. P14.0 (CPU status) and P14.1 (Low-frequency status) are read-only
bits. p14.2 (wakeup status) will be set to "1" when CPU is wake-up by internal timer. P14.2 will be cleared
to "0" when user out data to P14.
IDLE OPERATION MODE
The IDLE operation mode suspends all SLOW operations except for the low-frequency clock and LCD
driver. It retains the internal status with low power consumption without stopping the clock function and
LCD display.
LCD display is available for the IDLE operation mode. Sound generator is disabled in this mode. The IDLE
operation mode will be wakeup and return to the SLOW operation mode by the internal timing generator or
I/O pins (P0(0..3)/WAKEUP 0..3 or P8(0..3)/WAKEUPA..D).
* This specification are subject to be changed without notice.
12.26.2001 ₁₆