EM73866 Datasheet, PDF (22/39 Pages) ELAN Microelectronics Corp – 4-BIT MICRO-CONTROLLER FOR LCD PRODUCT

EM73866
4-BIT MICRO-CONTROLLER FOR LCD PRODUCT
Interrupt controller:
IL0-IL5
: Interrupt latch. Hold all interrupt requests from all interrupt sources. ILr can not be
set by program, but can be reset by program or system reset, so IL only can decide
which interrupt source can be accepted.
MASK0-MASK3
EI
: Except INT0 ,MASK register can promit or inhibit all interrupt sources.
: Enable interrupt Flip-Flop can promit or inhibit all interrupt sources, when inter-
rupt happened, EI is cleared to "0" automatically, after RTI instruction happened,
EI will be set to "1" again.
Priority checker: Check interrupt priority when multiple interrupts happened.
INTERRUPT FUNCTION
The procedure of interrupt operation:
1. Push PC and all flags to stack.
2. Set interrupt entry address into PC.
3. Set SF= 1.
4. Clear EI to inhibit other interrupts happened.
5. Clear the IL for which interrupt source has already be accepted.
6. To excute interrupt subrountine from the interrupt entry address.
7. CPU accept RTI, restore PC and flags from stack. Set EI to accept other interrupt requests.
PROGRAM EXAMPLE: To enable interrupt of "INT0, TRGA"
LDIA #1100B ;
EXAE
; set mask register "1100B"
EICIL 111111B ; enable interrupt F.F.
LCD DRIVER
EM73866 can directly drive the liquid crystal display (LCD) and has max. 32 segment and 4 common output pins.
There are total 32 x 4 dots can be display. The VRLC pin is the LCD driver power input, there is the voltage
of (V_CC-VRLC) to LCD.
CONTROL OF LCD DRIVER
The LCD driver control command register is P27. When LDC is 00, the LCD is disabled and changes the duty
only. When LDC is 01, the LCD is blanking, the COM pins are inactive and the SEG pins continuously output
the display data. When LDC is 11, the LCD driver enables, the power switch is turned on and it cannot off
forever except the CPU is reseted or sleeping. User must enable the LCD driver by self when the CPU is waked
up.
Port27
32
LDC
LDC
00
01
10
11
10
Initial value : 0000
DUTY
LCD display control
LCD display disable & change duty
Blanking
Reserved
LCD display enable
DUTY
00
01
10
11
Driving method select
1/4 duty (1/3 bias)
1/3 duty (1/3 bias)
1/2 duty (1/2 bias)
Static
Frame frequency
85 Hz
114 Hz
171 Hz
85 Hz
* This specification are subject to be changed without notice.
12.29.1999 ₂₂