EM73PA88A
4-BIT MICRO-CONTROLLER FOR LCD PRODUCT
NOP
NOP
NOP
NOP
4 cycles
; READ DATA
INA
STA
NOP
P7
TEMP
; read D_ADR1
3 cycles
INA
P7
; read D_ADR1+1
MELODY (SOUND EFFECT) CONTROL
One channel melody/sound effect output, controlled by port 23, 24, 17, and 30.
There is a built-in sound effect. It includes the tone generator and random generator. The tone generator is a
binary down counter and the random generator is a 9-bit liner feedback shift register.
P30
P23,P24
f2
f1
Tone
generator
CLK/8
4 kinds
of divider
2
2
Output
control
f2x2
PWM / D/A ckt.
Random
generator
Sound effect command register (P30)
There are 4 kinds of basic frequency for sound generator which can be selected by P30. The output of sound
effect is tone and random combination.
Port30
3
2
1
0
BFREQ SMODE
Initial value : 0000
SMODE
BFREQ Basic frequency (f1) select
Sound generator mode
Disable
0
0
1
1
0
1
0
1
CLK/16
CLK/32
CLK/64
Reserved
0
0
1
1
0
1
0
1
Tone output
Random output
Tone+random output
(CLK=4.6MKz)
Tone frequency register (P23, P24)
The 8-bit tone frequency register is P24 and P23. The tone frequency will be changed when user output
the different data to P23. Thus, the data must be output to P24 before P23 when users want to change the 8-
bit tone frequency (TF).
Port24
Port23
3
2
1
0
3
2
1
0
Initial value : 1111 1111
Higher nibble register
Lower nibble register
** f1=CLK/2X, f2=f1/(TF+1)/2, TF=1~255, TF-0
** Example : CLK=4.6 MHz, BFREQ=10, TF=00110001B.
f1=143.75K Hz, f2=143.75K Hz/50/2=1430 Hz
* This specification are subject to be changed without notice.
10.8.2001
28
ELAN [ ELAN MICROELECTRONICS CORP ]
