GMS81504 Datasheet, PDF (35/54 Pages) List of Unclassifed Manufacturers – CMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

HYUNDAI MicroElectronics
GMS81504
BUZZER FUNCTION
The buzzer driver consists of 6-bit binary counter, the
buzzer register BUR and the clock selector. It gener-
ates square-wave which is very wide range frequency
(250 Hz~125 kHz at fXIN=4 MHz) by user program-
mable counter.
Pin R55 is assigned for output port of Buzzer driver by
setting the bit 5 of PMR5 (address D1H) to "1". At this
time, the pin R55 must be defined as output mode (the
bit 5 of R5DD=1). In the emulator, even if pin R55 is
defined as input, buzzer output is available.
The bit 0 to 5 of BUR determines output frequency for
buzzer sound.
Frequency calculation is following below.
fBUZ (Hz)
=
2 ⋅ Prescaler
fXIN
ratio ⋅ BUR value
fBUZ: Buzzer frequency
fXIN: Oscillator frequency
Prescaler: Prescaler divide ratio by BUCK1, BUCK0
BUR:Lower 6-bit of BUR. Buzzer period data value
The bits BUCK1, BUCK0 of BUR selects the source
XIN PIN
÷ 16
÷ 32
÷ 64
÷ 128
MUX
COUNTER
(6 BIT)
PRESCALER
F/F
BUR[7:6]
BUR[5:0]
(6 BIT)
BUZ PIN
BUR REGISTER
Figure 23. Buzzer Driver
clock from prescaler output.
The 6-bit buzzer counter is cleared and start the count-
ing by writing signal to the register BUR. It is incre-
ment from 00H until it matches 6-bit register BUR.
Caution:
The register BUR contains undefined value after
reset. It must be initialized with 1H~3FH (none 0H).
BUR
MSB
LSB
BUCK1 BUCK0 BU5 BU4 BU3 BU2 BU1 BU0
ADDRESS: ECH
RESET VALUE: Undefined
Prescaler ratio
00: fXIN ÷ 16
01: fXIN ÷ 32
10: fXIN ÷ 64
11: fXIN ÷ 128
6-bit BUR value
Figure 24. BUR: Buzzer Period Data Register
MSB
LSB
PMR5
-
- BUZS -
-
-
ADDRESS: D1H
-
-
RESET VALUE: --0-----
R55/ BUZ Port Selection
0: R55
1: BUZ
Figure 25. PMR5: Port 5 Mode Register
35