GMS82524 Datasheet, PDF (48/93 Pages) Hynix Semiconductor – 8-BIT SINGLE-CHIP MICROCONTROLLERS

HYUNDAI MicroElectronics
GMS82512/16/24
13. BUZZER FUNCTION
The buzzer driver block consists of 6-bit binary counter,
buzzer register, and clock source selector. It generates
square-wave which has very wide range frequency (500Hz
~ 250kHz at f_XIN= 8MHz) by user software.
A 50% duty pulse can be output to R55/BUZ pin to use for
piezo-electric buzzer drive. Pin R55 is assigned for output port
of Buzzer driver by setting the bit 5 of PMR5 (address D1_H) to
“1”. At this time, the pin R55 must be defined as output
mode (the bit 5 of R5DD=1).
Example: 2.4kHz output at 8MHz.
LDM R5DD,#XX1X_XXXXB
LDM BUR,#9AH
LDM PMR5,#XX1X_XXXXB
X means don’t care
The bit 0 to 5 of BUR determines output frequency for
buzzer driving.
Equation of frequency calculation is shown below.
f_BUZ
=
--------------------------^f--^X---^I---^N---------------------------
2 × DivideRatio × BUR
f_BUZ: Buzzer frequency
f_XIN: Oscillator frequency
Divide Ratio: Prescaler divide ratio by BUCK[1:0]
BUR: Lower 6-bit value of BUR. Buzzer period value.
The frequency of output signal is controlled by the buzzer
control register BUR.The bit 0 to bit 5 of BUR determine
output frequency for buzzer driving.
XIN PIN
÷16
00
÷32
01
÷64 ₁₀
÷128 ₁₁
MUX
2
6-bit binary
R55 port data
6-BIT COUNTER
÷2
F/F
Comparator
Compare data
[0EC_H]
6
BUR
Internal bus line
0
1
R55/BUZ PIN
PMR5 Port selection
[0D1_H]
Figure 13-1 Block Diagram of Buzzer Driver
WW
ADDRESS: 0D1_H
RESET VALUE: --00 ----_B
PMR5 - -
- -- -
R54/WDTO Selection
0: R54
1: WDTO (Output)
R55/BUZ Selection
0: R55 port (Turn off buzzer)
1: BUZ port (Turn on buzzer)
BUR
W WW
BUCK1 BUCK0
ADDRESS: 0EC_H
RESET VALUE: Undefined
W W WW W
BUR[5:0]
Buzzer Period Data
Source clock select
00: ÷16
01: ÷ 32
10: ÷ 64
11: ÷128
Figure 13-2 PMR5 and Buzzer Register
FEB. 2000 Ver 1.00
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