HMS87C13042A Datasheet, PDF (53/88 Pages) Hynix Semiconductor – 8-BIT SINGLE-CHIP MICROCONTROLLERS

HMS87C130XA/120XA/110XA
13. BUZZER OUTPUT FUNCTION
The buzzer driver consists of 6-bit binary counter, the
buzzer register BUR and the clock selector. It generates
square-wave which is very wide range frequency (480
Hz~250 KHz at f_XIN = 4 MHz) by user programmable
counter.
Pin RB1 is assigned for output port of Buzzer driver by set-
ting the bit BUZO of RBFUNC to “1”.
The 6-bit buzzer counter is cleared and start the counting
by writing signal to the register BUR. It is increased from
00H until it matches 6-bit register BUR.
Also, it is cleared by counter overflow and count up to out-
put the square wave pulse of duty 50%.
The bit 0 to 5 of BUR determines output frequency for
buzzer driving. Frequency calculation is following as
shown below.
f_BUZ(Hz)
=
---------------O----s--c---i--l-l--a---t-o---r----F---r--e---q---u---e---n---c--y----------------
2 × Prescaler Ratio × (BUR + 1)
The bits BUCK1, BUCK0 of BUR selects the source clock
from prescaler output.
BUR
BUCK1 BUCK0 BUR5 BUR4 BUR3 BUR2 BUR1 BUR0
Input clock selection
00 : f_XIN ÷ 8
01 : fXIN ÷ 16
10 : f_XIN ÷ 32
11 : fXIN ÷ 64
Buzzer Period Data
ADDRESS : DEH
RESET VALUE : 11111111
Bit Manipulation Not Available
÷8
÷ 16
f_XIN
÷ 32
MUX
÷ 64
BUCK[1:0]
COUNTER (6-bit)
BUR (6-bit)
F/F
COMPARATOR
BUZO
[RBFUNC.1]
RB1/BUZ PIN
Figure 13-1 Buzzer Driver
50
Apr. 2001 ver 1.0