MC80F0804D View Datasheet(PDF) - Unspecified
Part Name
Description
Manufacturer
MC80F0804D Datasheet PDF : 120 Pages
| |||
MC80F0704/0708/0804/0808
16. BUZZER FUNCTION
The buzzer driver block consists of 6-bit binary counter, buzzer
register BUZR, and clock source selector. It generates square-
wave which has very wide range frequency (488Hz ~ 250kHz at
fXIN= 4MHz) by user software.
A 50% duty pulse can be output to R12 / BUZO pin to use for pi-
ezo-electric buzzer drive. Pin R12 is assigned for output port of
Buzzer driver by setting the bit 2 of PSR1(address 0F9H) to “1”.
For PSR1 register, refer to Figure 16-2 .
Example: 5kHz output at 4MHz.
LDM BUZR,#0011_0001B
LDM PSR1,#XXXX_X1XXB
X means don’t care
The bit 0 to 5 of BUZR determines output frequency for buzzer
driving.
Equation of frequency calculation is shown below.
fBUZ = 2------×----D-----i--v----i--d----e----R----af---X-t--iI--No-----×-----(---B----U-----R------+-----1----)
fBUZ: Buzzer frequency
fXIN: Oscillator frequency
Divide Ratio: Prescaler divide ratio by BUCK[1:0]
BUR: Lower 6-bit value of BUZR. Buzzer period value.
The frequency of output signal is controlled by the buzzer control
register BUZR. The bit 0 to bit 5 of BUZR determine output fre-
quency for buzzer driving.
XIN PIN
÷8
00
÷ 16
01
÷ 32
10
÷ 64 11
MUX
2
[0E0H]
R12 port data
6-BIT BINARY
COUNTER
F/F
Comparator
Compare data
6
BUR
Internal bus line
MUX
0
R12/BUZO PIN
1
BUZO
PSR1 Port selection register 1
[0F9H]
Figure 16-1 Block Diagram of Buzzer Driver
BUZR
WW
ADDRESS: 0E0H
RESET VALUE: 0FFH
WWWW WW
BUCK1 BUCK0
BUR[5:0]
Buzzer Period Data
Source clock select
00: fXIN ÷ 8
01: fXIN ÷ 16
10: fXIN ÷ 32
11: fXIN ÷ 64
ADDRESS: 0F9H
RESET VALUE: ---- 0000B
PSR1 -
-
-
-
- BUZO -
-
R12 / BUZO Selection
0: R12 port (Turn off buzzer)
1: BUZO port (Turn on buzzer)
Figure 16-2 Buzzer Register & PSR1
October 31, 2011 Ver 1.03
77
Share Link: 