GMS81C5108 Datasheet, PDF(63/102 Page) Hynix Semiconductor – HYNIX SEMICONDUCTOR INC. 8-BIT SINGLE-CHIP MICROCONTROLLERS

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GMS81C5108 Datasheet, PDF (63/102 Pages) Hynix Semiconductor – HYNIX SEMICONDUCTOR INC. 8-BIT SINGLE-CHIP MICROCONTROLLERS

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GMS81C5108

15. Buzzer Output Function

The buzzer driver consists of 6-bit binary counter, the

buzzer data register BDR and the clock selector. It gener-

ates square-wave which is very wide range frequency (500

Hz~125 KHz at fMAIN = 4MHz) by user programmable

counter.

Pin R04 is assigned for output port of Buzzer driver by set-

ting the bit BUZ of Port Mode Register (PMR) to â1â.

The 6-bit buzzer counter is cleared and start the counting

by writing signal to the register BDR. It is increased from

00H until it matches with BDR[5:0].

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 BDR determines output frequency for

buzzer driving. BCD is undefined after reset, so it must be

initialized to between 0H and 3FH by software. Note that

BDR is a write-only register. Frequency calculation is fol-

lowing as shown below.

fBUZ(Hz) = 2-----Ã-----P---r--Oe---s-s-c-c--a-i-l-l-el--a-r--t-Ro----ra---Ft--i-ro--e---Ãq---u--(-e-B--n--C-c--y--D-----+-----1----)

The bits BCK1, BCK0 of BDR select the source clock

from prescaler output

fBUZ: BUZ pin frequency

Prescaler ratio: Prescaler divide ratio by BDR[7:6]

BCD value: 6-bit compare data, BCD[5:0].

BDR (Buzzer Data Register)

W

Bit : 7

BCK1

W

6

BCK0

W

5

BCD5

W

4

BCD4

W

3

BCD3

W

2

BCD2

W

1

BCD1

W

0

BCD0

BCK[1:0] (Buzzer Clock Source)

00: fMAINÃ·23

01: fMAINÃ·24

10: fMAINÃ·25

11: fMAINÃ·26

or fSUBÃ·23

or fSUBÃ·24

or fSUBÃ·25

or fSUBÃ·26

BCD[5:0] (Buzzer Control Data)

Buzzer Period Data

ADDRESS : 0FDH

RESET VALUE : 00H

Bit manipulation is not available.

PMR (Port Mode Register)

- PWMO - BUZ EC0 INT2 INT1 INT0

ADDRESS :0D9H

RESET VALUE : -0-00000B

SCMR[1:0]

2

XIN

0X

SXIN

1X

Ã·8

Ã· 16

Ã· 32

Ã· 64

BUZ (Buzzer Output)

0: R04 Port (turn off buzzer)

1: BUZ port (turn on buzzer)

MUX

COUNTER (6-bit)

BCK[1:0]

F/F

COMPARATOR

BCD (6-bit)

BUZ

[PMR.4]

R04/BUZ PIN

Figure 15-1 Buzzer Driver

Example: 2.5kHz output at 4MHz.

LDM R0DR,#XXX1_XXXXB

LDM BDR,#1001_1000B

LDM PMR,#XXX1_XXXXB ;Buzzer ON

X means donât care

60

JUNE 2001 Ver 1.0

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