W742C814 データシートの表示（PDF） - Winbond

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W742C814

4-BIT MICROCONTROLLER

Winbond 

W742C814

release enable flag 7 is set to 1 (HEF.7 = 1), the hold state is terminated. The specified frequency of

Timer 1 can be delivered to the MFP output pin by programming bit 2 of MR1. Bit 3 of MR1 can be

used to make Timer 1 stop or start counting.

In a case where Timer 1 clock input is FT:

Desired Timer 1 interval = (preset value +1) / FT

Desired frequency for MFP output pin = FT ÷ (preset value + 1) ÷ 2 (Hz)

Preset value: Decimal number of Timer 1 preset value

FOSC: Clock oscillation frequency

Fslow

Fosc/64

Fosc

MR1.0

MOV TM1H,R

MOV TM1L,R

MR1.1

MR1.3

4

4

Auto-reload buffer

Enable

8 bits

FT

8-Bit Binary

Down Counter

(Timer 1)

Disable

8 bits

Reset

MOV WR,TM1

S

Q

R

Underflow signal

EVF.7

1. Reset

2. INT7 accept

3. CLR EVF, #80H

4. Set MR1.3 to 1

2

circuit

Reset

MFP

signal

MFP

output pin

BUZCR.0

Set

MR1.3 to 1

Figure 6-7 Organization of Timer 1

For example, when FT equals 32768 Hz, depending on the preset value of TM1, the MFP pin will

output a single tone signal in the tone frequency range from 64 Hz to 16384 Hz. The relation between

the tone frequency and the preset value of TM1 is shown in the table below.

MOV WR, TM1 can read back the content of TM1, It will save the TM1 MSB to WR and the TM1 LSB

to ACC.

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Publication Release Date: February 12, 2003

Revision A2

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