SM565 View Datasheet(PDF) - Sharp Electronics

Part Name

Description

Manufacturer

SM565

4-Bit Single-Chip Microcomputer

Sharp Electronics 

4-Bit Single-Chip Microcomputer

SM565

Timer/Counter and the SND Signal

The timer/counter consists of an 8-bit count register

(TC) and an 8-bit modulo register (TM).

The count register is an 8-bit incremental binary

counter. It is incremented by one at the falling edge of

its count pulse (CP) input. If the count register over-

flows, the timer interrupt request flag IFT is set, and the

contents of the modulo register (TM) are loaded into

the count register (see Figure 7).

The count pulse Cp can be selected from divider sig-

nals fIn and f0, and the system clock, by using the mode

register RD. If the count register (TC) overflows, the

SND flag reverses its status at the falling edge of the

TC. A sound signal can be obtained at the TC output by

putting P2 in output mode and sending a ‘1’ to pin P23

(see Figure 8).

Serial Interface and IFS

The serial interface consists of an 8-bit shift register

(SB) and a 3-bit counter, which is used to input and out-

put the serial data. The serial clock can be selected

with either an internal clock (system clock) or an exter-

nal clock.

In serial shift operations, the highest bit data of the

shift register (SB) is output from the SO pin, and the data

input from the SI pin at the rising edge of a serial clock is

loaded into the lowest bit of the shift register. When the

internal clock is used, immediately after the SIO instruc-

tion is executed, the serial operation begins and stops

with eight clocks which are output from the SCK pin.

Upon completion of an 8-bit shift operation, the

serial I/O ending flag IFS is set each time a 3-bit

counter overflows, and an interrupt request occurs.

LDTC

B, A

STTM

TM (8)

OVERFLOW

STTC

COUNT PULSE

CP

TC (8)

BINARY COUNTER

INT T + TSTT

IFT

SQ

R

565-9

Figure 7. Timer/Counter

TC(8)

SND FLAG

TQ

R23

A

RF3

Figure 8. SND Signal

P23

565-10

P32/SO

P30/SI

P31/SCK

8 - BIT SB REGISTER

SERIAL CLOCK OUTPUT

DATA SHIFT REQUEST

SERIAL

CLOCK

SELECTOR

3 BIT CNT

TRANSFER END SIGNAL

SQ

REGISTER

INTERNAL CLOCK

EXTERNAL CLOCK

φ1

QR

S

TSTS

R

SIO

IFS FLAG

Figure 9. Serial Interface

565-11

Microcomputer Data Sheet

11

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