NEC PD17062 - page 99

PD17062

10.5.3 Presettable Shift Register

Fig. 10.6 shows the functions of the presettable shift register.

The presettable shift register writes the serial interface serial out data and reads the serial interface serial

in data.

Fig. 10-6 Relationship between Presettable Shift Register and Data Buffer

Serial interface serial data is output while being shifted sequentially the data from the MSB (bit b7) of the

presettable shift register.

During serial data input, data is shifted sequentially from the LSB (bit b0).

DBF3

0CH

DBF2

0DH

DBF1

0EH

DBF0

0FH

b15 b14 b13 b12 b11 b10 b9b8b7b6b5b4b3b2b1b0

b7b6b5b4b3b2b1b0

D7 D6 D5 D4 D3 D2 D1 D0

SIO0SFR 03H

Serial out data write and serial in data read

12345678

MSB LSB

Data output timing

×D7 ×D6 ×D5 ×D4 ×D3 ×D2 ×D1 ×D0

12345678

MSB LSB

Data input timing

×D7 ×D6 ×D5 ×D4 ×D3 ×D2 ×D1 ×D0

Symbol Peripheral

address Peripheral hardware

Name

Peripheral register

Name Data buffer

Symbol

Address

Bit

Data Don't care Don't care Transfer data

GET

PUT

Valid data

Presettable

shift register Serial interface

Serial out data

Clock

Serial in data

Clock