[AP1021]

015000428-E-00

2015/01

- 14 -

1. Data Writing and Reading Modes on Every Address

Internal registers are written by using 4-wire serial interface pins (CSN, SCK, SDI and SDO). The data on

this interface consists of Register address (MSB first, 7bits), Read/Write and Control data or Output data

(MSB first, 8bits). Address and data is clocked in on the rising edge of SCK and data is clocked out on the

falling edge. Data writings become available on the rising edge of 16th falling edge of SCK. When reading

the data, the SDO pin outputs data in D7-D0 at the falling edge of 8th SCK. Clock speed of SCK is 2MHz

(max). In write mode, after recognizing D0 by “↑” of SCK, CSN have to be set “L” → “H”.

CSN

SCK

1

2

3

4

5

6

7

8

9

10 11

12 13 14 15

16

A6-A0:

Register Address (7bit)

R/W:

READ/WRITE select bit (1bit) 

“L”: WRITE

D7-D0:

Control data Input at Write Command (8bit)

“L”

“L”

SDI

A6

A5

A2

A3

A1 A0

A4

D7 D6 D5 D4 D3 D2 D1 D0

“H” or “L”

“H” or “L”

W

Figure 4. Serial Control Interface Timing (write mode)

CSN

SCK

1

2

3

4

5

6

7

8

9

10

11 12 13 14 15

“L”

“L”

SDI

A6

A5

A2

A3

A1 A0

A4

“H” or “L”

“H” or “L”

R

A6-A0:

Register Address (7bit)

R/W:

READ/WRITE select bit (1bit) 

“H”: READ

D7-D0:

Output data at Read Command (8bit)

SDO

D7 D6 D5 D4 D3 D2 D1 D0

“Hi-Z”

o

“L”

“Hi-Z”

o

“L”

16

“H” or “L”

Figure 5. Serial Control Interface Timing (read mode)