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AS8530

Preliminary Data Sheet - A p p l i c a t i o n I n f o r m a t i o n

8.7.1.2 Write Command

For Write command RD/WR = 0

After the command code, length of the transfer is send in next two bits, the address of register to be written has to be provided from the MSB to

the LSB. Then one, two, four, or eight data bytes can be transferred from the MSB to the LSB. For each data byte following the first one, used

address is the incremented value of the previously written address. Each bit of the frame has to be driven by the 2-Wire SP master on the SP

clock (EN pin) positive edge and the 2-Wire SP slave (device) samples this bit on the next SP clock (EN pin) negative edge. In the following

figures two examples of write command (without and with address self-increment).

Figure 14. Protocol for Serial Data Write with Length = 1

Figure 15. Protocol for Serial Data Write with Length = 4

8.7.1.3 Read Command

For Read command RD/WR=1.

After the command code, length of the transfer is send in next two bits, the address of register to be read has to be provided from the MSB to the

LSB. Then one, two, four or eight data bytes can be transferred from the SPI slave to the master, always from the MSB to the LSB.

Each bit of the command and address sections of the frame have to be driven by the 2-Wire SP master on the SP clock (EN pin) positive edge

and the 2-Wire SP slave (device) samples this bit on the next SP clock (EN pin) negative edge. Each bit of the data phase of the frame has to be

driven by the 2-Wire SP slave (device) on the SP clock (EN pin) positive edge and the 2-Wire SP master samples this bit on the next SP clock

(EN pin) negative edge. The following figures illustrate two examples of read command (without and with address self-increment.)

EN

TX

0

LEN1

LEN0

A4

A0

A1

A2

A3

D0

D1

D2

D3

D4

D5

D7

D6

Transfer edge

Sampling edge

Data D7 – D0 is moved to

Address A4..A0 here

LEN1 = 0

LEN0 = 0

Command & Address Phase

Data Phase

Length of Transaction = 1

EN

TX

1

LE

N1

LE

N0

A

4

A

0

A

1

A

2

A

3

D

0

D

1

D

2

D

3

D

4

D

5

D

7

D

6

D

0

D

1

D

2

D

3

D

4

D

5

D

6

D

0

D

1

D

2

D

3

D

4

D

5

D

6

D

7

D

7

D

1

D

2

D

3

D

4

D

5

D

6

D

7

D

0

Data D7-D0 is moved

to Address A4-A0

here

10

Command & Address

Phase

Data1 Phase

Data2 Phase

Data3 Phase

Data4 Phase

LEN1 = 1

LEN0 = 0

Length = 4

Data D7-D0 is moved

to Address A4-A0 + 1

here

Data D7-D0 is moved to

Address A4-A0 + 2 here

Data D7-D0 is moved

to Address A4-A0 + 3

here