C/spi interface – Rainbow Electronics MAX1386 User Manual

Page 44

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MAX1385/MAX1386

Dual RF LDMOS Bias Controllers
with I

2

C/SPI Interface

44

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3) Send 16 bits of data (D15–D0) starting with the most

significant bit and ending with the least significant
bit. Data is clocked in on the rising edges of SCL.

4) Pull

CSB high.

Read Format

Use the following sequence to read 16 bits of data from
a MAX1385/MAX1386 register (see Figure 19):

1) Pull

CSB low to select the device.

2) Send the appropriate read command byte (see the

Command Byte

section). The command byte is

clocked in on the rising edges of SCL.

3) Receive 16 bits of data. Data is clocked out on the

falling edges of SCL.

4) Pull

CSB high.

Command Byte

The MAX1385/MAX1386 use read and write command
bytes. The command byte consists of 8 bits and contains
the address of the register (C7–C0, see Figures 18 and
19). The command byte also communicates to the
device whether a read or write operation occurs. See the

Register Description

section for details on how to access

specific registers through the command byte.

Data Bytes

Data bytes are clocked in/out of the device with the
most significant bit first and the least significant bit last
(D15–D0, see Figures 18 and 19). See the

Register

Description

section for a description of data bytes for

each register.

SCL

SDA

S

1

2

8

9

NOT ACKNOWLEDGE

ACKNOWLEDGE

Figure 20. Acknowledge Bits

SCL

C6

C5

C4

C3

C2

C1

C0

D15

D14 D13 D12

D11 D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

CR/W

DIN

CSB

A RISING EDGE OF CSB
DURING THIS PERIOD
COMPLETES A VALID
WRITE COMMAND.

Figure 18. SPI Write Format

SCL

C6

C5

C4

C3

C2

C1

C0

D15

D14 D13 D12 D11 D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

CR/W

DIN

CSB

DOUT

Figure 19. SPI Read Format

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