VXI SM8000 user manual Write Example, Read Example

VXI Technology, Inc.

COMMAND REGISTER

The following register addressing is based on the Phillips I2C specification. For more detailed information, please refer to Phillips document titled The I2C Bus and How To Use It.

Bits

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

D

R

R

R

D

W

W

W

C

C

C

C

C

C

C

C

D

Don’t Care

R

Number of data bytes to be read back from the optical module plus 1.

Range: 8 to 0 decimal.

Number of data bytes to be written to the optical module. This number should

W

include the Address and Command Bytes, along with the number of data

bytes that are to be written to the module.

Range: 8 to 0 decimal.

C

Command Byte. See Attenuator Command Set.

Write Example

Command optical module to Move-To-Absolute-Step:

W = 1 Address Byte + 1 Command Byte + 2 Data Bytes to Send = 4

R = 0 (no data is expected back)

C = 30h

Command Register = 0430h

Read Example

Query optical module’s Current Step:

W = 1 Address Byte + 1 Command Byte + 0 Data Bytes to Send = 2

R = 2 Data Bytes to Read Back + 1 = 3

C = 31h

Command Register = 3231h

60 SM8000 Series Programming