© 2018 Integrated Device Technology, Inc.

17

September 11, 2018

F1240 Datasheet

Programming

Serial Mode

word is the address or channel word, which uses only 1 of 8 bits to select the channel that will be programmed. The second 8 bit word is the

Gain (or attenuation) word, which uses 6 bits to control the DSA state and one bit to enable or disable the channel.

When serial programming is used, all of the other parallel control input pins (3, 6-10, 25, 31, 32) can be left floating.

Table 8.

8-Bit SPI Address (Channel) Word Sequence

Data Bit

Symbol

A7

Not Used

A6

Not Used

A5

Not Used

A4

Not Used

A3

Not Used

A2

Not Used

A1

Not Used

A0

Channel Selection

Table 9.

Truth Table for Address (Channel) Control Word

A7

(MSB)

A6

A5

A4

A3

A2

A1

A0

(LSB)

Program Channel

0

0

0

0

0

0

0

0

A

0

0

0

0

0

0

0

1

B

Table 10. 8-Bit SPI Gain (Attenuation) Word Sequence

Data Bit

Symbol

D7

Enable Bit

D6

Attenuation 16 dB Control Bit

D5

Attenuation 8 dB Control Bit

D4

Attenuation 4 dB Control Bit

D3

Attenuation 2 dB Control Bit

D2

Attenuation 1 dB Control Bit

D1

Attenuation 0.5 dB Control Bit

D0

Not Used