CLC5506PCASM datasheet(9/12 Pages) NSC

9 / 12 page

APPLICATION NOTE (Continued)

MICROWIRE™ Interface

Data In along with the Clock, LE, and Data Out, is used for

the following purposes:

Setting the 6-bit gain control code

Putting the device into a Power Up/Down mode to mini-

mize power consumption

Daisy chain several CLC5506 or other MICROWIRE In-

terface devices through the Data Out pin

The MICROWIRE interface timing diagram along with the bit

assignment of all 8 bits is shown in

Figure 2. The interface is

active only when LE (pin 5) is low; otherwise, the interface is

inactive (Clock and Data In are ignored) and the CLC5506

gain is the current content of the 6 bits already read into the

device.

With LE low, each successive positive transition of Clock will

read the value of the Data In into a series of 8 single bit shift

registers. In order to load all 8 registers, 8 Clock transitions

are required after which, when LE is allowed to go High, the

new values in the shift registers are latched to determine the

device gain setting (or Power Down state). New data can be

shifted into the device with the present gain setting not af-

fected as long as LE is held low.

Data from the last register in the chain is clocked out on Data

Out pin on the negative transitions of Clock as shown in

Fig-

ure 3. This enables several MICROWIRE Interface devices

to be daisy chained and controlled from a single bus master.

The maximum clock frequency (Clock pin) is 1MHz.

DS101050-18

Note:

1. Data is clocked in on the rising edge of Clock.

2. Power Down bit is the first data to enter the CLC5506.

FIGURE 2. MICROWIRE Interface Timing Diagram

DS101050-19

FIGURE 3. MICROWIRE Interface Serial Data Out Timing

CLC5506PCASM Datasheet(PDF) 9 Page - National Semiconductor (TI)