Technical data

Verifying I

S Serial Bus Communication 11

Agilent InfiniiVision 7000B Series Oscilloscopes Evaluation Guide 59

You should now see I

S decoding based on 8-bit words of “left” channel

and “right” channel data. Note that this might represent stereo

information in a digital audio/sound system. Let’s now set up the

oscilloscope to trigger on a specific transmitted audio data.

12 Press [Trigger]; then, select the I

S trigger mode.

13 Press Trigger Setup to view the default I

S trigger condition.

Note that the default trigger condition is to trigger when the left-channel

data equals “0” (signed decimal value), and we can see that this

condition occurs when the analog waveform on channel 2 (green trace)

crosses through the 50% level of a sine wave output in either the positive

or negative direction. Let’s now set up the oscilloscope to trigger on a

specific direction of the output analog signal (increasing or decreasing

data value).

14 Press Trigger =; then,

select (Increasing Value)

as the trigger condition.

The oscilloscope should

now be triggering on +20,

which is the first

left-channel data value

captured after crossing

through -10 and +10