Datasheet

Application Note
www.tektronix.com/oscilloscopes38
Working with DSI-1 and CSI-2
The SR-DPHY application enables decoding of DSI-1 and
CSI-2 buses. To set up a bus, simply go the Bus Setup Menu,
select Serial, and then select either MIPI DSI-1 or MIPI CSI-2.
In the screenshot below, we’ve selected DSI-1.
To configure the bus we need to specify the types of channels
(analog vs. digital) and probes being used to probe the bus.
When using analog channels, a differential probe is used to
probe the clock and two single-ended probes are used to
probe the data lane. The P6780 differential probe enables
the MSO70000C Series to probe one or more lanes using
the digital channels. One channel is used to probe the clock,
one channel probes the differential signal D+/D-, one channel
probes the single-ended signal D+/GND, and one channel
probes the single-ended signal D-/GND. Therefore, three
analog channels or four digital channels are required to probe
a single-lane DSI-1 or CSI-2 implementation.
Once configured and displayed, the busform shows all the
decoded components of both short packets and long packets
as well as other communications types such as Bus Turn
Around (BTA) and Escape Mode Commands.
By default, the virtual channel and the word count fields are
displayed in decimal. The Data Type field indicates the type of
packet. ECC and Checksum are both displayed in hex. Finally,
for defined data types, the payload field decodes the data
being transmitted into relevant display-type information. In the
example shown above, the first pixel value transmitted in the
payload has a Red value of 255, a Green value of 216, and a
Blue value of 0.
In addition to decoding DSI-1 / CSI-2 acquisitions, you can
also search through long acquisitions to find all occurrences of
the following types of packet content:
Short packets (specify VC, DT, Direction, and Packet
Data values)
Long packets (specify VC, DT, Direction, WC, and Data
Payload including Pixel values)
Stop
Start of Transmission (SoT)
End of Transmission (EoT)
Bus Turnaround (DSI-1 only)
Escape Mode
ECC Warning
ECC Error
Checksum Error
With the SR-DPHY application and the appropriate Tektronix
oscilloscope (see Appendix A), you can easily decode and
view DSI-1 and CSI-2 serial bus packets, analyze them, and
correlate them to other activity in your device.
Figure 52. MSO70000C digital-channel decoded display of a Packed Pixel Stream, 24-
bit RGB 8-8-8 Format long packet.
Figure 53. MSO70000C analog-channel decoded display of a Packed Pixel Stream,
showing a checksum error.
Figure 51. MIPI DSI-1 Bus Setup.