cancel
Showing results for 
Search instead for 
Did you mean: 

USB Superspeed Peripherals

HuEl_264296
New Contributor II

When calculating all of the timings in the MIPI receiver configurator, the CSI clock seems to be calculated as:

V-Total x H-Total x FPS x bitsperpixel

E.G. with 640 x 480 x 60fps x 8bits, with 1 lane, the CSI clock is calculated to be 73.73MHz exactly.

This seems surprising, as I would have thought there would be 8b/10b encoding, and perhaps some SoF / EoF / CRC bytes included too.

Why doesn't the CSI clock need to take these extra bytes into account?

0 Likes
1 Solution
KandlaguntaR_36
Moderator
Moderator

Edited:

As per Analysis of CX3 Video Timing Parameters – KBA226779

The minimum CSI clock required=  (H-Active (in Pixels) × Pixel Depth) ÷ H-Total (in µs) ÷2 ÷ Data Lanes

i.e.                                                  = (640 X 😎 / 31.67 /2 /1 = 80.833 Mhz

Here 31.67 us is taken from Please help me understand timing of these MIPI waveforms .

In general, this value will be less than this number. Because 31.67 us includes the headers as well.

Encoding is optional in MIPI CSI-2. Error correction code (24-bit) will be part of data packetheader and 16 bit checksum in packetfooter.

You can see this in this figure.

pastedImage_4.png

View solution in original post

0 Likes
1 Reply
KandlaguntaR_36
Moderator
Moderator

Edited:

As per Analysis of CX3 Video Timing Parameters – KBA226779

The minimum CSI clock required=  (H-Active (in Pixels) × Pixel Depth) ÷ H-Total (in µs) ÷2 ÷ Data Lanes

i.e.                                                  = (640 X 😎 / 31.67 /2 /1 = 80.833 Mhz

Here 31.67 us is taken from Please help me understand timing of these MIPI waveforms .

In general, this value will be less than this number. Because 31.67 us includes the headers as well.

Encoding is optional in MIPI CSI-2. Error correction code (24-bit) will be part of data packetheader and 16 bit checksum in packetfooter.

You can see this in this figure.

pastedImage_4.png

View solution in original post

0 Likes