Do I need to account for 8b10b encoding in MIPI timing?

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HuEl_264296
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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?

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KandlaguntaR_36
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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

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KandlaguntaR_36
Moderator
Moderator
Moderator
25 solutions authored 10 solutions authored 5 solutions authored

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

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