houkime | I would expect sth of the order of 100 Mhz but i really don't know. | 00:11 |
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houkime | CSI seems quite challenging. I assume that it is D-PHY thing, with one DP for forward stream , one DP for reverse stream, and one more DP for clock. | 00:22 |
houkime | And the speed on this this is around 1 Gbit/s | 00:22 |
houkime | And two streams and clock need to be completely independent from each other. | 00:23 |
houkime | and _yet_ be synchronized, all 3 of them. | 00:23 |
houkime | So you probably can't really just lay them out as a 6-wire band. | 00:24 |
houkime | because they will crosstalk | 00:24 |
houkime | umm, maximum skew between clock and each of the DPs is 1.5mm | 00:34 |
houkime | kinda tense | 00:35 |
houkime | It is a bit strange that schematics refers to CSI as DSI, CSI while feasibility study says that n900 uses SPI for display. So it is actually a CSI for a front camera. | 00:37 |
houkime | *as DSI/CSI | 00:37 |
houkime | might be a good call to make some simple tests with bb-xm <-> ACX565AKM first | 00:47 |
houkime | moreover, on the v2 board these 3 DPs should actually go the other direction from where they need to go in the final design | 01:00 |
houkime | which actually means somehow you need to turn all 3 of them 180 degrees without violating maximum skew of 1.5 mm | 01:01 |
houkime | between clock and each DP | 01:01 |
houkime | I prepared an illustrated issue on display CSI bus routing. https://notabug.org/Houkime/Neo900/issues/31 | 02:10 |
houkime | Joerg-Neo900, is this (a bit strange) pinout of differential pairs on bb-xm connector intentional? | 02:11 |
houkime | (illustrated in the issue) | 02:11 |
houkime | What were the considerations for such an arrangement? | 02:12 |
houkime | If it is intentional and planned, what are the skews on the bb-xm itself both intra-pair and inter-pair? | 02:20 |
houkime | Funny enough v2 prototype docs never even mention front camera | 02:31 |
houkime | But it exists. And CSI stuff is clearly for the front camera. | 02:32 |
houkime | And it might be a nice idea to fit a hardware killswitch there. | 02:34 |
houkime | later | 02:34 |
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