UNSOLVED GX-MIPI-IMX662 on RK3588 with Kernel 6.1 - MIPI CSI Errors
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@xlwvu7mx
Hello, the MIPI data rate of the GX series products is indeed higher than that of the VEYE series: GX: 1188 Mbps, VEYE: 594 Mbps. Based on the issues you are experiencing, I mainly suspect the MIPI signal quality. Please pay special attention to the following:-
What is the length of your FFC cable?
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About your adaptor board:
- Have the differential pairs been length-matched? (This is required.)
- Has impedance matching been implemented? (Strongly recommended.)
- Are there any ESD protection devices with large junction capacitance on the signal lines?
- Could you take a photo of your actual connection and send it to me for review?
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@veye_xumm
Thank you for your reply. The lenghts were:- 20 cm from camera to adapter using stock white 22-pin FFC cable
- 10 cm from the adapter to the board itself using 31-pin cable.
I've done some experiments today with different cable length combinations and various results.
CSI0:
- 22-pin 20 cm + 31 pin 15 cm. 0 fps, ecc2, fs/fe, f_seq errors.
- 22-pin 10 cm + 31 pin 10 cm. 14-38 fps, very unstable with dropped buffers, ecc2, fs/fe, f_seq errors.
- 22-pin 20 cm + 31 pin 10 cm. 0 fps, ecc2, fs/fe, f_seq errors.
- 22-pin 10 cm + 31 pin 15 cm. 0 fps, ecc2, fs/fe, f_seq errors.
CSI1:
- 22-pin 20 cm + 31 pin 15 cm. 60 fps, no errors.
- 22-pin 10 cm + 31 pin 10 cm. 60 fps, crc, err_data errors.
- 22-pin 20 cm + 31 pin 10 cm. 60 fps, crc, err_data errors.
- 22-pin 10 cm + 31 pin 15 cm. 60 fps, no errors.
So, the new information is that CSI0 managed to receive at least some data and there are combinations of cable length (that are suprisingly longer) that make errors disappear completely on CSI1. As far as I can judge, this indicates hardware problems rather than issues with, for example, dt overlays.
Regarding your question about adapter board. Differential pairs are length matched. I will request information about impedance matching from the developer of that board. The adapter only contains voltage stab and I2C level adapter - MIPI lanes are connected directly.
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@xlwvu7mx
Based on our experience, under normal circumstances an FFC cable length within 50 cm does not cause any issues. We have tested a setup with a 20 cm FFC cable + an adapter board + a 50 cm FFC cable, and it worked normally. Could you please provide some photos of the actual setup so we can take a look? -
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@xlwvu7mx
I don't think it's a cable length issue or a DTS problem. Have you tried testing with a different adapter board or a different mainboard? I tested it with an Orange Pi CM5, using a 50cm FFC cable plus a 20cm FPC cable, and the image was very stable.
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@veye_xumm
With your setup in mind it seems that the issue can be in my adapter, main board or 31 pin FFC cable connection. I will continue investigation of the issue possibly with another main board and adapter. Thank you for your advice so far.Also, I've noticed that GX manuals for Firefly and Orange Pi mention FFC cables that connect camera to the board directly and GX-MIPI-IMX662 Data Sheet page tells the camera now accepts I2C 1.8V level. So I think I will try direct connection as well.
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@xlwvu7mx said in GX-MIPI-IMX662 on RK3588 with Kernel 6.1 - MIPI CSI Errors:
Also, I've noticed that GX manuals for Firefly and Orange Pi mention FFC cables that connect camera to the board directly and GX-MIPI-IMX662 Data Sheet page tells the camera now accepts I2C 1.8V level. So I think I will try direct connection as well.
OK
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@veye_xumm
I have conducted some more experiments with another similar board, different kernel versions, with some electrical adapter modifications and a much shorter 31-pin FFC cable. The issue is exactly the same however.I think the problem is probably in my adapter board, less likely in a board layout itself. I am considering making and FPC for direct connection from sensor to camera like ones that you now offer for Firefly boards.
Do you have any recomendations on a FPC cable design? And could you please confirm the 22-pin connector pinout featured on the GX-MIPI-IMX662 Data Sheet page (as I have seen both reset_gpio and pwdn_gpio pins in the driver source code where the page mentions only PWR_ENABLE).
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@xlwvu7mx said in GX-MIPI-IMX662 on RK3588 with Kernel 6.1 - MIPI CSI Errors:
Do you have any recomendations on a FPC cable design? And could you please confirm the 22-pin connector pinout featured on the GX-MIPI-IMX662 Data Sheet page (as I have seen both reset_gpio and pwdn_gpio pins in the driver source code where the page mentions only PWR_ENABLE).
Sorry, I am currently on the Spring Festival holiday. As for the camera, in fact only one pin is functional:PWR_ENABLE
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@veye_xumm
Thanks for the answer, have a happy holiday!
