USB OTG Boot

[devilsclaw]

The VBUS connect to a power switch LPW5210B5F with pine 4 en pin tie to high and Rset set as 10K. Here is the LPW5210 data sheet link: http://www.kcttek.com/uploads/soft/LPW5210.pdf. Please lets us know on your concern so that we can explore together.

Thanks! I was just curious about the use of USB OTG. If somebody plugs a USB A-A cable to the lower connector, then the PC is going to be providing +5V on VBUS, which is potentially undesirable. But the LPW5210B5F power switch has reverse current protection. Though I'm not quite sure if it is a good idea to have the EN pin pulled up by default (enabling the VBUS power on reset) for the lower USB connector. As for detecting the "device" vs. "host" mode, please have a look at USB0-VBUSDET on the A13 tablet reference schematic. This might be an alternative to the unavailable ID pin.

But admittedly this all is about a rather niche feature, because the majority of users will probably not care about booting over USB.

BTW, can anyone with a Pine64 board and USB A-A cable check if the FEL mode is actually available and paste the "sunxi-fel ver" output?

Please PM me with your shipping address, I just want make sure that you are in the developer distribution list. If we missed your name, I will include. Thanks.

Thanks on the tips and I will look into it.

Thanks for the update on the info for the schematic. I don't know why people are trying to inflame this at ever corner. also thamls ssvb for the info

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Just to let you know my Idea of how I would use the USB boot, if we can get it running.

this depends on how much SRAM is available on the CPU so it might need to be more complex.

if there is enough SRAM then use the first stage boot loader to get the DRAM and Ethernet initialized, second stage gets pulled through Ethernet, second stage init all hardware that is needed besides DRAM, third stage is the full u-boot, and finally load everything from Ethernet into DRAM and boot. this being more of an embedded linux style just for kernel development. or instead of a ramfs image it could also be a NFS boot at that point.

This would allow a lot faster development of just about anything.