USB 2.0 max fanout 127...!
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USB 2.0 max fanout 127...!
can I use 3.5 tiers of 4 port powerd usb hubs to power 127 flash chips or is there a SS USB limit on size? anything else worth trying. I assume the speed and bandwidth will be a bit weak at the host, but any thing to look out for (i know <=5 tiers deep) i dont think 7 port hubs would change anything (other than configuration)
any ideas/suggestions?
Me
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No because the hubs themselves are classed as USB devices! So 37 hubs would only leave space for 90 drives.
By using 3.25 tiers you could get 94 Drives with 2 free ports remaining
Of course that's all using 4 port hubs, 7 port hubs would reduce the number of devices used to simply create ports, freeing the number of devices for actual drives.
I hope that makes sense.
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perfect sense, I can't believe I didn't even consider the hubs, completely eluted me, thanks the 7 v. 4 port USB hub does have merit, weighing heavily on the seven side.
but wait. Ive actually interfaced a USB 2.0 to a circuit (microcontroller type thing written in assembler and then the hex is burned onto a eeprom or flash IC) well I cant remember the code for the chip but are you pretty sure a 7 port hub doesn't require the resources of two USB devices, because there are two of the identical (or nearly) IC's each can "tetraforcate":) 1 to 4 by supplying data to the chip to multiplex the signal. so the second chip can tap its input into one (1) output of the first chip (reducing it to 3 outputs, and supplying the second chip which has all 4 outputs. This accounts for the 4/1 :: 7/1 arrangement scheme, but i the second chip would require a USB resource, since the arrangements constraints seem to not allow for one chip control.
I HOPE THAT MAKES SENSE!
my reason for bringing this up is it wouldn't be that difficult (esp if you are right rather then me) to wire 4 ICs to draw their input from the four outs of the first chip, allowing for one device to control 4x4=16, and this would make the chips seem preferable to fan out than the routers, prewired with only 1 or 2 chips
hope that makes sense too.
Thanks for the first answer anyway!
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Well you seem to know more about hubs than I do, It makes sense that 7 ports are derrived from a +4 daisy chained into a +4 (taking 1) leaving 7 ports (if you plug a 7port hub in do you get 2 new USB ports showing in device manager would give you the answer i suppose). I don't know the answer to that but I should imagine you are right.
Of course you may benefit from the change in topology if you used the 2 ports at the source that are on the same controller instead of just one. Then It could be done in 2 banks of 3 tiers, instead of having some devices on a 4th tier.
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Sorry I wasn't accusing that you wouldn't understand, I had just confused myself a bit trying to articulate the situation.
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Sorry I wasn't accusing that you wouldn't understand, I had just confused myself a bit trying to articulate the situation.
of course I understood, Izz jus kiddn - I figured i was typing as thoughts were forming and then extra keys get pressed and the whole thing doesnt make sense....and thats for simple things....when I'm actually actively describing something before/as I'm possibly grasping it myself....it just seemd to fit naturally.
good times.. i have some ideas to mess with....nice when products approch the end of their life (becoming nearly obsolete in many ways) I get to play with toys from my shop, so I will be litterally laying in a pile of USB hubs at some point
BUT THNKS FOR YOUR ADVICE!
Mike
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Yeah, and many multi-sockets to plug all those hubs in!
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