using microcontroller to manage USB host enumeration

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pendragon_01
 
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Re: using microcontroller to manage USB host enumeration

Post by pendragon_01 »

this thread is quickly becoming a MCU 101 master class :)

my enumeration question was answered on the pjrc forum. i was subsequently asking about voltage requirements/IO for the teensy 2.0, which i gather is 5v with 25 pins. and yes, i'd be happy to x-post any answers.

quick follow-up question: any idea if the teensy can be bypassed once usb enumeration is complete? i would think so since any client peripheral, once completely enumerated by the host device, would then cease the enumeration process, load the peripheral driver and then be ready for use.

thoughts? thanks!

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paulstoffregen
 
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Re: using microcontroller to manage USB host enumeration

Post by paulstoffregen »

Did you post this same question on any other forums?

pendragon_01
 
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Re: using microcontroller to manage USB host enumeration

Post by pendragon_01 »

:) not sure if that is completely on topic but the answer is no and if i did i have already said i would cross post the answer.

any thoughts on the question?

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paulstoffregen
 
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Re: using microcontroller to manage USB host enumeration

Post by paulstoffregen »

Regarding "can be bypassed once usb enumeration is complete", perhaps, but the USB spec allows the host to send control transfers for USB descriptors at any time. I know Linux sometimes sends requests to read the string descriptors, so there is at least one case of a major operating system using that capability. I believe Windows pretty aggressively caches everything in the Windows Registry, but Microsoft has made many changes over the years, so who knows?

I'm afraid this is getting pretty far into the specific design of your product. I can't answer every question and I certainly can't guide you on every specific step for you own product design.

pendragon_01
 
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Re: using microcontroller to manage USB host enumeration

Post by pendragon_01 »

thanks for the input

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