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AT90USB1287 OTG host compatibility with devices?

Hi,

I would like to discuss with anyone who has some experience interfacing the AT90USB1287 to various USB devices.

Have you found any that don't work?

I have two devices which are detected correctly - Lexar 32MB jump dirve and a Lenovo USB sound device .... I have two that are don't get detected correctly and they are a 512MB Imation flash drive and a Gigafast 102.11g wireless fob.

The code goes screwy in this section when one of the "bad" devices is plugged in (snippet from the atmel demo programs)

case DEVICE_UNATTACHED: for (c=0;c

Reply to
rg.jones
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Am I the only one using the AT90USBKEY for host mode? ;)

It appears that plugging in some devices and attempting to apply power causes the AT90USB1287 to reset.

Can any one confirm if this is a known problem?

Glenn

Reply to
rg.jones

We are getting a prototype board for the chip, but not ready yet.

Probably watchdog reset.

It sounds like a software issue.

Reply to
linnix

Hi Thanks for the reply ...

I don't think it is the software as some devices work okay ... It appears as if the mcu is being reset when vbus is being applied - I am going to check the descriptors (of the problem devices) for their power requirements.

Glenn

Reply to
rg.jones

Works Lexar 32 MB Flash drive - 90ma Lenovo USB Sound device - 100ma Microsoft Optical mouse - 100ma

Doesn't work Imation 512 MB Flash drive - 200ma Trendnet 424UB 802.11b/g - 400ma GigaFast WF748-CUI 802.11b/g - 500ma

Glenn

Reply to
rg.jones

So, are they exceeding the power requirements?

100ma is the typical default.
Reply to
linnix

More important`: How much can your power supply support?

--
Best Regards,
Ulf Samuelsson
This is intended to be my personal opinion which may,
or may not be shared by my employer Atmel Nordic AB
Reply to
Ulf Samuelsson

USB OTG specification says max power is 30mA so if the circuitry is made as per requirements of the USB OTG it doesnt have to deliver more than 30mA, it may deliver more but it really isnt required. If you are using non-OTG devices then check the power supply

Antti

Reply to
Antti

Atmel suport indicated that the devices that don't work most likely exceed the 100ma spec for current at enumeration time. OTG spec 8ma should be available at enumeration time.

They offered two work arounds

1) Disable the BOD fuse (by default it is set to 2.6V) 2) Add a capacitor (~22=B5) to the regulator

I have done step 1 so far and that allows the devices I had an issue with to enumerate.

I am also using a 12v (1000ma) power supply (just what I happended to have on hand)

Hope this helps someone else.

Glenn

Reply to
rg.jones

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