Hi guys,

Just a follow up about this issue...

I got help from Microchip Forums (newfound), see this thread:
http://www.microchip.com/forums/m569370.aspx

It appears 18F27J53 USB RAM structure isn't handled by current USB
libraries. Compare figure 17-5 page 173 for 18F4550 datasheet vs. figure
23-4 page 387 for 18F27J53 datasshet for instance. USB libraries assume
USB_BASE_ADDRESS as the beginning of USB RAM, corresponding to the Buffer
Descriptor Table, and refers actual buffers relative to this address. This
is not true for 18F27J53, though indeed, as newfound mentioned in one this
last post, last available bank still contiguous and should be used like in
18F4550.

Hope what I'm talking about makes sense to someone, I'll try to fix this,
but I'll appreciate any help :)

Cheers,
Seb

2011/3/27 Sebastien Lelong <[email protected]>

> Thanks Kiste for your input. I indeed once had troubles with USB serial
> with ttyACM0 device, it required kernel >= 2.6.32 to deal with CDC protocol.
> But in this case, I don't think this is the case, as in the end, kernel
> doesn't want to do anything with my device, and it doesn't attach any
> /dev/ttyACM0. I would have seen it in the log anyway.
>
> I'll on another PC to see if it behaves the same.
>
> Cheers,
> Seb
>
>
> 2011/3/27 Oliver Seitz <[email protected]>
>
>>
>>
>> >- under Linux, plugging the board gives the following in /var/log/syslog
>>
>> I've tried USB some time ago, and I got similar messages with too old
>> kernels. And too old means anything before 2.6.32, I think.
>>
>> Sometimes there are some messages even with newer kernels, but a device
>> like /dev/ttyACM0 shows up, and it works.
>>
>> Greets,
>> Kiste
>>
>>

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