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When USB packets are a multiple of MaxPacketSize. Any byte that happens to fall on top of a multiple of MaxPacketSize is corrupted.

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When USB packets are a multiple of MaxPacketSize. Any byte that happens to fall on top of a multiple of MaxPacketSize is corrupted.

‎01-29-2014 05:49 PM
1,247 Views
Jetcitycowboy
NXP Employee
NXP Employee

Using MQX 4.1. and 4.0.3 when the packets are a multiple of MaxPacketSize.  It is ANY byte that happens to fall on top of a multiple of MaxPacketSize.  Which means if you send a packet of 150 characters, the 128th byte magically gets zeroed.  Is there a fix for this?

I am seeing this on 2 different processors KL25 and Coldfire MCF52254CAF66, at 2 different customers

I see a similar posting by Paul Hunt, that has not been addressed.  Please advise.

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‎02-11-2014 03:10 PM
1,086 Views
Carlos_Musich
NXP Employee
NXP Employee

Hi Kenneth,

I assume you are talking about USB Stack 4.1.1 and 4.0.3.

Are you using host or device?

Do you see the same behavior in the 64th byte?

Are you using one of our examples (which one)? Did you edited it? Or you are developing your own application.

Please be sure that the device maximum packet size is set to 64 for Interrupt, control or bulk transfers as indicated by the spec. Setting max packet size higher than 64 can cause unexpected behavior. Isochronous transfers can be up to 1024 but I think this is not your case.

Regards,

Carlos


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