Hi, I have a Omapl138 board, I am trying to connect a USB to the same. M using windows 7 OS. while I am debugging USB firmware code I can see a the following sequence of Signal transfer.
1. a Reset signal 2. device descriptor request 3. set address request
again the same pattern repeating for 4 times.
can anybody help to find why its not come out of these sequence..?
I should get a device confg request next right..?
> I should get a device confg request next right..?
Windows7 in this sequence. - Bus reset - Get_Descriptor(Device) - first 8 bytes - Set_Address - Get_Descriptor(Device) - full size - Get_Descriptor(String) - first 2 bytes - Get_Descriptor(String) - full size - Get_Descriptor(Config) - first 4 bytes - Get_Descriptor(Config) - full size ...
Anyway, your firmware should not "expect" the next request. Your firmware should respond to any request properly, corresponding to the device stage.
> again the same pattern repeating for 4 times.
it may fail at the status stage of set_address OR Get_Descriptor(Device)
Are you making your own stack? or playing on an existing stack like Linux gadget?
Tsuneo
Yes I am using a existing stack. And I am getting the sequence like
> reset > Get_Descriptor(Device) > reset > Set_Address > reset .... and again repeating the same pattern.
I have a doubt for the first Get_Descriptor(Device) request my stack sending 18bytes of data. will it cause any problem..??
Thank you.
After first 8 bytes of Device Descriptor Windows host will terminate further reception of IN packets by sending OUT zero length packet, and after this anyways bus will be reset.