> On Wed, Sep 26, 2001 at 10:19:44AM +0800, Christine M. Yusingco wrote: > > Has anyone out there written a device driver for the SA1110 implementing all > > four USB transactions? the SA1110 only supports bulk and control transfers, > > would it be possible to implement isochronous and interrupt transfers on the > > sa1110? > > Read the SA1110 manual, the SA1110 only has bulk and control endpoints, > no isochronous and interrupt endpoints.
An interrupt endpoint is a matter of semantics; it's a bulk IN (ie slave->host) that you define as an interrupt endpoint in the endpoint descriptor. The host will "poll" it (sending an IN token) at the rate specified - if you load something into the endpoint fifo, it will get sent when the host next polls. I'm not familiar with the SA11x0's onboard USB slave, but I'm pretty sure that an interrupt endpoint can be defined. Isochronous EPs are different, as they do not have the usual handshaking (no ACK packet - if it gets corrupt, it's just lost; seeing as isochronous transfers send/receive a fixed size packet every frame and are time-critical, this isn't generally a problem). If the SA has no isochronous mode setting, the hardware isn't capable of operating in this mode. Hugo _______________________________________________ http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm Please visit the above address for information on this list.
