I am working with a custom K64 system. It is to be used in a laboratory measurement system that generates a lot of data. If results were sent as 32b ASCII values, it would take a minimum of 160KB/s. There is at most 64K of the K64's RAM available to buffer measurement data, so that puts an upper limit on response time and throughput at the host. I am planning to use the USB interface, but the question is what type of device it should present to the host.
CDC-serial would be easy enough to work with, but I don't know if these rates would be doable. Maybe it is doable on the K64 but not on the PC side. Anyone with experience doing this ?
What about the virtual NIC using the RNDIS demo ? In this case the K64 would have to be the termination for communications, and not just forwarding to an Ethernet port as in the demo. This seems potentially interesting, but I don't know enough about RNDIS to anticipate what other support would be required. Can anyone say if this would be a practical form of communication ? And if so, any tips on how to connect from Windows, how to exchange messages, etc would be most appreciated.
MSD seems possible but it really doesn't suit the need well. Maybe the host would attempt to read a huge file, and the K64 would return measurement data at the speed that it becomes ready.
A fully custom solution would easily support the need but there is no time or stomach to support development of a USB driver on the PC side.