Software – General Concepts
The General USB Process
The Enumeration Process:What happens when a device is connected?
2.Transfer Mode - The host then determines which type of transfer each device requires. There are three transfer modes:
Interrupt Transfer - Devices that send very little data such as mice or keyboards would choose this type of transfer. 64 Kbytes/second transfer rate
TM
Bulk Transfer - Devices that send send data in large packets that need to be verified as accurate, such as printers, would choose this type of transfer. 1216 Kbytes/second transfer rate
Isochronous Transfer- Devices that stream data such as speakers would choose the Isochronous type of transfer. There is no error correction with this transfer mode as with bulk. 1023 Kbytes/second transfer rate
Control Transfer - The host sends commands, and query parameters via control packets. All devices use Control transfers to Endpoint 0 for the Enumeration process. 832 Kbytes/second transfer rate
