Method for data transfer between host and device
View Patent ↗The present invention relates to a method for data transfer between a host and a device as well as to respective apparatus. A host is seen as a communication apparatus which organizes data traffic. A device is seen as dependent on the host. In a tiered-star topology there are usually multiple devices connected to one host. A method for data transfer between a host and a device through pipes is presented. The available memory in the host is divided into multiple segments. The assignment of segments is changed between pipes in dependence on the pipe traffic.
1. Method for data transfer between a host and a device through pipes wherein an available memory in the host is divided into multiple segments, the method comprising assigning a segment of memory to a control pipe, identifying a mode of data transfer, determine a number of input pipes and output pipes to be established if a bulk transfer mode is identified, and assigning each memory segment to at maximum a single pipe at one time, wherein at least one memory segment is allocated to and shared by at least one input pipe and output pipe pair, and the allocation of the at least one memory segment is switched between pipes of the at least one pipe pair upon detection of a change in transmission mode, and wherein all memory segments assigned to the at least one pipe pair are assigned only to the output pipes or only to the input pipes of the at least one pipe pair at one time, and wherein if a memory segment ahead assigned is available for a new pipe to be established with a new endpoint, a flag indicating a number of pipes have access to the memory segment already assigned is increased by one.
2. Method according to claim 1 , wherein bulk transfer mode is used.
3. Method according to claim 2 , wherein one or multiple flags are added to each memory segment indicating to which pipe the memory segment is currently assigned.
4. Method according to claim 3 , wherein a separate flag is used to tell to which device the memory segment is assigned to and another flag is used to tell how many pipes have access to said memory segment.
5. Method according to claim 4 , wherein memory in the host is allocated to a bulk in pipe in case of communication from a device to the host and to a bulk out pipe in case of communication from a host to a device.
6. Method according to claim 3 , wherein memory in the host is allocated to a bulk in pipe in case of communication from a device to the host and to a bulk out pipe in case of communication from a host to a device.
7. Method according to claim 2 , wherein memory in the host is allocated to a bulk in pipe in case of communication from a device to the host and to a bulk out pipe in case of communication from a host to a device.
8. Method according to claim 1 , wherein one or multiple flags are added to each memory segment indicating to which pipe the memory segment is currently assigned.
9. Method according to claim 8 , wherein a separate flag is used to tell to which device the memory segment is assigned to and another flag is used to tell how many pipes have access to said memory segment.
10. Method according to claim 9 , wherein memory in the host is allocated to a bulk in pipe in case of communication from a device to the host and to a bulk out pipe in case of communication from a host to a device.
11. Method according to claim 1 , wherein in case of multiple in pipes or multiple out pipes, memory in the host is allocated to a specific in pipe or a specific out pipe depending on the traffic within certain pipes.
12. Method according to claim 11 , wherein the assignment of the at least one memory segment is switched between the multiple in pipes or between the multiple out pipes.
13. Method according to claim 1 , wherein the whole memory is segmented and all memory segments are assigned.
14. Method according to claim 1 , wherein one or more memory segments are used as buffer for control transfer exclusively.
15. Method according to claim 1 , wherein the data transmission is an USB transmission.
16. Apparatus with data transfer means to establish communication with another device through pipes wherein an available memory is divided into multiple segments, a segment of memory is assigned to a control pipe, identifying a mode of data transfer is identified, a number of input pipes and output pipes to be established is determined if a bulk transfer mode is identified, and each memory segment being assigned to at maximum a single pipe at one time wherein it is further provided with change in transmission mode detection means and switching means for assigning and sharing at least one memory segment to an input pipe and output pipe pair and changing assignment of the at least one memory segment between pipes of the at least one pipe pair upon detection of a change in transmission mode such that only the input pipes or only the output pipes of the at least one pipe have memory segments assigned to them at one time, wherein if a memory segment already assigned is available for a new pipe to be established with a new endpoint, a flag indicating a number of pipes have access to the memory segment already assigned is increased by one.