The maximum speed for the interrupt transfer for USB 2.0 full speed is 64kbytes/s. LPC2148 is used in device side. Is there a possibility of increasing the interrupt transfer speed by increasing the packet size. In that case generic device class wont support the device. Is there any possibility of moving to custom hid driver
Bulk transfer?
Hello Westermark,
Thanks alot for your reply. In the bulk transfer guarantied time delivery is not there. In case the bus is busy there will be delay as there is no reserved bandwidth. Our application demands both time and data correctness. In the books and websites the maximum speed possible for the interrupt transfer was found to be 64 kbytes/sec per end point. The core used is LPC2148 which gives 5 interrupt IN endpoints. So maximum speed possible 320kbytes/s. But more speed is demanded for our application. Currently HID device class driver is used which supports interrupt transfer.Is there any possibility of increasing the maximum packet size from 64bytes? I tried increasing the packet size but the enumeration fails. If i go for a custom driver in host side will my problem solved? Please suggest me a solution for this.
Two things.
1) Who would claim your required bandwidth? Just make sure that you don't connect through a USB hub and no other device should be there to steal bandwidth on the cable.
2) Firewire allows allocation of way more bandwidth. Yes. Much more expensive. But you get what you pay for. If you do not want to take the cost of a bus designed to allow you to allocate x Mbit/s of dedicated bandwidth, then you will have to settle for what you can get from the standards you do pay for.
3) Or you may look into ethernet together with QoS.
Hello Westermark, Thanks for the reply. The problem in using bulk trnsfer is that application will be tested in the stress condition loading the PC with many other applications and it is expected to meet both guarantied data and time. Thats why the interrupt transfer was chose. So your opinion is the maximum packet size cannot be increased from 64bytes for interrupt transfer in any method? Our present scope is using usb 2.0 full speed only. Your suggession will be very helpful to me.
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