Why this? USB 1.1 covers low speed and full speed, USB 2.0 additionally high speed devices. So USB 1.1 shoud satisfy your needs concerning a full speed device.
I am using 18F4550 with USB1.1 port at full speed with CDC firmware - no problems.
Same board work on USB2.0 ports.
You don't need USB 2.0 to run full speed.
You need USB2.0 for high speed devices only.
As far as I know, there are some electrical difference between USB 1.1 and 2.0. As you can see, USB 2.0 also support Full speed and it's backward compitable with spec 1.1. Many companies usually say that they meet spec 2.0 even only support full speed...
As everybody here said, it has nothing to do with the USB version. Both v1.1 and v2.0 support full speed communication.
There are many reasons, that I think might caught you. Here the checklist:
1) Did you wire D+, D- line correctly? I have seen someone had the same problem as you described when D+ and D- lines are wired mistakenly.
2) Did you use internal pull-up? Then did you enable internal voltage regulator? Had a capacitor connected to VUSB pin? Again I have seen someone had this problem when the capacitor was missing.
Re: pic18f4550, Full speed 12Mbps?How can I achieve?
Hi,
How did you achieve 12Mbps speed in PIC18f4550?I have implemented the USB serial protocol. But not not getting that speed. I am getting only 2k. What it is happening please reply.