I looking to benchmark the Full Speed USB 2.0 capabilities of the LPC-214X. Unfortunately, I’m a newbie at both USB and the LPC-2000 family. We’re trying to make some on-front design decisions. I have the Virtual COM demo up and running on the Keil MCB2140. I also downloaded a free USB Sniffer program. I open 2 hyperterminal windows, and physically connect COM1 on the PC to COM1 on the MCB2140 (a.k.a. COM4). I configure both for 115200, N,8,1 and type away in one window, read the text in the other. If I transmit an entire file all at once, the Sniffer shows all the USB packets that got generated and has timestamps for each packet. The overall throughput ends up being just under 20 kbps for large files. This stinks. I’ll have to hook up a scope, but I’m suspecting Windows isn’t giving my hyperterm window the time of day, and my 115200 message is getting broken up into noncontiguous chunks. I suppose I’ll have to write something that sends a huge burst of data over USB that I can measure with the Sniffer. I’m expecting to see anywhere from 500 kbps to 10 Mbps for Full Speed USB.
I’d say if Bertrik still monitors this site, he would be the man to ask. He wrote the software package called lpcusb, which is basically a USB driver for the LPC214x chips (for the embedded firmware side of things, not the PC), and is becoming increasingly used in the DIY community from what I understand. I would imagine he did similar tests when he was testing out his software.