| ??? 10/02/04 19:55 Read: times |
#78584 - RE: WEOT: USB implementation. Responding to: ???'s previous message |
Prahlad J. Purohit said:
I wanted to know have you guys tried... Hitting that 'Search' button would have shown you all that's been said here alread about USB on 8051s - and it's quite a lot! Prahlad J. Purohit said:
implementing USB by software bit banging if yes how did you do it? You must be joking - we're talking mega bits per second here!! And that's just the physical layer! The protocol stack is not a thing for an 8051! Prahlad J. Purohit said:
Are there other cheap alternatives for implementing soft USB? There are several 8051 derivatives now with integrated USB; eg, Si Labs (nee Cygnal), TI, Cypress,... http://www.keil.com/dd/parm_search.asp And then there are the external USB chips; eg, from FTDI. Here's one I prepared earlier: http://www.antronics.co.uk/usbmod2 Note that USB is not a peer-to-peer connection; you need a Host and a Device function to communicate - you cannot simply connect two Device functions together! Typically, the 8051s with USB, and the USB chips are Device functions; PCs and the like are Hosts. The software requirement for a Host is significantly greater than for a Device. Cypress have a device for giving limited Host functions for embedded systems - I think Erik's been working with them (the 'Search' would show you). USB On-The-Go (OTG) offers both Host and Device functions in one unit... |
