USB Protocol

[Iceman_Chris]

Hi,

I am used to using RS232 with my PICs but since USB ports are all almost all new PCs I thought I should probably switch to using USB for computer-to-chip communications. I know there are alot of chips out there that could probably do everything but what does one need to do code-wise on the PIC to have a USB interface. One more thing, a USB port has four connections I believe, +5V (I think), GND, then DATA+, and DATA-. What are the DATA +/-s?

Thanks in advance, Chris.

 

[Nigel Goodwin]

Hi,

I am used to using RS232 with my PICs but since USB ports are all almost all new PCs I thought I should probably switch to using USB for computer-to-chip communications. I know there are alot of chips out there that could probably do everything but what does one need to do code-wise on the PIC to have a USB interface. One more thing, a USB port has four connections I believe, +5V (I think), GND, then DATA+, and DATA-. What are the DATA +/-s?

Thanks in advance, Chris.

There are a number of PIC's that have USB interfaces, it's ESSENTIAL that you use one of those (preferably the new 18F ones, as they are FLASH - the others are OTP). You can download datasheets are application notes from MicroChip, including full details of the PICKIT1 USB PIC Programmer. USB isn't practical (or possible?) in software alone.

Be prepared for a shock though - on a scale of 1 to 10, if RS232 difficulty is 1, then USB is probably 30-40!.