Start with USB

[patroclus]

Hello,
I' ve been doing some work on paralel port, but I wonder if it is time to start using USB. Any good place to start of?
What I really like doing is circuit controlling and data adquisition through USB.

anyway I read that USB speed is even lower than EPP's or ECP's paralel port... in this case, it is less interesting to learn how to use it, knowing how to use paralel port already... any advices?
thanks

 

[Exo]

It is MUCH! more complicated to use USB then using the parallel port. But if you realy want to get into it, there's an application note on microchips website for a USB pic programmer, wich exaplains usb.
you could also google for "usb specification".
In any case, you're going to need an advanced microcontroller to interface with it.

USB1.0 is slower then EPP and ECP, USB2.0 is way faster.

 

[checkmate]

I spent roughly 3 months, starting from reading of USB specs, coding the firmware of a usb device, to the development of a WDM USB driver. A fully customized USB pipe is no mean task indeed.
But of course, there are always short-cuts, like USB-to-Serial convertors, device class drivers etc.

 

[patroclus]

USB 2.0 is the one running at 15 Mbps ??
In real world it never gets above 700 Kbytes / second. EPP/ECP is most of times equal or faster.

 

[Exo]

It can go as fast as 15Mb/sec, but the device on the other end has to support it.

 

[zero_signal_69]

what would be the best/cheapest way to use usb for data acquision. I am looking to collect data (on/off) from a bunch of sensors, and process them with software. I have looked into the cypress usb chip (something one one of these **broken link removed**) but the programmer is about $100, a little over budget for my project.

 

[Nigel Goodwin]

what would be the best/cheapest way to use usb for data acquision. I am looking to collect data (on/off) from a bunch of sensors, and process them with software. I have looked into the cypress usb chip (something one one of these **broken link removed**) but the programmer is about $100, a little over budget for my project.

There's a PIC available with in-built USB, the 16C745, but it's an OTP chip - however, a FLASH USB PIC is due out any time.

Failing that you can use an RS232/USB converter, and run your project as RS232 - this is a common way of doing it!.

 

[bryan1]

If you want to get into usb I suggest firstly looking at www.dontronics.com as Don has not only products like usb-rs232 converters but also a heap of info and links to even more. Anyway as for buying on the net or finding information try the link above and I'm sure you won't be disappointed.

Cheers Bryan1

note: this isn't an advertisment for Don I just find his site an insipiration to electronics especially the simmstick