USB vs RS232

[MiniMe]

Hi !

Due lack of experience I'm having difficulties choosing between USB and RS232. I hope You can help me out.


Project(devise) is a stand alone regulator with some user interface.

Q1: What will happen if connection between devise and laptop PC is made (plugged in) If it is RS 232 a popup window will appear and numbers from devise will start running? For PC usually no drivers needed no matter which OS is running ? But no laptop got RS 232 or RS 485 so converter is needed.

Q2: What will happen if connection between devise and laptop PC is made (plugged in) If it is USB. Microchip drivers are needed and ... more is needed maybe ? ...? What about different PC Operating systems? Can low experienced user handle this kind of tasks?


Any other ways how to connect PIC mcu to a laptop PC ?
Is there chance to use LAN or DSL socket to do RS 232 job ?

The connection between device does happen not very often... 2 or 3 times. For sure it is needed for prototype devise but for final devise it is meant to be as problem solver (as user have feature to see what happened during work-flow of devise).

For sure You have done more and seen so much more that me. What is Your opinion on this matter. Is there a need for USB for final project.



Thank you in advance !

[bkamen]

Your easiest answer to occasional configuration is RS232. RS232 is the simplest and most common way to give a user access to workings on a microcontroller.

Even if a laptop doesn't come with an RS232 port, for about $30, a USB->RS232 adapter is easy to find.

Doing USB on the PIC immediately makes everything harder than with simply using RS232. You have to have a USB "stack" running on the PIC and this increases code size and complexity.

Ethernet/TCP-IP have the same factors. Really cool - but really complex.

Best Regards,

-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D

[asmboy]

google:
USB FTDI SERIAL parts Like UM232R are your friend.

also EDGEPORT converters for PC

[MiniMe]

Thank you !

Replies been really useful.



"USB on the PIC immediately makes everything harder "
I'm intrigued ... maybe you could tell me more ... How much more complex. What are the problems I may face later. What is the main difference between UART and USB communication ( delay, principle complexity ? )


--I've been looking at the example ex_usb_serial. Is this what I'm looking for?
--Is there a Serial to USB "part" that I can just add to a project PCB speed is not important.



Can I integrate USB feature as the last one on pic18Fxx50 part (my case could be 18F14K50 )


Again thank you !

[bkamen]

I could say it like this:

Imagine doing serial over TCP/IP? Sound simple? Of course not!

(I actually wrote a TCP/IP to RS232 bridge for someone recently)

RS232 (as we all know and love) is defined simply as some voltages over a wire clocked in a defined way -- and we have transfer of information (data) from one point to another.

Simple.

USB on the other hand (or WiFi or TCP/IP with Ethernet or PPP or who knows what) is a whole protocol intended to have all sorts of hosts talking over a shared bus (something that typical RS232 is not) signalling all sorts of states, transferring data...

it's a much bigger onion with some busy layers added. (just think of the drivers needed that RS232 needs much less of)

All this for setting a few configs by a user. Not worth it. :D

Spiffy-Neato? -- sure.. but definitely more time/work and hassle.

When RS232 is broken, most of the time you can peek into the problem with a scope or home-made test gear with extra COM ports...

USB -- a lot harder to see into without an analyzer. (You can find free ones... but you need to know a lot more about USB to interpret what's going on)

Regards,

-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D

[MiniMe]

Reply, You made, taught me everything I wanted to know in a way easy to understand. You helped me and saved very big amount of my time.


Thank you once more.