USB: Schematic for PIC16F877 and USBN9604

Prashant Patel · Joined: 19 Jul 2004 Posts: 33

Hi..

I want to use USB in our next project. And decided to use

PIC16F877 and USBN9604. I know there are some example

programs given with CCS C Compiler. But I am not sure

how PIC16F877 and USBN9604 should be connected to work

this program(might be ex_usb_hid.c) . Can any body send

schematic for this which might be provided by CCS..??

Thanks...

Regards
Prashant

lucky · Posted: Wed Jul 21, 2004 1:57 am

Dont know about the USBN9604 but FTDi do 2 realy simple IC's. One is Parallel (FT245) out & the other is RS232 out (FT232). Perfect for PIC's.
_________________
Lucky
www.mpic3.com - MPIC3 player project, Forum, Downloads, Online Shop

alexz · Joined: 17 Sep 2004 Posts: 133 Location: UK

treitmey · Joined: 23 Jan 2004 Posts: 1094 Location: Appleton,WI USA

look for USB schematics here for the FTDI chip... GREAT examples.. even how to use a FET to power other USB devices...
http://www.ftdichip.com/FTProject.htm
http://www.ftdichip.com/FTSchema.htm
http://www.ftdichip.com/FTSchemaArchive.htm

I think the FET example is in the archive.

Good luck.

I have two FULL PRODUCTION products useing these chips.
They are reliable.
tjr

alexz · Joined: 17 Sep 2004 Posts: 133 Location: UK

Trampas · Joined: 04 Sep 2004 Posts: 89 Location: NC

I use SMT parts all the time, actually most of my devices I stay away from through hole parts. The largest surface mount part I have used is a 288 pin quad flat pack. All the SMT devices I solder by hand, I can solder a 288 pin QFP FPGA in about 2 mins. The whole trick is to use a soldering iron with a "mini-wave" tip.

Surface mount parts are simple and easy to solder by hand, the PCBs are often cheaper and smaller than through hole designs.

Trampas

Mark · Joined: 07 Sep 2003 Posts: 2838 Location: Atlanta, GA

And when you make them yourself, you don't have to drill the holes Very Happy

Trampas · Joined: 04 Sep 2004 Posts: 89 Location: NC

I personally find that I can order PCBs cheaper than making myself. For example I usually order 20 2 layer prototype PCBs for about $250. I find that 6 layer PCBs are about $800 for 20 boards.

My 2 layer boards usually have about 100 vias, will some of my 6 layer boards have had close to 1000 vias. Thus CNC milling or manual etching would be a pain...

The funny thing is get lots of quotes for PCBs, I usually do one a month. However none of the "cheap" PCB houses in back of the magiznes never have given me a cheap quote, usually they are 2-3x more. It seems that their low price boards never meet my requirements, I have slik screening on both sides. Additonally a couple of times I have had boards which meet their requirements and still did not get the cheap price, when I asked why not they informed me that I had to order through the web, rather than email to get cheaper pricing.

Trampas

bdavis · Posted: Thu Oct 14, 2004 9:08 pm

Trampas-

What is the mini-wave tip? ie: what mfg and what size? I have done many 0805 type caps and resistors, but find the fine pitch smt packages a bit scary to solder.

Also - could you post a few of the pcb houses that you have found good to work with with price?

Thanks!

Mark · Joined: 07 Sep 2003 Posts: 2838 Location: Atlanta, GA

We have a Hart Solder Station. For soldering fine pitch, you can't beat it. Takes about 13-18 seconds to solder a 64 quad flat pack. I also have a nice high power microscope. If you have a steady hand, you can solder just about anything.

Trampas · Joined: 04 Sep 2004 Posts: 89 Location: NC

The mini wave tip is a soldering tip that is shaped like a horse's hoof. This causes the solder to be drawn into the cup. The way you solder fine pitch parts is that you put a small amount of solder on the iron. You then use some liquid flux on the part. Then tack the opposite corners on the part. Now slowly drag the soldering iron over the pins. It is amazing the first time you see it done, but it works great.

The soldering iron I have is a Pace ST145.

As far as board houses go, create your Gerber files and then send them to every board house you can find through a google search. Personally I have found that:

WWW.imagineering-pcb.com - good for 2 layer PCBs
www.parlin.com - Great for multi-layer PCBs.

I will warn you that the PCB market is funny in that you have to be careful as that I have gotten quotes for one board that are $2k-$3k different. So get a lot of quotes.

Trampas

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

Trampas · Joined: 04 Sep 2004 Posts: 89 Location: NC

The No Touch PCBs Look promising I might give them a try!

Thanks!!!
Trampas

MGP · Joined: 11 Sep 2003 Posts: 57

I've been using these guys lately for 2 and 4 layer proto boards:

http://www.pcbfabexpress.com/

No problems with the last 4 jobs they've done for me, the price and quality of the boards has been excellent.

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

I saw that website too, when I was looking for low cost boards. Their
FAQ sounds like it was written by the same person who wrote the FAQ
for the 2justforyou website.

Their street addresses are only 38 numbers apart:
http://www.pcbfabexpress.com/contactus.jsp
https://www.2justforyou.com/NASApp/sierraproject/jsp/tabs_contactus.jsp
It makes me think they are the same company.