interested to set up the USB module using PIC18F450

could anyone here assist me in searching for the codings in assembly manguage preferbly....for creating a USB module with the PIC?

I wanted to use PIC16F877a to connect with the serial USB... but was told it's very troublesome.or impossible.
is that true?

to connect any PIC to USB is under the UART protocol right? or was it i2c?

I am very immature in my knowledge of the elctronic world. but am an avid learner.

Would really want to learn from this site earnestly.

many thanks,
slurp

U S B is essentially a serial protocol . But the data transferring is in differential. In Usart the data is understand with reference to ground. So you first need a usb host. Otherwise you can chose pic 18f4550 it already contain an usb client. It is pin compatible with pic16F877

thunderboympm said:

U S B is essentially a serial protocol . But the data transferring is in differential. In Usart the data is understand with reference to ground. So you first need a usb host. Otherwise you can chose pic 18f4550 it already contain an usb client. It is pin compatible with pic16F877

Click to expand...

Hi thunderboympm, thank you for your reply.
USB host? What do you mean? Because from 16F877a i saw i can go for MSSP or USART.
are you saying that USB = serial protocol = use USART??

Any good and helpful links you could share with me. please?

I am very lost at this.

many thanks,
slurp

No USART it totally different to USB.

Thunderboy was saying that you should use a PIC with a built-in USB host. It is a lot of work to do USB in software otherwise.

Have a look at the 18F4550, as it has built-in USB.

thunderboympm said:

U S B is essentially a serial protocol . But the data transferring is in differential. In Usart the data is understand with reference to ground. So you first need a usb host. Otherwise you can chose pic 18f4550 it already contain an usb client. It is pin compatible with pic16F877

Click to expand...

Hi thunderboympm,
glad to receive your reply. What do you mean by havng a "usb host?"
I would like to use PIC16F877a.
Therefore, I am assuming the components I will be needing are,
a PIC16F877a , a cable with one end having the USB head...

I have surfed through the internet and found that some people commented using max232 or rs232...hwo is that so?

hoping to hear from you soon.

cheers,
slurp

Gobbledok said:

No USART it totally different to USB.

Thunderboy was saying that you should use a PIC with a built-in USB host. It is a lot of work to do USB in software otherwise.

Have a look at the 18F4550, as it has built-in USB.

Click to expand...

hi Gobledok...
glad to hear from you...

i know thunderboy is asking me to use PIC18f4550..but I am assigned with PIC16F877a...
I believe there should be a way to it right?
using 16F877a? please?

cheers,
slurp

Hi slurp have a look at **broken link removed** It uses a USB IC to interface to the USB bus.

Though I don't know a lot about USB, so I'm probably not the best to ask

slurp.lolipop said:

i know thunderboy is asking me to use PIC18f4550..but I am assigned with PIC16F877a...
I believe there should be a way to it right?
using 16F877a? please?

Click to expand...

Not really - use an FT232 to convert from USB to serial, and connect the PIC via serial. Or just use a USB/Serial lead, which will probably be cheaper.

If you want 'real' USB use one of the 18F series that have USB support in hardware.

slurp.lolipop said:

hi Gobledok...
glad to hear from you...

i know thunderboy is asking me to use PIC18f4550..but I am assigned with PIC16F877a...
I believe there should be a way to it right?
using 16F877a? please?

cheers,
slurp

Click to expand...

USB is complex. For this reason microchip provides the USB stack (code) and it is written in c. Microchip also provides micro controllers with built in USB hardware.

If you have a boss asking you to do this I doubt he understands what he is asking. If it is a school assignment good luck.

Try here

Go to Microchip Forum - USB.

Search for an old thread started by Brad Minch where he posted about implementing USB in assembler.

It is, by far, the longest thread in the USB forum and basically worth the effort if you really want to approach an Assembler implementation.

I personally did and built the circuits for each "lab" using the 18F4550.

Point is that, besides spending LOT of time you have to be prepared to continuous after that, mostly on you own.

When you managed to understand the basics, look for the posts of another member, Olin Lathrop, who implemented a working design fully in Assembler. IIRC he posted software or links to it.

Sure you will spend time.

Just a suggestion: prior going there read the basics somewhere else.

Buena suerte. You will need it.