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How to accept the character in PIC 16F628A

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nck

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pic16f628a usb

Hello everybody
I want to make one project that support to my Master programme.
That project is PIC (16F628A) accepts the every character from usb and display on the LED matrix array .The character display is at least 10 character and more than.So how to accept the character .
Can anyone help me and Thanks.
 

taitsoft

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pic16f628 usb

First off, a 16F628A can't accept a character via USB directly. You can solve this by using a USB-to-serial adapter cable or by using a USB-to-serial chip like the ones from FTDI (http://www.ftdichip.com/). Now life is simple because this setup is really no different than getting characters from a native serial port and that's very easy. Another fun way of doing it is to add a Bluetooth module to your display board and use it to communicate with a USB Bluetooth dongle (A BT dongle is dirt cheap and Google might turn up a local source for an inexpensive BT module or get this one from SparkFun: http://www.sparkfun.com/commerce/product_info.php?products_id=582). Using BT is just like using a serial port too. I have a sneaky feeling this is not what you wanted to hear though.

If you really do want to interface a PIC to USB directly then use a different PIC; there are at least two families of PICs which provide USB capabilities. Again, I have a sneaky feeling you don't want to hear this either.

If you don't accept the solutions I have put forward, and really do want to press ahead with a direct 16F628A to USB connection then I wish you the best of luck. I just don't think your PIC is fast enough to keep up with even the slowest of the USB protocols. To convince you, just have a look at what a close thing it was to get a much faster microcontroller to talk USB:

http://www.obdev.at/developers/articles/00003.html

David
 

nck

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usb pic16f628

Hi taitsoft;
Thank you very much for your kindness!Fortunately, I have a USB -to -serial adaptor cable.And i also want to know the source code for this and I want to store the character from PC software in PIC's Data memory.
Thanks a lot .
 

taitsoft

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16f628 usb pic projects

You've got a USB-to-serial cable! You could have said that! :)

You don't say what language you are using to program your PIC so I assume you are writing assembly code. A bit of googling is all you need to turn up some relevant examples.

These two related pages show you how to use the 628's hardware USART, both are for 9600 baud using a 4 MHz clock. The second example implements a character buffer.

http://www.oz1bxm.dk/PIC/628uart.htm
http://home.publishnet.nl/~hragas/electronics/usart/usart.html

By data memory I guess you mean the on-board data EEPROM rather than RAM. I was going to refer you to the datasheet as that describes all the hoops you need to jump through to access this area, but a Google search showed that many people were having trouble getting those routines to work with the 16F628A. Here's a couple of archived PICLIST discussions I found:

http://www.embeddedrelated.com/groups/piclist/show/7337.php
http://www.embeddedrelated.com/groups/piclist/show/4768.php

Visit Microchip to grab the latest 16F628A datasheet and make sure you check for any errata sheets that might apply to your silicon.

Good luck with your project.

David
 

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