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RE: [AVR-Chat] Avr ISP

2004-03-12 by Cobb, Quentin

I assume you mean AVR-ISP and STK500 :)
The AVR is nice in that you need very little in the way of external support components. things are simple with the internal oscillator: +5V, a resistor to pull reset high, connections to the power & ISP pins and you're away.
You will need a cable/adapter (often called a programmer) to connect the ISP pins to the computer parallel or serial port, and software to talk to the programmer (also often called a programmer)
The STK500 can be used as an onboard programmer or for external ISP programming. I.e. you can plug the chip into a socket on the STK500 to program it or you can connect the STK500 to your ISP connection in the target board.
The BIG advantages of having an STK500 are that:
1) You have a known-good environment - if you can program the AVR in the STK500 but not your circuit then your circuit is faulty.
2) You can experiment with the LED's and switches and sort out the whole programming thing, without having to reach for a soldering iron until you're ready.
2) If you program yourself out of the AVR by mis-setting a fuse - (EVERYBODY does this at least once) - you can recover the chip by putting it into the STK500. For example the most common mistake is to program the fuses in reverse, a "set" fuse is "0" not '1" It;'s really easy to program the AVR to use an external oscillator and if your circuit doesn't have one you can't reprogram the chip. If you have an STK500 you merely say "whoops" and plug the AVR into the STK500 and re-program it properly.
The advantage of just using an ISP programmer/cable is that they're cheap, simple and portable. You can get away with just a DB25 plug, short length of wire & 4 resistors.
Q
-----Original Message-----
From: Capricon [mailto:capri5@nethere.com]
Sent: March 12, 2004 5:47 AM
To: AVR-Chat@yahoogroups.com
Subject: RE: [AVR-Chat] Avr ISP

What are the advantages of having ASP_IVR over just having an STL_500?
Capricon

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