AVR Selection help

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#1
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Hi,

I'm new to AVRfreaks and AVR in general. I'm doing a project and I can't decide which AVR is right for me.
Here is what I want to do:

- Have a simple user interface with a small LCD panel and keypad

- Send input to an Analoge Devices arbitrary waveform generator.

The final product is going to be an amplifier. All I need the AVR for is to set up the waveform generator, and to do that I need a user interface that I would like the AVR to also implement. The waveform generator uses a 32 bit memory address, so I thought it would be better to use the 32 bit version of the AVR.

I was looking at the AP7, but the ball grid array scares me a bit. I've never built a PCB for something like that. Are there open-source PCBs for it maybe?

The UC3 looks easier to use, but I'm not sure if I could implement a user interface on it easily.

Thanks for your help,

Waspinator

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You can use an 8 bit AVR with four ports and compute the 32bit address/data in software. Also it is possible to "add" 8 bit ports by using latches like 74ls573 and control it by software.

Since your application does not require much processing power, I don't think you'll need an AVR32.

Btw, why the generator inside the amplifier? Test equipment?

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Thanks for the reply Heihopp.

I was looking over the 8 bit AVR chips since, and there seem to be many. Most of them with some specific functions like USB, LCD or automotive. Would have any suggestions as to which one is the most general purpose?

Just a few extra questions

1. Could I have a single chip controlling the LCD panel, a use interface and the programming of the waveform generator?

2. How large of an LCD can I control with the 8 bit? Could it be VGA or am I limited to 4x40 segment screens.

3. What are the disadvantages of choosing a 32-bit AVR over the 8-bit. Is it easier to program the 8-bit?

The most important quality I'm looking for is for the programming and implementation to be as quick and easy as possible. I hope that drivers for LCD's, keypads, and USB are available and easy to implement. Would there be an easy way for me to reprogram the chip once it is already implemented if for some reason I wanted to add more features in the future?

The generator and amplifier will be used for experimental medical imaging equipment.

Thanks again.

Waspinator

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It really depends on what you want to do.
It will be hard to drive a colour LCD panel with VGA resolutions with a 8-bit AVR. Maybe you can generate signals with the pins, but I am not sure about it. I guess there would not be much graphic capability with 8-bit AVR in picture, maybe some text.

Driving a alpha-numeric LCD panel would be OK with the 8-bit AVR and the AVR32. But, the LCD cannot be a deciding factor between the AVR and the AVR32. Selecting the AVR32 just to drive this LCD would be an overkill. Of course, I am assuming the LCD panel has an in-built controller. These are easier to program than the ones without the controller.

You do mention USB interface. What do you want to do with the USB interface? Do you want to connect it to the PC to retrive data from your system or act as a USB host?

I have used and am using the AVR32 devices, but have never used the 8-bit AVR.

I think the AVR forum is a better place to have this thread. You are likely to have more feedback on which AVR to use, the 8-bit or the AVR32.

-drt