AVR-ChipBasic2 (Mega644)

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The next generation of my single chip BASIC computer. It use a Mega644 with 20MHz crystal and provides many new features such as graphics modes and a little Dataflash filesystem.

https://www.avrfreaks.net/index.p...

Currently DE and US keyboards are supported but there is a third selectable layout which can be coded (by me)to any country specific. There are also about 64 free cells in the character table (10x6) which wait to fill with some content.
An english documentation is in progress but may take a while, any help would be appreciated (LaTEX files).

Joerg

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Very interesting :)
You could save the 3 pullup resitors by enabling the internal pull ups. A HUGE saving :lol:

I guess the 20MHz is mandatory for the video??

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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I have used external pull ups because the internal ones are switched on and of while displaying video. So I think external pull-ups are a better solution and not too much expensive.
The 20MHz is mandatory for video, the (older) mega16 and mega32 versions use only a 16MHz clock but have less capabilities in displaying video.

regards

Joerg

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Quote:
the (older) mega16 and mega32 versions use only a 16MHz clock
So HOW BIG is the code? Will it fit into 16 or 32K now? I have a few boards with 16M and a M324 board with a 18.xxM clock.

I guess I could try it on the STK500....don't understand German too well (in fact nothing)..that's the reason for the silly questions. :?

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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There are several (older) versions for the mega16 and mega32. Both wor with 16M clock. They will be find at the berlios download site which can be reached from my project site ("Download"). If You select "show all project files" You'll find files with "-m16" and "-m32".
The mega16 version was my first try and can store only one program (20 lines) in internal EEPROM. An external I2C EEPROM (24C64) holds up to 16 programs. Next step was the mega32 version which can store up to 4 programs (51 lines) in Flash.
The hardware is mostly the same for all versions, only the crystal frequency was changed to 20MHz for the mega644 and the program EEPROM is not used except at the mega16 version. So You can use the better circuit diagrams of the mega644 version.

regards

Joerg Wolfram

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Quote:
So You can use the better circuit diagrams of the mega644 version
But does the code go over 32K ie can I use a M324p? I ordered a couple of M644p but they are on backorder.

Of course the next thing will be finding the play time....I have lots of old BASIC TRS80 programs that would be fun to get going on an AVR. The only used 128 by 64 resolution IIRC.

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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the code of the mega644 version is about 40K (plus 24K for the 8 BASIC programs). You can only use the mega32 version but I think that some modificatons and re-assembling are mandatory. The mega644 version also needs 4KiB RAM.

regards,
Joerg