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Discussion Groups | AVRclub | Re: [AVR club] avr with huge external memory

Atmel AVR Microcontroller discussion group.

avr with huge external memory - Frank - Apr 29 10:30:00 2003

I need help. This can sound crazy, but we are trying to use avr
microcontrollers with huge external data and programming memories.
We have a application to a device with 256kB of programming memory
and a data bank with at least 256Kb. As we are using avrs for others
devices, we would like to use then in that case too. But we can not
find any reference desing or even a glue about that . So I am here
asking for your help. Any help will be very wellcome. I do apologize
for my terrible English and Thanks in advance.

Frank Alcantara



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Re: avr with huge external memory - emersonsantosrj - Apr 29 21:32:00 2003

Vc ja tentou usar umas das portas de IO como decodificador de
memoria e de ES ??? e basta usar outra porta como Entrada/Saida de
dados ... para a memoria ou perifericos

A ideia eh simular um microprocessador comum :) com as Portas de I/O



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Re: [AVR club] avr with huge external memory - Max - Apr 29 22:29:00 2003

I have done this very same adding 512K to an Atmel ATMega128. Since the 128 has support for external RAM (64Kb), all I did was add a VHDL falling edge triggered 3 bit counter (to control ADDR[16..18] ) inside a CPLD (Altera). If this interests you, I can provide more extensive details. You could easily accomplish the same task using 74HCxx semiconductors.

Since this counter controls the upper address bits only, it could easily be expanded to control gobs of extra memory, i.e. > 512K!!

If I can be of more help, let me know.

Thanks,

Max

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----- Original Message -----
From: Frank
To: avrclub@avrc...
Sent: Tuesday, April 29, 2003 10:30 AM
Subject: [AVR club] avr with huge external memory I need help. This can sound crazy, but we are trying to use avr
microcontrollers with huge external data and programming memories.
We have a application to a device with 256kB of programming memory
and a data bank with at least 256Kb. As we are using avrs for others
devices, we would like to use then in that case too. But we can not
find any reference desing or even a glue about that . So I am here
asking for your help. Any help will be very wellcome. I do apologize
for my terrible English and Thanks in advance.

Frank Alcantara Yahoo! Groups Sponsor
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RES: [AVR club] Re: avr with huge external memory - Frank Alcantara - May 1 16:55:00 2003

Oi Emerson

Obrigado pela atenção e sugestão. Na verdade sim já pensei nisso, mas
creio que esse assunto mereça um pouco mais de estudo da minha parte.
Essa informação sobre os jumps ficarem limitados a Flash deve ser
testada e considerada como um grave limitador. Novamente obrigado. Hi Emerson
Thanks for your attention and suggestion. In real, Yes I tried this
before. But I believe this topic must have a little more attention from
me. The information about all jumps are limited to flash internal area
must be checked and if there is no way to bypass this limitation, we
will use another family to this design. Again thank you very much.
Best regards,

Frank Alcantara.
Thyamad Consultoria.
frank@fran...
http://www.thyamad.com <http://www.thyamad.com/>

-----Mensagem original-----
De: emersonsantosrj [mailto:emersonsantosrj@emer...]
Enviada em: terça-feira, 29 de abril de 2003 22:32
Para: avrclub@avrc...
Assunto: [AVR club] Re: avr with huge external memory

Vc ja tentou usar umas das portas de IO como decodificador de
memoria e de ES ??? e basta usar outra porta como Entrada/Saida de
dados ... para a memoria ou perifericos

A ideia eh simular um microprocessador comum :) com as Portas de I/O Yahoo! Groups Sponsor <http://rd.yahoo.com/M=229633.3212141.4526654.2595810/D=egroupweb/S=1706
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