AVR

[Tomas Kouba]

> taktovacej frekvencii 20MHz iba 200ns, pretoze jedna instrukcia
> potrebuje 4 hodinove takty. ATMEL rada naproti tomu potrbuje 12, u

Takto vyrobil puvodni procesor 8051 Intel a Atmel to z duvodu 
kompatibility dodrzuje. Existuje vsak i klony, ktere to nedodrzuji 
(Dallas deli 4).

> vacsiny instrukcii vsak 24 hodinovych taktov. Kedze MICROCHIP sa
> prisne
> drzia filozofie RISC procesorov, obvzlast ich aritmeticka
> instrukcna

Atmel sam oznacuje AVR jako RISC, cituji z 
http://www.atmel.com/atmel/products/prod23.htm

Atmel's new AVR microcontrollers have a RISC core running single 
cycle instructions(instruction cycle 62 ns@16 MHz) and a well defined 
I/O structure that limits the need for external components. Internal 
oscillators , timers, UART, SPI, pull-up resistors, pulse width 
modulation, ADC, analog comparator, and watch dog timer are some of 
the features you will find in AVR devices.

AT90S1200 ma 80 instrukci, vetsinou jednocyklovych - viz. 
http://www.atmel.com/atmel/acrobat/doc0856.pdf

Tomas

--
                   Ing. Tomas Kouba
Institute of Physics, AS CR    ph.: +420-2-24311137
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Czech republic                 URL: http://www.fzu.cz/~kouba