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ATMEL GETS HUGE

by Tom Cantrell

Start ý Feeling Pretty SLIC ý Memory MIPS ý Making a Connection ý Co(de)signer ý Huge Idea ý Sources and PDF

MAKING A CONNECTION

As important as the individual features of the MCU and FPGA, is the way the two are connected. Based on the limited information at hand, it appears Atmel has adopted a simple approach that treats the FPGA much like another onboard 8-bit peripheral. Thereýs an address decoder for generating up to 16 pseudochip selects into the FPGA and, going the other way, 16 interrupt lines that are fed from the FPGA into the MCU.

A loosely coupled scheme makes sense in the context of Atmelýs cut-and-paste approach to building chips. Besides putting together an MCU and FPGA, they also offer FPGA with gate array, and I expect theyýll offer more combinations. Keeping the interconnect between modules simply facilitates reuse by minimizing the tweaks necessary to glue together the pieces.

In the case of the AT94K, some accommodation is made to support synchronism between the MCU and the FPGA. The MCU has access to the FPGAýs eight global clocks and can drive two of them relying on its own combination of internal and external oscillators, clock dividers, timer/counters, and so on.

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