Re: Switchless ROMs

From: bwack <>
Date: Tue, 27 Dec 2016 06:03:21 -0800 (PST)
Message-ID: <>
Interesting approach. Regarding the detection of $fffe on the address bus, I
suppose a MCU can do that. Forget interrupt service routines in the MCU and
just poll the GPIO in a loop for $fffe and perhaps chipselect also, break
the loop then watch for bit 8 or 9 at a specific time after that and set the
bank on the larger EPROM. Perhaps an atmega at 32MHz will do it ? or perhaps
an stm32 or other of choice, but they must be 5v tolerant.

Ok i changed my mind. Link the kernals to the firmware of an stm32f0. Have
it replace the eprom also. The stm is cheap and 5V tolerant. 

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