On 7/10/2019 11:51 AM, Gerrit Heitsch wrote: > On 7/10/19 6:01 PM, Francesco Messineo wrote: >>> >>> Interesting... So, you'd read several bytes whose value you actually >>> don't care about... but the decoder hardware would recognize *which* >>> bytes you'd read; and, from that, infer what MMU operation you wanted? >> >> exactly. That's how the bank switching for RAM/ROM banks work on the >> 16K language card of the Apple II for example. > > That's also how the RAM/ROM switching works in TED from the 264 > series. You write to address $FF3E to enable ROM and to $FF3F to > enable RAM. It's only the write cycle to these addresses that matters, > not what you write. > > Gerrit > > > For reference, the 6847 does the same. All of the config of the IC is done that way. -- Jim Brain brain_at_jbrain.com www.jbrain.comReceived on 2020-05-29 22:32:10
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