Latching the bank address the right way

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tokafondo
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Joined: 11 Apr 2020

Re: Latching the bank address the right way

Post by tokafondo »

BigDumbDinosaur wrote:
tokafondo wrote:
I've kept reading about this and wondered about using a flip-flop instead of a latch. Would be of any benefit the fact that a flip-flop acts on edges and is clocked?

The latch used to generate the bank bits is a transparent latch, meaning when the latch is opened, its outputs follow its inputs. A flop doesn't have that characteristic.
I've always understood (wrongly, it seems) that for the latch system to work, two clock cycles were needed: first for latching A16-A23 and then another one to get D0-D7.
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Dr Jefyll
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Re: Latching the bank address the right way

Post by Dr Jefyll »

tokafondo wrote:
I've always understood [...] two clock cycles were needed
No. But I suppose you could say two half-cycles are needed. The Phi2-low period is for transferring A16-A23, and the Phi2-high period is for the transfer of D0-D7. Total: one clock cycle.

-- Jeff
In 1988 my 65C02 got six new registers and 44 new full-speed instructions!
https://laughtonelectronics.com/Arcana/ ... mmary.html
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