On Wed, Dec 05, 2018 at 01:23:00PM +0100, Mia Magnusson wrote: > Den Thu, 29 Nov 2018 18:17:57 -0600 skrev Segher Boessenkool > <email@example.com>: > > On Fri, Nov 30, 2018 at 12:48:17AM +0100, firstname.lastname@example.org wrote: > > > I've got a question I can't answer out of my head and can't > > > currently set any test bench for - how does the 6502 and 6510 > > > behave when it comes to getting off the bus. I know we can make > > > 6510 off the address bus with the additional line that is not > > > available in 6502 but the question is: does any of the two > > > (especially 6510, which surely has the ability) get off the bus by > > > itself like during other phase of the clock cycle? > > > > The 6502 always drives all address pins. The 6510 whenever AEC is > > high. > > Afaik the 6502 also drives the data bus and other signals even in it's > "inactive" halv cycle. Otherwise the VIC 20 wouldn't had to split the > data bus in a "CPU" and "VIC" part. As far as the 6502 (and 6510!) is concerned, there *is* no "inactive half cycle", so yes. (That is all VIC-II stuff, and 6502 doesn't have AEC anyway.) Both 6502 and 6510 drive everything for full cycles (but keep in mind setup time, etc.) SegherReceived on 2018-12-05 17:00:08
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