Re: A new pseudo-disk for Apple 2.

"Linards Ticmanis" <ticmanis@xxxxxx> wrote in message
news:44c15b95$0$22008$9b4e6d93@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Problem with this: On a II/II+ you can't reliably freeze the CPU for
more than about 5 cycles, else it'll lose state.

Sure you can. Softcard does. The trick is that the clock is only removed for
a few microseconds but then
is allowed for one cycle while READY is not asserted. So you can do DMA for
say 80% of all the cycles
and allow the 6502 to fetch a byte now and again.

The problem is that any such solution will increase the complexity of the
board very significantly.

-Alex.


.

Relevant Pages

  • Re: Blast from the past... Z80!
    ... ld a,; two microseconds ... Okay, so effective addressing calculations went snail slow on the 8086 ... supposed to take 12 clock cycles, and I don't even remember if those ...
    (sci.electronics.design)
  • Re: A new pseudo-disk for Apple 2.
    ... more than about 5 cycles, ... The trick is that the clock is only removed for ... any reason for choosing the MultiMedia Card over the more common ...
    (comp.sys.apple2)
  • Re: replacement parts
    ... >>Since these series caps are essentially connected between mains supply ... >>half cycles and 12V on positive half cycles) you should not use any ... those caps seem to be doing the trick. ... I've got 2 monitors ...
    (sci.electronics.repair)
  • Re: Accurate(ish) frequency measurement
    ... The simple method - counting cycles - would sort of work. ... clock to measure things more accurately isn't too feasable. ... an interpolator will find Delta_T1 = the time from the active ... edge of the gate to the next active edge of the unknown clock. ...
    (sci.electronics.design)
  • Re: Division by Zero in Nature, and Decomposition of Time.
    ... It *starts* with cycles, historically, but is not ... "the whole universe" to build a clock, ... > they would be either zero or very near zero relative to everything ... > that they simply do not exist relative to an observer such as us. ...
    (sci.math)