Re: cbm 8032 motherboard + 4164

From: Segher Boessenkool <segher_at_kernel.crashing.org>
Date: Thu, 13 Oct 2016 15:55:58 -0500
Message-ID: <20161013205556.GC32191@gate.crashing.org>
On Thu, Oct 13, 2016 at 10:11:59PM +0200, Gerrit Heitsch wrote:
> >>Doing 5 refresh cycles per scanline will take 51 scanlines to read all
> >>256 addresses.
> >
> >This is about 3ms btw, so 2ms DRAMs shouldn't work well at all.
> 
> Small error here... DRAM with 128 cycle refresh needs that in 2ms. All 
> DRAM with 256 cycle refresh I know of needs that in 4ms so we're good 
> either way with the 5cycle/scanline implementation.

Ah right, 128/2ms and 256/4ms are the two main timings from this era.
Thanks for the correction.


Segher

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Received on 2016-10-13 21:00:41

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