18 Jan
2014
18 Jan
'14
8:01 p.m.
On Jan 18, 2014, at 2:38 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
In college, we had a PDP-11/20 with DACs and an RC11 disk. So I did an X/Y display that
uses the disk as refresh memory. This uses the ?inhibit address increment? feature in the
older disk drive DMA controllers, so you can set up a DMA for the whole refresh buffer,
with all words transferred to the same address, i.e., the DAC data buffer address.
paul
...
haven't really done anything with the one I have. Could you do
something interesting such as driving an X-Y scope with the D/A
channels?
Yes. The only problem woudl be that the DACs are driven by software,
unless you keep writing valuse ot them the outputs will not change. So to
get a pattern on the XY display you'd have ot keep on writing vlaues ot
hte DACs. Of course if you have a storage display you could just write
once nad let the display store the image.