Den Wed, 21 Feb 2018 10:52:24 +0100 skrev didier derny <didier@aida.org>: > for the 6509 I guess it's not so simple... the data has to be > inserted at the right time and aec is missing on the 6502 Fortunitely, according to all the schematics I've looked at (P500, low profile and high profile B's, at Zimmers mirror of the defunct funet.fi site) the AEC is not used but tied to VCC using a resistor. I don't know of any other 6509 based computers, so maybe the AEC were never used. The coprocessor slot of the B series uses separate muxes. 4-to-1 muxes is used for the DRAM adress buss whith one input for the refresh counter, two inputs for row/column in 6509 mode, and the fourth input comes from the coprocessor connector. It's a bit strange that the coprossesor only can access dram directly while everything in page 15 (I/O e.t.c.) is always connected to the 6509 and a hack using two 6526's connected to each CPU is used to communicate betweeen the 6509 and 8088. That could probably had been made nicer, but somehow it works. It's interesting that the B refresh circuits is used also in 8088 mode even though the ras/cas muxing is done separately on the 8088 board in 8088 mode. > for the 6525 I was thinking to use a GODIL, > http://www.oho-elektronik.de/index.php?c=1&s=index > > I tried to replace a 6530 a few years ago, but the GODIL I was using > was broken > > I was testing on a kim but I had to give back the kim board before > the working godil arrived > > the main problem with the GODIL: it is huge !!! and with all these > pins a lot of risks for a short circuit > > > there is also a product made by enterpoint, the craignel > https://www.enterpoint.co.uk/shop/home/48-craignell1.html > > it's really expensive... and the options for he vcc/gnd pins are > really limited Back in the days there were a version of the Intel 8048 series that acts like a peripherial. But I think it has too few pins and also it uses Intel instead of 6800/6502 bus handshake. Anyways it seems unnecessary to emulate all of an 6525 as the two first ports seems similar to the common 6821 or maybe the rather common 6522. > the cbm II is really new for me, I only saw them once at the Cebit > 1982 About the same here, might have seen one at some fair back in 1983, but have been reading about them now and then in recent years. But they are so rare and seem so expensive that a replica might seem like a good hardware project. :) I know that I'm the kind of person who overthinks things and feature creeps everything until it's not feasable, but I think some kind of "universal-ish Commodore 8-bit board" would be nice. Here in Sweden a guy who produce small add-ons for vintage computers (for profit) is doing a thing that can emulate CBM keyboards. Something similar would probably be necessary as PET, CBM-II/B, VIC20/C64 uses different electrical keyboard layouts. > I have a new world to discover :) +1 -- (\_/) Copy the bunny to your mails to help (O.o) him achieve world domination. (> <) Come join the dark side. /_|_\ We have cookies. Message was sent through the cbm-hackers mailing listReceived on 2018-02-21 16:00:03
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