Search found 367 matches

by RetroTechie
Wed Nov 02, 2011 12:20 am
Forum: Software
Topic: If it wasn't Life what was it?
Replies: 7
Views: 2346

Re: If it wasn't Life what was it?

by RetroTechie
Tue Nov 01, 2011 6:39 pm
Forum: Emulators
Topic: My new emulator
Replies: 43
Views: 15641

Re: My new emulator

Let me give an example: a binary ripple counter. It consists of a number of bits (flip-flops) representing a binary number. On a clock transition (for example high -> low) the lowest-numbered bit toggles once (1 -> 0 -> 1 -> 0 -> 1 etc). That bit is used as clock input to the next bit, so that next ...
by RetroTechie
Tue Nov 01, 2011 4:12 pm
Forum: Emulators
Topic: My new emulator
Replies: 43
Views: 15641

Re: My new emulator

I'm considering whether it is sufficiently accurate for all communications to propagate only with the clock line, which would instantly reduce me to a fixed 6.5m messages/second and suggest simpler runtime processing. Basically a machine like the ZX81 is a state machine. It has a certain state, and...
by RetroTechie
Tue Nov 01, 2011 3:44 pm
Forum: Sinclair Misc
Topic: Introducing myself (RetroTechie)
Replies: 7
Views: 2482

Re: Introducing myself (RetroTechie)

For MSX, individual parts are much more complex than in ZX81 / Spectrum systems, but overall system setup is much more straightforward / easy to understand (slot mechanism & memory mappers being the exception). For example video: it's a TMS9918 compatible (or V9938 for MSX2) stuck onto I/O ports 98/...
by RetroTechie
Tue Nov 01, 2011 5:43 am
Forum: Sinclair Misc
Topic: Introducing myself (RetroTechie)
Replies: 7
Views: 2482

Re: Introducing myself (RetroTechie)

As ZX81 user/lover, don't even know what an MSX is? :shock: please GO HERE! NOW! The 13 MHz Xtal I'm using is just the clock source, I divide by 2, this gives the 6.5 MHz clock that is input to the ULA (replacing the 6.5 MHz ceramic resonator). Reasons being: I've got 10 pcs of those 13 MHz Xtals (r...
by RetroTechie
Tue Nov 01, 2011 3:12 am
Forum: Hardware
Topic: Rather basic bus question
Replies: 15
Views: 3831

Re: Rather basic bus question

So when designing a circuit I need to ensure that: each line has only one outputting device physically attached; that it has only one logically attached either because some can float when appropriate; that I've found a route to wired-or; or as in the ZX80 (and, off topic, presumably the Spectrum?) ...
by RetroTechie
Tue Nov 01, 2011 2:27 am
Forum: Sinclair Misc
Topic: Introducing myself (RetroTechie)
Replies: 7
Views: 2482

Introducing myself (RetroTechie)

Hello all, Registered today @ this forum since I've been following posts here for a little while, and thought it was time to change from passive to active participation... :) My general background is best described in this post on MSX.org forum: http://www.msx.org/forumtopic9106.html And for some ti...