Denial

Thank you, At some point would like to update the Talkback design and roll in your adapter for a cleaner interface.
Yogi

srowe wrote:Sorry I've not replied, been busy building my FE3 card.

I'm aware of the frequency shift but I've not really experimented with it. I'll try it out shortly.

No worries If you get a chance, would like to see the schema also.
Yogi

Cool. Nice job sorting out the design shortcuts. I've looked at the Maplin reprint awhile ago and the original design does seem kind of 'wonky' to save a few chips. One thing that I found interesting was the V to F clock circuit. Very unique. Would like to hear your impressions of this feature, how ...

what's happening on DATA BUS when CPU try to write on RAM with RAM's R/W line forced High ? CPU is putting data on it, the selected RAM is putting other data on it...... It's a problem! (isn't it?) It depends on how you are using /OE, /WE and /CS. If you are using these input separately then you wo...

Thanks for the reply, yes I had read that thread. My interest is mainly for more musical use of the Speakjet rather then TTS which the R Pi excels at.
Yogi

So I've been think about speech synth lately and an idea hit me. As some may be aware, there is a SpeakJet based product the AtariVox+ that is operated from the A2600's game port. As far as I can see, it's bit-banged from a game port pin at 9600 baud. The programmer's guide details the interface but...

Hi, don't want to state the obvious, but didn't see anyone mention it. Your LED has multi-inputs, are you sure you have selected the correct input that you are plugged into? Even if you plug into the composite connector, most tvs have to be switched to that input in a menu. I have an old toshiba wit...

@Yogi The excess heat does come from the regulator. Changing it to a switching will certainly reduce the heat but make sure you get a good quality regulator as cheap ones can cause a serious amount of ripple on the 5V line and potentially damage irreplaceable vintage custom chips. All very good adv...

Thanks so much, your timing diagram is great! Just what I needed.

yogi wrote:I think I got off track by trying to compare the VIC to an Atari, WRONG

Blasphemy!

Forgive me
Yogi

The CPU is never halted. The beauty with he 6502 is that It only needs to work on one of the phases ( phi2 is high ) of the clock. Sure it starts to set up the address and r/w in the first phase but it doesn't need to. The time is enough when the clock is high and data is read or written on falling...

Thanks very much! Still want to work a VIC-20 into the music! Hope Schema mass produces his MIDI interface someday. Yes, ditto on the MIDI card :) I've been digging into the project's github and going thru the original Maplin design (I found a 6850 in my junk box) I've started experimenting with a ...

Oh, this is a bit confusing to me. I guess I had misunderstood the need for the 65245 xceivers, I thought they provided bus isolation when the 6502 was in RDY state to accommodate the VIC-1. RDY is pulled up and unused in the VIC-20 and irrelevant to this discussion. OK, now another question: how d...

It is two different things. The data buss has to tristste on all 65xx internally regardless. VIC 20 also have buffers for isolating VIC chip and 6502. Both data AND address. The 6510 has an additional tristate capability for the address bus also, thus eliminating these external buffers. Thanks TLov...

One thing I've noticed with this VIC, there seems like alot excess heat from the heat sink. I've only been playing with it for about a month so don't know if this is the norm. But it got me thinking about replacing the original regulator with a switching mode one. Yogi I'd like to know if you are s...

Oh --- yeah that's right. Now that you mention it, it's all coming back. So I guess that since the 2-prong VICs have most of the failure prone parts inside the computer, it doesn't really benefit to buy a high-quality third party power supply. Thats my take on it. OTOH if you have C64s and/or other...