Recreating the RSVE mod…

[exxos]

Doesn't the RSVE remap speeds like 100bps to 38400 etc ? And the simple mode just basically doubles the clock so you have to use a slightly slower speed for the now double speeder clock ?

[sporniket]

That's what I understand to.

[Darklord]

I believe the 3 lower baud speeds are auto-remapped.

From the manual:

"With the RSVE hardware, the Baud-rates 115200/57600/38400 occupy the positions of 150/134/110 in any
case, so there is no point in reassigning them there. The reassignments are transparent for programs"

So when you use SETTER.TTP to "adjust" MFP.PRG, it has 6 places, marked by a "u" if no RSVE or such on board.

Otherwise, it's old speed, then new speed. So in the case of my BBS, I'd mark it:

19200
38400
u
u
u
u

Because the BBS Express! ST software requires 19200 for lowest speed, connect speed, and maximum speed,
to work correctly at faster rates. So HSModem "fools" it into using the new/doubled rate.

I reckon anyway... :)

Thanks.

[sporniket]

Preparing the conversion to kicad...

2022-11-06--rsve-draft-schematic.jpg

Thinking about the addition of a switch, it may not be as trivial as I thought : I believe that make the clocks signals transits through flying leads all over the motherboard to be selected by the switch and going back to the circuit is not a good idea (emits noise all over the motherboard). I am now thinking about using a selector (either a '257, or using discrete components) that would be commanded by said switch. Any thought about that ?

[Darklord]

If you think the switch is a bad idea, leave it out.

It's only there (according to the literature I've read) for
things like FAX software 'n such that breaks at the higher
speeds.

Personally, I'll not be doing any fax'ing with my machines. :)

The RSVE design from H.A. (HSModem author) did *not*
have a switch.

The version from the ST Format article is the only I've seen
that has.

Thanks.

[sporniket]

Then I will stick to the original design of the RSVE to make the schematic.

EDIT : my work will happen there

[Darklord]

Thank you so much for attempting this - really appreciated! :)

[frank.lukas]

To use higher baud rates you need an accelerated Atari ST ...

[Darklord]

To use higher baud rates you need an accelerated Atari ST ...

Right, the higher ones like 57.6 and up...but a stock 8mhz machine
can do 38.4 just fine (assuming you have some sort of RSVE device
installed, that is).

Thanks.

[sporniket]

After imagining being a little bit creative with the layout, I finally decided to also stick to the original...

Capture d’écran du 2022-11-09 05-34-14.png

...but since I am not limited to a single layer for the traces, I will put all the component on the top.

Capture d’écran du 2022-11-09 05-37-52.jpg

Now it's time to route and setup the pcb. Since it will be a quite noisy circuit, I would go with a 4 layers pcb. As it is small (36x44mm), the cost will stay low.