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1
Amstrad CPC hardware / Re: GX4000 console reset button
« Last post by rewk on Yesterday at 21:13 »
On my development GX, I do that by shorting the the common node of R17, R90 and D10 to GND.

Nice ! That's where I will put my reset button then. Since my model is a French one, it has a nice empty hole at the back, ready to be used that way. :)

There is no direct way of getting the reset

It may have been possible to cut the track providing 5v to the cartridge and add a mosfet tied somewhere that get low on reset to power it. What an ugly hack...  :o


I can update your card if you want, but for that you have to ship it back to me


Definitely ! I guess there is no easier way to reprogram the PLD ?


EDIT: It looks I'm lucky, my C4CPC resets correctly ! Yay!

2
Amstrad CPC hardware / Re: GX4000 console reset button
« Last post by gerald on Yesterday at 20:48 »
oh hell yes please. Can you update Both of them! I have 2 you see.
No problem. PM  ;)
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Amstrad CPC hardware / Re: GX4000 console reset button
« Last post by CraigsBar on Yesterday at 20:33 »
Early C4CPC  (90% of the 1st batch) does not see the reset.
There is no direct way of getting the reset. On the later version, I've implemented a system in the PLD that detect it indirectly through the ACID signals.
But this does not reset the microcontroller either, just inform it that the CPC has reset.

By default, the CPC just ignore it so when you use the system cartridge it will reboot immediately. Only CprSelect takes advantage of it and is reloaded on a reset.

I can update your card if you want, but for that you have to ship it back to me  ;D
oh hell yes please. Can you update Both of them! I have 2 you see.
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Amstrad CPC hardware / Re: GX4000 console reset button
« Last post by gerald on Yesterday at 20:17 »

The button goes between BSRT on the ASIC and Ground not +5v this is the exact same connection as is used on the BusReset on the expansion port of the 464+ and 6128+ and it behaves in the same way. so no it unfortunately does not reset the C4CPC, that still needs a power cycle.
Early C4CPC  (90% of the 1st batch) does not see the reset.
There is no direct way of getting the reset. On the later version, I've implemented a system in the PLD that detect it indirectly through the ACID signals.
But this does not reset the microcontroller either, just inform it that the CPC has reset.

By default, the CPC just ignore it so when you use the system cartridge it will reboot immediately. Only CprSelect takes advantage of it and is reloaded on a reset.

I can update your card if you want, but for that you have to ship it back to me  ;D


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Programming / Re: Expanding Elite
« Last post by Fessor on Yesterday at 20:11 »
I was able to successfully narrow down the drawing routine for the circles, even if I don't quite understand the mechanics behind it. I have no idea whether you can put a mask on the outer boundary or I just haven't found it yet. The code modifies itself to set a mask, but that only affects the rough inside of the circle. I might guess that these bytes are simply drawn from a table depending on the radius.

The spectrum also has filled circles, e.g. used for the sun. They probably had to make compromises because of the color clashing and made the decision to leave it to simple circles. Filled planets and xored vector graphics probably didn't look that good.
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Amstrad CPC hardware / Re: GX4000 console reset button
« Last post by gerald on Yesterday at 20:08 »
On the GX4000, there is no such resistor and the BRST is directly connected to 5V. Which means that bringing it to low would short.


Or am i missing something ?
You're not missing anything  ;D
The proper way to do a reset on a GX4000 is to discharge the capacitor of the internal reset RC circuit that drives /SRST.
On my development GX, I do that by shorting the the common node of R17, R90 and D10 to GND.
It could also be done directly at C26 / Asic pin 156, but is a bit more stress for the capacitor as you are doing a real short.


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Programming / Re: Expanding Elite
« Last post by Sykobee (Briggsy) on Yesterday at 18:48 »
It sounds like there's a lot of room for improvement when it comes to the graphics rendering pipeline.
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One (dumb? unrealistic?) idea, what about creating a new language? Since you know the primary target (Z80), what about a language that would abstract most of it while allowing some syntax that wouldn't completely hide the low level? You could borrow ideas of any other language you like and incorporate them in your new language, without having to care about compatibility or any undesired inheritance.
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I knew that question would come up. ;)    I think it's possible but it's not that easy because of the way the keys are used.
If, by chance, you have a little time to waste trying, that would be really great because accelerating with the up button on joypad is not good for the thumb!  :P
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Amstrad CPC hardware / Re: LambdaSpeak FS
« Last post by genesis8 on Yesterday at 16:55 »

However, to add YMODEM is no deal and no problem.  :)  Which one (exactly) do you want? I will add it for file transfer if you like.


Ymodem CRC 1k as seen in http://pauillac.inria.fr/~doligez/zmodem/ymodem.txt
Ymodem-g seems a bit too much for the CPC ?
Zmodem would be a dream of course
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