F18A MK2

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F18A MK2

Daniel O'Shea
...exciting stuff happening over here:

http://codehackcreate.com/archives/592

Customisable FPGA with digital video out and 512KiB SRAM on-board, in a
600-mil 40-pin DIP sized package!

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Re: F18A MK2

earth1dome1

Real bummer... This is written for Adam and Coco computer system. Might try suggesting it somewhere else. This is a C= forum. Jeremy aka weirdwolf.
On Thursday, July 12, 2018, 11:01:54 PM PDT, Daniel O'Shea <[hidden email]> wrote:


...exciting stuff happening over here:


Customisable FPGA with digital video out and 512KiB SRAM on-board, in a
600-mil 40-pin DIP sized package!

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Re: F18A MK2

Daniel O'Shea
Jeremy wrote:
> Real bummer... This is written for Adam and Coco computer system. Might
> try suggesting it somewhere else. This is a C= forum.

...if only there were some way to reprogram an FPGA and repurpose it for
use with a C= system - such a shame! ;-)


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Re: F18A MK2

Steve Gray
Its a shame the guy doing this project won't get off his butt and finish it:

;-)  ;-)

Steve



From: Daniel O'Shea <[hidden email]>
To: [hidden email]
Sent: Friday, July 13, 2018 7:02 PM
Subject: Re: F18A MK2

Jeremy wrote:

> Real bummer... This is written for Adam and Coco computer system. Might
> try suggesting it somewhere else. This is a C= forum.


...if only there were some way to reprogram an FPGA and repurpose it for
use with a C= system - such a shame! ;-)





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Re: F18A MK2

E CHORNY

Ooh! Possible sprites on the VIC -20!

What's next? Sprites on the PET?

:-)

Ernie


---------- Original Message ----------
From: Steve Gray <[hidden email]>
Date: July 13, 2018 at 10:27 PM

Its a shame the guy doing this project won't get off his butt and finish it:

;-)  ;-)

Steve



From: Daniel O'Shea <[hidden email]>
To: [hidden email]
Sent: Friday, July 13, 2018 7:02 PM
Subject: Re: F18A MK2

Jeremy wrote:

> Real bummer... This is written for Adam and Coco computer system. Might
> try suggesting it somewhere else. This is a C= forum.


...if only there were some way to reprogram an FPGA and repurpose it for
use with a C= system - such a shame! ;-)






 

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Re: F18A MK2

MiaM
Den Sat, 14 Jul 2018 00:26:54 -0400 (EDT) skrev ernie chorny
<[hidden email]>:
> Ooh! Possible sprites on the VIC -20!
>
> What's next? Sprites on the PET?

The "problem" with PET is that it's not obvious where in memory to map
hardware expansions, as different models have free memory at different
places.

--
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Re: F18A MK2

Steve Gray
One of the problems with PET expansion is the IO chips are not decoded properly. Each chips uses one unique address line to enable the chip... all to save one measly '138 decoder.

$E81x - PIA 1
$E82x - PIA 2
$E84x - VIA
$E88x - CRTC

If those lines were decoded properly there would be all kinds of free space: $E83x, $E85x, $E86x, $E87x, $E890-E8FF.
Instead, selecting an address with 2 or more of those lines will enable 2 or more chips at the same time.
Example:  $E83x would select both PIA's at the same time... not good. 

In any case, AFAIK, the $E80x space is free on all pets.

BTW, I have done a little work on the VYMS-20 cart - replacing the RCA video/audio jacks with a 1/8" TRRS  jack and also adding a reset button.
I'm hoping to get more done this summer.

Steve



From: Mia Magnusson <[hidden email]>
To: [hidden email]
Sent: Saturday, July 14, 2018 2:54 PM
Subject: Re: F18A MK2

Den Sat, 14 Jul 2018 00:26:54 -0400 (EDT) skrev ernie chorny

<[hidden email]>:
> Ooh! Possible sprites on the VIC -20!
>
> What's next? Sprites on the PET?


The "problem" with PET is that it's not obvious where in memory to map
hardware expansions, as different models have free memory at different
places.

--
(\_/) Copy the bunny to your mails to help
(O.o) him achieve world domination.
(> <) Come join the dark side.
/_|_\ We have cookies.




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Re: F18A MK2

MiaM
Den Sat, 14 Jul 2018 19:12:12 +0000 (UTC) skrev Steve Gray
<[hidden email]>:
> One of the problems with PET expansion is the IO chips are not
> decoded properly. Each chips uses one unique address line to enable
> the chip... all to save one measly '138 decoder. $E81x - PIA 1$E82x -
> PIA 2$E84x - VIA$E88x - CRTC If those lines were decoded properly
> there would be all kinds of free space: $E83x, $E85x, $E86x, $E87x,
> $E890-E8FF.Instead, selecting an address with 2 or more of those
> lines will enable 2 or more chips at the same time.Example:  $E83x
> would select both PIA's at the same time... not good. In any case,
> AFAIK, the $E80x space is free on all pets.

A way to get around this would be something that sits between the CPU
and it's socket.

Are there any PET motherboards where the CPU isn't socketed?

> BTW, I have done a little work on the VYMS-20 cart - replacing the
> RCA video/audio jacks with a 1/8" TRRS  jack and also adding a reset
> button.I'm hoping to get more done this summer. Steve

Is it possible to get S-video from that chip? If so a C64/C128
compatible 8-pin DIN connector might be a good choice.

1/8" jacks kan be a bit of a mess. Stuff with only mono audio might
have video and audio on the pins that's used for right/left with stereo
audio. If you have stereo audio and an additional signal ground can be
either on the sleeve (older mobile phones from for example SonyEricsson)
or the ring closest to the sleeve (iPhone and more modern mobile
phones from other brands). I think the rationale for Apple to move the
ground might have been to get the microphone signal away from the
headphone output signal. Also SonyEricsson used the same pin (the ring
next to the sleeve) both for composite video output and microphone
input on the same product, Vivaz, a Symbian phone,

--
(\_/) Copy the bunny to your mails to help
(O.o) him achieve world domination.
(> <) Come join the dark side.
/_|_\ We have cookies.