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Rasberry Pi as XEP80?

xep80 80 column

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#51 fujidude OFFLINE  

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Posted Fri Mar 25, 2016 9:43 AM

I  liked easy and well Apple made it to add 80 columns to an Apple 2.  Of course, the Apple 2 had expansion slots.


Edited by fujidude, Fri Mar 25, 2016 9:43 AM.


#52 Fox-1 / mnx OFFLINE  

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Posted Fri Mar 25, 2016 11:17 AM

Maybe Atari could have had a PBI adapter with a PIA to use with the XEP80? Then it would have been faster on the PBI/ECI machines but still useable in the others. (After they fixed the bin-standard video...)
 

Speed-wise, there's no difference between using PBI or Cartslot for this purpose.  In both cases the external PIA communicates with the 6502 using the exact same 8 data lines.

 

The PBI has more potential features but as long as talking about connecting an XEP to a faster PIA, PBI has no additional value.  Being able to use the XEP will still be a matter of loading a driver.

 

When using PBI one has more options to expand features, like adding the driver on external ROM, but when going this way it's probably better, and more cost effective, to ditch the XEP all together and implement the NS-455 / 8048 / RAM in a real PBI device design.



#53 Kyle22 ONLINE  

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Posted Sun Mar 27, 2016 4:41 PM

. . .

When using PBI one has more options to expand features, like adding the driver on external ROM, but when going this way it's probably better, and more cost effective, to ditch the XEP all together and implement the NS-455 / 8048 / RAM in a real PBI device design.

And build it in 800 card form factor like the Bit3, but with an added PBI header.  XL users could put it in a small case, and 800 Incognito users could plug it in the rear slot (and connect via PBI, if necessary).

 

Edit: Even better, put it in the slot right behind Incognito, using a very short PBI cable. Make sure it has a passthrough PBI on the other side of the board for other PBI devices.  It would only need power from the card slot, and it could have a socket for external power when used on XL/XEs.


Edited by Kyle22, Sun Mar 27, 2016 4:45 PM.


#54 scottinNH OFFLINE  

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Posted Sun Mar 27, 2016 6:14 PM

Got this thought experiment that might work? Maybe. What if you used a RasPi in the place of a XEP80?

First, hook the RasPI to the Atari from the joyst port to the USB. of course that would require some sort of parallel to USB interface which is beyond me. But say IF it could be done...

Second, the RasPi could be programmed to send the info through it's HDMI to a current LCD TV with glorious simulated 80 column text.

might be able to use the XEP80 drivers.

of course the first part with the interface is (insert magic here).

I'm not a hardware guy but the software sounds doable.

Any thoughts?

 

Just to add:

The Pi runs a Linux OS, with lots of "OS stuff" going on.... which won't take kindly to being powered on and off (ie, not doing a proper OS shutdown on the Pi).  It could work, but it wouldn't be robust and the OS install will occasionally get corrupted (the way an OS does, if you power off unexpectedly.

 

A better choice to avoid a peripheral having an OS.

 

Here's one option:

http://www.hobbytron...o.uk/serial-vga

 

Another option is an Arduino with a VGA/HDMI shield. There's tons. Work out the XEP80 protocol, write some firmware that answers it and outputs the display. 

 

You can also do VGA output on a modified (25-28MHz) Arduino. I've seen so many articles on this lately, I forget which came first. But here's one:

http://dqydj.net/how...rom-an-arduino/

 

I could spend a year trying to do something like this, and still be learning. I just dabble with the Arduino. But one notion I got from all of these articles: if you try to do something as intensive as "Arduino video out" on the Arduino itself: don't try to do many other things at the same time. Timings and interrupts and all that. You'd perhaps use one Arduino to hold most of the firmware and behavior (fonts, text flow etc), and a second Arduino basically given a lifetime job of listening to the serial lines for instructions to draw VGA.

 

It's great to see folks looking at the newer electronics hardware, and how to pair it with Atari.



#55 fujidude OFFLINE  

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Posted Mon Mar 28, 2016 6:51 PM

 

The Pi runs a Linux OS, with lots of "OS stuff" going on.... which won't take kindly to being powered on and off (ie, not doing a proper OS shutdown on the Pi).  It could work, but it wouldn't be robust and the OS install will occasionally get corrupted (the way an OS does, if you power off unexpectedly.

 

A better choice to avoid a peripheral having an OS.

 

Or don't sweat it it so much.  Just make a backup image of the SD card once in a while.  Easy to do.  In the not too terribly common occurrence of corruption, just dump the image back onto it.  Bam.



#56 ricortes OFFLINE  

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Posted Tue Mar 29, 2016 10:39 AM

Just a little how to that Michael taught us with his genlock. The Atari can vary the clock a little bit w/o losing sync or otherwise going nuts. What could be done is pick off the sync signals of the RPi composite video and use a phase locked loop circuit to get the timing exactly right. IIRC he used a 74ls47 chip as the PLL. Now no matter how you hook up the RPi, serial or parallel, the video is synced. In use, you could send the RPi a command to display a jpeg or load a browser to use the WWW. Everything necessary to make the Atari compatible with current technology from USB to thumb drives <SIO2PC>. ethernet. et al could be hung on the RPi. Things that make development slow on the Atari would be faster since the I/O is occurring on the RPi. You could even run an emulator on the RPi.

 

I'm not up to date on the RPi. Did they ever fix the USB crashing the system ~daily? 



#57 rockdoc2010 OFFLINE  

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Posted Wed May 4, 2016 3:15 AM

Back in 1843 I installed an OS mod that gave my 800XL 80 columns

Are you trying something else?

 

Douglas



#58 rockdoc2010 OFFLINE  

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Posted Wed May 4, 2016 3:16 AM

yes it was steam driven...



#59 rockdoc2010 OFFLINE  

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Posted Wed May 4, 2016 3:22 AM

i would like to program a Tiny for background rgb leds.. imagine a keyboard doing the FUJI colour scheme.. or based on the music/sounds

 

Bueler Beuler Beuler?



#60 rockdoc2010 OFFLINE  

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Posted Wed May 4, 2016 3:29 AM

 

Yes, its really all about where the PI thinks it's getting key strokes from. I don't know about straight into VI or Pico, for two reasons:

1. There will need to be some kind of SIO response from the PI for it to participate as a SIO device. Of course, you could go straight serial through an R: driver, but then you'd need the linux serial TTY set up, which isn't hard to do.

2. Vi or Pico will be expecting a certain key mapping and set of commands. Somebody in between would need to map the atari keys and the atari program output ( such as print a character at position x,y ) to commands that would effect the same result on the screen.

 

 

Not a fan of melding linix and Atari it just seems wrong.

But Arduino can do just as much. The Raspberry is its own computer. The arduino is a better choice to convert and preserve the Atari.

 

Douglas



#61 danwinslow OFFLINE  

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Posted Wed May 4, 2016 6:26 AM

 

 

Not a fan of melding linix and Atari it just seems wrong.

But Arduino can do just as much. The Raspberry is its own computer. The arduino is a better choice to convert and preserve the Atari.

 

Douglas

 

Well, I don't care what kind of little SBC is used, I was just talking about PI because that was the context. I have no idea what you mean about 'convert and preserve' or why you would think that 'linix' and the Atari are morally incompatible.

;)


Edited by danwinslow, Wed May 4, 2016 6:27 AM.






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