Amiga.org

Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: gaula92 on March 02, 2010, 09:45:37 PM

Title: Looking for a case for my Altera-DE1 based Amiga
Post by: gaula92 on March 02, 2010, 09:45:37 PM
Hello there!

The Altera DE1 makes a great Minimig-like Amiga, with all the features of the Minimig+Memory Expansion+Arm controller, but... mine lacks a case.
Do you guys know of a proper case for the DE1?? Does it fit any kind of standard case?

I've got Loriano's (TheDaddy's) case for Minimig. I'd like something half that cool for the DE1!

regards
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: koaftder on March 02, 2010, 09:47:09 PM
Quote from: gaula92;545933
Hello there!

The Altera DE1 makes a great Minimig-like Amiga, with all the features of the Minimig+Memory Expansion+Arm controller, but... mine lacks a case.
Do you guys know of a proper case for the DE1?? Does it fit any kind of standard case?

I've got Loriano's (TheDaddy's) case for Minimig. I'd like something half that cool for the DE1!

regards


Nothing beats a home made case. Be creative and post pictures!
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: gaula92 on March 02, 2010, 10:01:43 PM
This poor DE1 had a Snes case as home :D
I made cuts for the connectors with a kitchen knife. It was the ugliest thing I've ever created... nah, I'm not into home-made cases. I'd like something ready to use in this "case" (you get it? heh, my first english joke :D).
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: ChaosLord on March 02, 2010, 10:38:37 PM
How much did your Altera DE-1 cost?
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: Dr_Righteous on March 02, 2010, 10:51:16 PM
They're $150 from Terasic. I have my eye on the DE2-70 myself, just need to find myself a student.

http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English&CategoryNo=13&List=Simple

PS... Would the DE1 fit in a minimig case? 153x153mm is pretty small.
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: bbond007 on March 03, 2010, 12:08:34 AM
Quote from: gaula92;545933
Hello there!

The Altera DE1 makes a great Minimig-like Amiga, with all the features of the Minimig+Memory Expansion+Arm controller, but... mine lacks a case.
Do you guys know of a proper case for the DE1?? Does it fit any kind of standard case?

I've got Loriano's (TheDaddy's) case for Minimig. I'd like something half that cool for the DE1!

regards


Could it run the new AGA core?
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: ChaosLord on March 03, 2010, 12:54:48 AM
@bbond007  The Altera DE1 is limited to 4096 colors like an A500.  So AGA would be sort of useless on it.
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: RedskullDC on March 03, 2010, 08:23:27 AM
Hi ChaosLord et al.
Quote from: ChaosLord;545953
@bbond007  The Altera DE1 is limited to 4096 colors like an A500.  So AGA would be sort of useless on it.


Limited to 4096 colours...

Unless you wire up an alternate VGA interface with a larger resistor network to one of the GPIO connectors. Easy enough to do.

Example:
I use one of these:
http://www.nkcelectronics.com/vga-breakout-board-with-db15-female-connector-and-pin-head15.html
wired up to a Spartan3 board (which only has one bit per colour) to get 4bits per colour.

Cheers,
Red
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: ChaosLord on March 03, 2010, 10:06:00 AM
@RedSkullDC
Your link says:
Quote
 It allows the wiring of 12-bit VGA signal + HSYNC + VSYNC.
12-bit = 4096 colors

AGA requires 16777216 colors
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: RedskullDC on March 03, 2010, 12:44:06 PM
Hi ChaosLord,

Quote from: ChaosLord;545984
@RedSkullDC
Your link says:
12-bit = 4096 colors

AGA requires 16777216 colors


Was just an *example* to show that FPGA boards can easily be expanded for more bits per colour.

You've no doubt noticed on the page for the adapter that it has 5 jumpers (SJ1-SJ5) to allow it to act as a simple 16pin header to DB-15 breakout.
One would need an intermediate board, with a suitable resistor network, between a DE1 GPIO connector and this adapter to display AGA modes.

---

Commodore-One, for *EXAMPLE*, has a 16-bit (5-6-5) VGA interface:
http://c64upgra.de/c-one/tech/C-One_instant_on_schematics.pdf
(Page6 is the VIDEO circuit)

---

My point is that the DE1 can easily be modified to copy with the required bits/colour to faithfully display AGA screen modes.

Cheers,
Red
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: Dr_Righteous on March 03, 2010, 03:59:56 PM
Theoretically it only needs 18 bits for HAM8 mode... But then I've never understood why there were 24 lines worth of data into the DAC, but AGA couldn't display all 24 bits at once.
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: MskoDestny on March 03, 2010, 04:10:52 PM
Quote from: Dr_Righteous;546005
Theoretically it only needs 18 bits for HAM8 mode... But then I've never understood why there were 24 lines worth of data into the DAC, but AGA couldn't display all 24 bits at once.

AGA is a palette based video chipset. It has 256 palette entries that are each 24-bits wide (8-bits per channel). When using 8 bitplanes, each pixel only takes up 8-bits in chip memory, but this 8-bit value is only used as an index into the palette registers to lookup the appropriate 24-bit color. This is why you need a 24-bit video output to properly display AGA.

HAM8 doesn't change the output color width. It's still 24-bits. It just changes how you select a 24-bit color from the 8-bit data in chip memory. In HAM8 you can either use one of the first 64 entries from the palette or modify the upper 6-bits of one of the 8-bit channels of the 24-bit color that was used for the last pixel.
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: wa9yoz on March 03, 2010, 07:00:41 PM
Doh!...how about an empty A-2000 case?...got 2 of them...sell...trade...Schnapps?
kukuruc@yahoo.com
Tony
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: motorollin on March 03, 2010, 07:51:19 PM
Quote from: bbond007;545949
Could it run the new AGA core?


New AGA core?!

--
moto
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: Dr_Righteous on March 03, 2010, 09:08:58 PM
Quote from: MskoDestny;546007
AGA is a palette based video chipset. It has 256 palette entries that are each 24-bits wide (8-bits per channel). When using 8 bitplanes, each pixel only takes up 8-bits in chip memory, but this 8-bit value is only used as an index into the palette registers to lookup the appropriate 24-bit color. This is why you need a 24-bit video output to properly display AGA.

HAM8 doesn't change the output color width. It's still 24-bits. It just changes how you select a 24-bit color from the 8-bit data in chip memory. In HAM8 you can either use one of the first 64 entries from the palette or modify the upper 6-bits of one of the 8-bit channels of the 24-bit color that was used for the last pixel.


That makes a bit more sense. Sort of like compression, this little chunk of code really means this big chunk of code.
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: bbond007 on March 03, 2010, 11:03:33 PM
Quote from: MskoDestny;546007
AGA is a palette based video chipset. It has 256 palette entries that are each 24-bits wide (8-bits per channel). When using 8 bitplanes, each pixel only takes up 8-bits in chip memory, but this 8-bit value is only used as an index into the palette registers to lookup the appropriate 24-bit color. This is why you need a 24-bit video output to properly display AGA.

HAM8 doesn't change the output color width. It's still 24-bits. It just changes how you select a 24-bit color from the 8-bit data in chip memory. In HAM8 you can either use one of the first 64 entries from the palette or modify the upper 6-bits of one of the 8-bit channels of the 24-bit color that was used for the last pixel.


Well, maybe forget about HAM8 mode. I could see how that would Complicated to implement with only 12bit color.

AGA still offers up to 8bit color in much higher resolution than ECS. Perhaps the 24bit palette register could pick the closest of the available 4096 colors. That and the increased AGA speed might be worth it.
Title: Re: Looking for a case for my Altera-DE1 based Amiga
Post by: ChaosLord on March 04, 2010, 04:38:50 AM
Quote
Perhaps the 24bit palette register could pick the closest of the available 4096 colors.
Yes that can be done, but it looks terrible as all the colors are wrong.