The old 8088's could pull it off because they had external video driver
chips. The early Macs relied upon the 68K cpu but still had plenty of
external PLDs handling the mundane timing etc.
Look, if you use an external memory bus ARM, a 512KB or more <wide>
SRAM, some logic, and a palette DAC you could display jpegs quite
nicely. Yes, it would be nice if some of the VGA support could be built
right into the ARM and then it would be a simple matter of bolting on
some RAM and away we go.
The single-chip 2138 is probably out of the question for displaying
jpegs as there are better alternatives plus the 512K memory is Flash and
not suitable for frequently updated display memory.
Don't you just hate those cheap products that can display video so
nicely? Of course if you made a million units it would make it a million
times simpler.
*Peter*
jdarling@jdar... wrote:
>I had thought of using something as a driver chip,
but everything I've found is either too costly,
>over my head as far as skills go, or depricated. Course then again this may
be over my head
>too :). Honestly I didn't figure that VGA could be that difficult since
the old 8088's could do it
>and still have time to pull off simple graphics. Maby an FPGA as a driver
would be better,
>but my lack of knowledge in this section of the world puts me at a great
disadvantage.
>
LPC2138, VGA, and SD/MMC
Started by ●July 26, 2005
Reply by ●July 27, 20052005-07-27
Reply by ●July 28, 20052005-07-28
Peter,
Actually I did manage to find an ARM7 with a built in TFT display that
can be easily (Their words not mine) hacked to do VGA with an external
memory chip. Only two problems here :)
1) Its another chip I have to buy and learn
2) The code doesn't leave much processing time to do anything else.
Just in case anyone is curious:
http://www.revely.com/LAB100/LAB100_VGA_App.htm
So I've pretty much given up on the single chip solution. Now I'm
looking into an FPGA/CPLD board that comes with a simple 6 bit DAC and
VRML VGA source code. I'll have to replace the DAC and update the code
for a higher color ratio (god I hope it isn't very difficult to figure
out VRML) but it looks to be the only solution to my problem.
In the end I hope to come up with a simple to use 4, 8, or 16 bit VGA
card that is quite generic and powerful. This way I can use it on my
small 8 bit micros as well as on larger projects. Who knows thou as my
level of expertiese in all these areas is quite minimal. I hope that in
the end the learning experience that I get from the whole project will
be worth it :).
Its always irritating that the big companies can beat us out, but that
doesn't mean I'm not going to try :).
Jeremy
Actually I did manage to find an ARM7 with a built in TFT display that
can be easily (Their words not mine) hacked to do VGA with an external
memory chip. Only two problems here :)
1) Its another chip I have to buy and learn
2) The code doesn't leave much processing time to do anything else.
Just in case anyone is curious:
http://www.revely.com/LAB100/LAB100_VGA_App.htm
So I've pretty much given up on the single chip solution. Now I'm
looking into an FPGA/CPLD board that comes with a simple 6 bit DAC and
VRML VGA source code. I'll have to replace the DAC and update the code
for a higher color ratio (god I hope it isn't very difficult to figure
out VRML) but it looks to be the only solution to my problem.
In the end I hope to come up with a simple to use 4, 8, or 16 bit VGA
card that is quite generic and powerful. This way I can use it on my
small 8 bit micros as well as on larger projects. Who knows thou as my
level of expertiese in all these areas is quite minimal. I hope that in
the end the learning experience that I get from the whole project will
be worth it :).
Its always irritating that the big companies can beat us out, but that
doesn't mean I'm not going to try :).
Jeremy
Reply by ●July 28, 20052005-07-28
Thanks Jeremy, I have had a look at a few different ARMs before but I
tend to reject them for several reasons. The Sharp part has a large pin
count (not excessive) plus no internal Flash which means more chips. If
it had some internal Flash I wouldn't mind and would probably use it. If
I can do it all on-board a chip, then that is the way I prefer.
I know I can easily do an FPGA connected to an external bus ARM plus the
wide RAM but again this means several large chips, multilayers to run
all those connections, etc. Nevertheless, I may have to do one along
these lines just for some hi-res stuff. These tiny single-chippers are
really spoiling me!
*Peter*
jdarling@jdar... wrote:
>Peter,
>
>Actually I did manage to find an ARM7 with a built in TFT display that
>can be easily (Their words not mine) hacked to do VGA with an external
>memory chip. Only two problems here :)
>1) Its another chip I have to buy and learn
>2) The code doesn't leave much processing time to do anything else.
>
>Just in case anyone is curious:
>http://www.revely.com/LAB100/LAB100_VGA_App.htm
tend to reject them for several reasons. The Sharp part has a large pin
count (not excessive) plus no internal Flash which means more chips. If
it had some internal Flash I wouldn't mind and would probably use it. If
I can do it all on-board a chip, then that is the way I prefer.
I know I can easily do an FPGA connected to an external bus ARM plus the
wide RAM but again this means several large chips, multilayers to run
all those connections, etc. Nevertheless, I may have to do one along
these lines just for some hi-res stuff. These tiny single-chippers are
really spoiling me!
*Peter*
jdarling@jdar... wrote:
>Peter,
>
>Actually I did manage to find an ARM7 with a built in TFT display that
>can be easily (Their words not mine) hacked to do VGA with an external
>memory chip. Only two problems here :)
>1) Its another chip I have to buy and learn
>2) The code doesn't leave much processing time to do anything else.
>
>Just in case anyone is curious:
>http://www.revely.com/LAB100/LAB100_VGA_App.htm
Reply by ●July 28, 20052005-07-28
Peter Jakacki <peterjak@pete...> schrieb am Thu, 28 Jul 2005 13:39:54
+1000:
>
> I know I can easily do an FPGA connected to an external bus ARM plus the
> wide RAM but again this means several large chips, multilayers to run
> all those connections, etc. Nevertheless, I may have to do one along
> these lines just for some hi-res stuff. These tiny single-chippers are
> really spoiling me!
How about as simple PLD connected via SPI ?
Ah, maybe not enough RAM on a PLD ?
--
42Bastian Schick
+1000:
>
> I know I can easily do an FPGA connected to an external bus ARM plus the
> wide RAM but again this means several large chips, multilayers to run
> all those connections, etc. Nevertheless, I may have to do one along
> these lines just for some hi-res stuff. These tiny single-chippers are
> really spoiling me!
How about as simple PLD connected via SPI ?
Ah, maybe not enough RAM on a PLD ?
--
42Bastian Schick
