But it seens there's no way for generating video with a good
resolution (say 160x128) with just a PIC solution. I think there's some
OSD generators that could be used for this.
Anyone knows of a video generator chip that could be used with a
microcontroller?
Best regards,
Brusque
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Edson Brusque C.I.Tronics Lighting Designers Ltda
Research and Development Blumenau - SC - Brazil
Say NO to HTML mail http://www.citronics.com.br
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> But it seens there's no way for generating video with a good
> resolution (say 160x128) with just a PIC solution. I think there's some
> OSD generators that could be used for this.
The 18f parts should be able to give you at least twice the horizontal
resolution. (After looking at Rickard's pages, I see that he's running an
f84 at 12Mhz - so you should be able to get a little more than 3 times
more resolution with an 18f device).
On Saturday 05 April 2003 10:19 am, Edson Brusque wrote:
> Hello,
>
> I've seen the pages about PONG on a PIC by Rickard Gunie
> (http://www.efd.lth.se/~e96rg/mc/mc.html#softvideo) and found it
> very interesting.
>
> But it seens there's no way for generating video with a good
> resolution (say 160x128) with just a PIC solution. I think there's
> some OSD generators that could be used for this.
Are you sure?
Remember, you have two shift registers: the I2C/SPI one and the UART.
Either or both could be used to produce a faster bit stream.
Plus, you can get a PIC to run at 40MHz (I'd use an 18F).
On Saturday 05 April 2003 11:08 am, Ned Konz wrote:
> On Saturday 05 April 2003 10:19 am, Edson Brusque wrote:
> > Hello,
> >
> > I've seen the pages about PONG on a PIC by Rickard Gunie
> > (http://www.efd.lth.se/~e96rg/mc/mc.html#softvideo) and found it
> > very interesting.
> >
> > But it seens there's no way for generating video with a good
> > resolution (say 160x128) with just a PIC solution. I think
> > there's some OSD generators that could be used for this.
>
> Are you sure?
>
> Remember, you have two shift registers: the I2C/SPI one and the
> UART. Either or both could be used to produce a faster bit stream.
>
> Plus, you can get a PIC to run at 40MHz (I'd use an 18F).
Plus, you can use the two PWM outputs to generate the H sync and
blanking signals, thereby saving some processor time.
You can then do V sync and blanking by wiggling other I/O lines (you
can count lines from the Timer2 interrupt).
>>Remember, you have two shift registers: the I2C/SPI one and the
>>UART. Either or both could be used to produce a faster bit stream.
are you sure? How could I manipulate the start/stop bits?
>>Plus, you can get a PIC to run at 40MHz (I'd use an 18F).
I think bit banging is possible:
Timing for 160 pixels on a line: 52us/160 = 325ns
But full graphics can't be made on a PIC18F252:
RAM usage: (160x128)/8 = 2560bytes
It would be a lot of effort. I would preffer a ready made solution.
Phillips have some OSD generator chips, but I can't find it on any
store. ST have the STV5730, it could be an option.
Best regards,
Brusque
--
-----------------------------------------------------------------
Edson Brusque C.I.Tronics Lighting Designers Ltda
Research and Development Blumenau - SC - Brazil
Say NO to HTML mail http://www.citronics.com.br
-----------------------------------------------------------------
On Saturday 05 April 2003 02:12 pm, Edson Brusque wrote:
> Hello Ned,
>
> >>Remember, you have two shift registers: the I2C/SPI one and the
> >>UART. Either or both could be used to produce a faster bit
> >> stream.
>
> are you sure? How could I manipulate the start/stop bits?
There are no start or stop bits with either synchronous serial or SPI.
> >>Plus, you can get a PIC to run at 40MHz (I'd use an 18F).
>
> I think bit banging is possible:
> Timing for 160 pixels on a line: 52us/160 = 325ns
> But full graphics can't be made on a PIC18F252:
> RAM usage: (160x128)/8 = 2560bytes
That assumes that you have bit-addressable graphics. However, if you
have a character generator scheme with the actual bitmaps in Flash,
you only need to save the indexes into the character generator.
It mostly depends on what you're doing. If you're just trying to
produce a text display or a simple digital oscilloscope display, you
don't have to have full bit addressability.
> are you sure? How could I manipulate the start/stop bits?
You don't. Use the USART in synchronous mode. You write a byte at a time
and it shifts out each bit in sequence with no start bits, stop bits, or
anything else between bytes.
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Embed Inc, embedded system specialists in Littleton Massachusetts
(978) 742-9014, http://www.embedinc.com
My experience with the SPI/I2C is that it always inserts at least one extra
clock between consecutive bytes of data.
However, you can configure a USART in sync mode and send bits directly head
to tail. I have written a display generator using this trick that displays
mixed graphics and text, including some simple animations. The only hardware
in addition to the PIC and crystal is a couple of resistors!
I get one pixel for each instruction time, so on a 40MHz PIC18 I am able to
get 635 pixel times per horizontal scan line (not all of which are visible
of course)..
mitvma.mit.edu with SET PICList DIGEST in the body
