AVR as graphic display controller, driving directly row/coloumn

Do you have a question? Post it now! No Registration Necessary

Translate This Thread From English to

Threaded View
Hi -
googled on it but difficult to generate a sucessful "orthogonal" search
criteria.
Can anybody suggest a URL/webpage? The display is 160x240 monochrome,
refresh rate approx. 70Hz, 4-bits data interface and the control signals:
frame, clk, etc. CPU should be an AVR but other also welcome to see
algorithm/program.
I think it should be possible!
- Regards



Re: AVR as graphic display controller, driving directly row/coloumn
Quoted text here. Click to load it

I suspect you won't find anything, because the requirement are more
than a general-purpose processor can comfortably handle. 160x240*70Hz
makes for a pixel clock of 2.7 MHz --- Unless your AVR will be doing
exactly *nothing* else but bit-bang those lines,  it'd have to manage
this is in a strictly synchronized timer interrupt running at 2.7 MHz.

Quoted text here. Click to load it

It's about as "possible" as driving from NY to LA in an electric
wheelchair --- you could do it, but it's a whole lot easier to catch a
flight, instead.


--
Hans-Bernhard Broeker ( snipped-for-privacy@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.

Re: AVR as graphic display controller, driving directly row/coloumn
Hi Hans-Bernhard -
The 70Hz frame rate is AC. So we can save one half of it. 2.7MHz is not
true, the interface shifts 4-bits each time. So I think we should say 2.7MHz
/ 4 / 2 = 340KHz.

The AVR should have it's frame memory in a external SPI memory (clock up to
20MHz is here possible for FRAM memory). The i2c interface connects the AVR
to the main CPU. So we have a nice small LCD controller at the price of a
single EPSON LCD controller.

Should be my first AVR project...

Driving from NY to LA with a electric wheel chair is many more times
possible than to flight with the same gasoline :)

Hans-Bernhard Broeker schrieb in Nachricht ...
Quoted text here. Click to load it



Re: AVR as graphic display controller, driving directly row/coloumn
Quoted text here. Click to load it

Might be of limited use here, but note that the AVR Timer OC feature
can toggle an I/O pin.  That is, you could generate SCK pulses for a
memory chip that will spill out the SDO without CPU interaction.  You
must have good interrupt timing though, to stop SCK exactly when the
line is done :-)

I like this OC feature a lot, and used it for example to supply the
clock to an ISO7816 socket.

Marc

PS: This was a side-note only, I really recommend you to use either a
    readymade LCD controller, or to program a CPLD/FPGA to do the job.
    If you're keen to use an AVR, why not an FPSLIC?

Re: AVR as graphic display controller, driving directly row/coloumn
Interesting note, I will think about it.
Seems you are of the older sort of programmers :)
- Henry

jetmarc schrieb in Nachricht ...
Quoted text here. Click to load it



Re: AVR as graphic display controller, driving directly row/coloumn

Quoted text here. Click to load it

The fpslics are rather expensive compared to standard avr's.

Re: AVR as graphic display controller, driving directly row/coloumn
And the development software is time limited to 4 months. Thereafter they
want BIG money!!
Even you need an external boot device to prog the FPSLIC!
On-chip RAM is nice.
- Henry


Alex Gibson schrieb in Nachricht ...

Quoted text here. Click to load it

The fpslics are rather expensive compared to standard avr's.



Re: AVR as graphic display controller, driving directly row/coloumn

Quoted text here. Click to load it


For homebrew maybe, for a serious project it is not a lot of money.
If you have a nice idea, plenty of time but not a lot of money,
You can write an app note for 6 months free extension.
You can buy another board @ $99 which extends the license 4 months
so there are plenty of options.

The "secure" FPSLIC has FPGA + configurator in the same package.
It is BGA right now, but TQFP is around the corner.


--
Best Regards,
Ulf Samuelsson   ulf@a-t-m-e-l.com
We've slightly trimmed the long signature. Click to see the full one.
Re: AVR as graphic display controller, driving directly row/coloumn
Thanks Ulf for your comments ---
but I always sayed that a development environment for silicone must be free
to my last CPLD vendor (MACH CPLD used). The field application engineer was
at the same thinking but the vendor wants every half a year a new license.
Great on weekend or if you just change the PC...

Great idea to write an app note for money.
- Henry

Ulf Samuelsson schrieb in Nachricht ...
Quoted text here. Click to load it



Re: AVR as graphic display controller, driving directly row/coloumn

Quoted text here. Click to load it

The fpslics are rather expensive compared to standard avr's.

The other issue is is atmel going to keep supporting them ?

Local supplier here recommended against using them
and also said there was a few month lead time even for a small quantity.

Plus the major expense is renewing the software license after
the initial one runs out.either $995 a year or $2500 perpetual license =
with 12 months maintenance

Inital license is 4 months.
http://www.atmel.com/dyn/products/faq_card.asp?faq_id3D%1171
http://www.atmel.com/dyn/products/faq_card.asp?faq_id3D%1197

Alex

Re: AVR as graphic display controller, driving directly row/coloumn
Hi Ulf -
I must rumor to say that if the development cycle is less than 4 months we
have no problem. Or just change the developer each 4 months (external
contract) ...

Interesting to note the following:
AVR standard type max. 16MHz
FPSLIC max. 25MHz
AVR ASIC AVR max. 60MHz

:) Henry

Ulf Samuelsson schrieb in Nachricht ...
Quoted text here. Click to load it



Re: AVR as graphic display controller, driving directly row/coloumn

Quoted text here. Click to load it

035u, Some have tried overclocking with good results....
Can't run the flash at high speed, and the embedded flash process is not as
fast as a pure CMOS.
People seems to like it anyway!


Quoted text here. Click to load it

0.35 u with an infinite number of multiplexers between the CPU and the RAM
gives you that speed.
I generally find that you need more memory than the FPSLIC has to be able to
use the speed.

Quoted text here. Click to load it

Probably not so flexible memory configuration as the FPSLIC. Process?

Quoted text here. Click to load it



--
Best Regards,
Ulf Samuelsson   ulf@a-t-m-e-l.com
We've slightly trimmed the long signature. Click to see the full one.
Re: AVR as graphic display controller, driving directly row/coloumn
Hi Ulf -

Atmel says AVR will run 60MHz in a Atmel ASIC. How should I know what Atmel
can realize in the fab??
- Henry

Ulf Samuelsson schrieb in Nachricht ...
Quoted text here. Click to load it
we
to



Re: AVR as graphic display controller, driving directly row/coloumn

Quoted text here. Click to load it
Atmel


Maybe tell your local contact what you want, and then he will
provide you the alternatives.

--
Best Regards
Ulf at atmel dot com
We've slightly trimmed the long signature. Click to see the full one.
Re: AVR as graphic display controller, driving directly row/coloumn

Quoted text here. Click to load it

IMHO, the AVR may be under-powered to that task. You need also be able to do
something sensible with the screen bitmap in memory.

I'm running a 320 by 240 monochrome LCD directly with an AT91R40008
(ARM7TDMI). The display refresh drive requires about 30 % of the 50 MHz
processor power. The 4  bit interface is connected to the processor bus via
a latch (to even out timing), and the line refresh rate (14.4 kHz) is
generated by an on-chip programmable timer. The timer output is connected to
the FIQ (fast interrupt) input of the processor. The line refresh eats 20 us
each 70 us.

HTH

Tauno Voipio
tauno voipio @ iki fi




Re: AVR as graphic display controller, driving directly row/coloumn
Hi Tauno (forname?) -
Is your prog in Assembler or C?
Regards -
Henry

Tauno Voipio schrieb in Nachricht ...
Quoted text here. Click to load it
do
to
us



Site Timeline