AVR as graphic display controller, driving directly row/coloumn

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.

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 (broeker@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.

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

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 >> Can anybody suggest a URL/webpage? The display is 160x240 monochrome,

Hi Tauno (forname?) - Is your prog in Assembler or C? Regards - Henry

Tauno Voipio schrieb in Nachricht ...

do

to

us

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?

Interesting note, I will think about it. Seems you are of the older sort of programmers :)

- Henry

jetmarc schrieb in Nachricht ...

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

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.

Alex

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 ...

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

"Henry" skrev i meddelandet news:3f75dcb6 snipped-for-privacy@news.arcor-ip.de...

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
This is a personal view which may or may not be
share by my Employer Atmel Nordic AB

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 ...

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 ...

"Henry" skrev i meddelandet news:3f8332e1 snipped-for-privacy@news.arcor-ip.de...

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! 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.

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

--
Best Regards,
Ulf Samuelsson   ulf@a-t-m-e-l.com
This is a personal view which may or may not be
share by my Employer Atmel Nordic AB

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 ...

we

to

Atmel

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

--
Best Regards
Ulf at atmel dot com
These comments are intended to be my own opinion and they
may, or may not be shared by my employer, Atmel Sweden.