Forums

Again LPC2478, LCD & External Bus Interface

Started by madid87 December 29, 2008
I know by now that it is not possible to execute from external FLASH
memory and simultaneously drive an LCD.

Now, this information is very important. Is it possible to execute
from external SDRAM and drive an LCD with LCD frame buffer in SDRAM
too without LCD flickering? Let's say LCD is 320x240 TFT.

Thank you very much !

An Engineer's Guide to the LPC2100 Series

hi,

You can debug in external SDRAM, if you use IAR , you can modify mac
file and xcl file to config your hardware.

QVGA is no problem to dislpay if you use lpc2478 .

Here are some people done it successfully . You can search
information on this discuss group.

Regards
Vincent

--- In l..., "madid87" wrote:
>
> I know by now that it is not possible to execute from external FLASH
> memory and simultaneously drive an LCD.
>
> Now, this information is very important. Is it possible to execute
> from external SDRAM and drive an LCD with LCD frame buffer in SDRAM
> too without LCD flickering? Let's say LCD is 320x240 TFT.
>
> Thank you very much !
>

--- In l..., "hjiongh" wrote:
> You can debug in external SDRAM

Hi. Thank you for your answer. But I don't understand what debuging
has to do with my question :-( ? Thank you.

All I wanna know is it possible to drive a 320x240 TFT with LCD Frame
buffer and program code in externar x32 SDRAM without LCD flicker? Thanx

Hi, sir

What compiler do you use ?

Regards
Vincent

--- In l..., "madid87" wrote:
>
> --- In l..., "hjiongh" wrote:
> > You can debug in external SDRAM
>
> Hi. Thank you for your answer. But I don't understand what debuging
> has to do with my question :-( ? Thank you.
>
> All I wanna know is it possible to drive a 320x240 TFT with LCD
Frame
> buffer and program code in externar x32 SDRAM without LCD flicker?
Thanx
>

hjiongh wrote:
> --- In l..., "madid87" wrote:
>> --- In l..., "hjiongh" wrote:
>>> You can debug in external SDRAM
>> Hi. Thank you for your answer. But I don't understand what debuging
>> has to do with my question :-( ? Thank you.
>>
>> All I wanna know is it possible to drive a 320x240 TFT with LCD
> Frame
>> buffer and program code in externar x32 SDRAM without LCD flicker?
>
> What compiler do you use ?

And that matters how?

Robert

hi

you wrote:
=========================Now, this information is very important. Is it possible to execute
from external SDRAM and drive an LCD with LCD frame buffer in SDRAM
too without LCD flickering? Let's say LCD is 320x240 TFT.
But I don't understand what debuging has to do with my question :-(
If you use IAR , i think i can help you how to debug in external
SDRAM by modify mac file and xcl file configuration and I executed my
code in external SDRAM successfully without LCD flickering .
Regards
Vincent

--- In l..., Robert Adsett
wrote:
>
> hjiongh wrote:
> > --- In l..., "madid87" wrote:
> >> --- In l..., "hjiongh" wrote:
> >>> You can debug in external SDRAM
> >> Hi. Thank you for your answer. But I don't understand what
debuging
> >> has to do with my question :-( ? Thank you.
> >>
> >> All I wanna know is it possible to drive a 320x240 TFT with LCD
> > Frame
> >> buffer and program code in externar x32 SDRAM without LCD
flicker?
> >
> > What compiler do you use ?
>
> And that matters how?
>
> Robert
>

hjiongh wrote:
> hi
>
> you wrote:

I didn't actually.

> But I don't understand what debuging has to do with my question :-(
> If you use IAR , i think i can help you how to debug in external
> SDRAM by modify mac file and xcl file configuration and I executed my
> code in external SDRAM successfully without LCD flickering .

If you actually read what he wrote, you would find that he did not ask
about debugging. He wanted to know if it was possible, only now have
you indicated that it is.

Robert

--- In l..., Robert Adsett wrote:

> If you actually read what he wrote, you would find that he did not
> ask about debugging. He wanted to know if it was possible, only now
> have you indicated that it is.

:) That's true. But I'm a little suspicious on this issue and
surprised only one answer on this topic? I can't afford to start
developing a system, lose 2 months and money, that will not work in
the end.

If I don't get an reliable answer what should I do, write to NXP
support? Do they usually answer?

> Robert

Ivan

--- In l..., "madid87" wrote:
>
> --- In l..., Robert Adsett wrote:
>
> > If you actually read what he wrote, you would find that he did not
> > ask about debugging. He wanted to know if it was possible, only now
> > have you indicated that it is.
>
> :) That's true. But I'm a little suspicious on this issue and
> surprised only one answer on this topic? I can't afford to start
> developing a system, lose 2 months and money, that will not work in
> the end.
>
> If I don't get an reliable answer what should I do, write to NXP
> support? Do they usually answer?
>
> > Robert
>
> Ivan
>

You can try calling NXP application support. I suppose there is such
a department but I don't really know that. You can send an email to
salesaddresses AT nxp DOT com. That will get you a list of sales
offices. You might start there.

>From time to time, philips_apps posts to this forum. There are some
files that have been posted under that user name. Try to find more
info about the app people.

>From Table 33 of UM10237 (LPC2478 User Manual), you can see that the
priority of gadgets hanging on the AHB Arbiter can be changed such
that the LCD is the highest priority. If the memory cycle time is
much less than the LCD request rate then the DMA plan will probably
work. There is no indication that the DMA system will abort a
transfer in favor of a higher priority request. There would still
need to be some mechanism for retiming the data going to the LCD (I
think...).

Finally, if you are uncertain about using the LPC2478, why do it?
Find a chip that you KNOW will do what you want.

Richard

--- In l..., "rtstofer" wrote:
> Finally, if you are uncertain about using the LPC2478, why do it?
> Find a chip that you KNOW will do what you want.

There is exactly ONE chip on the market that satisfy the following
- LCD Controller
- 32bit external BUS
- nonBGA package

It's 7 years old LH79520 chip (ex Sharp, now NXP). It has no USB, no
Ethernet, no I2C and no flash memory. It would be impossible for me to
add these peripherals externally (x16 FLASH, x32SDRAM, x16 USB OTH and
x16 Ethernet) on a double layer PCB (this is my limit). So this chip
is the only choice and I really have to be sure is it possible to
drive an QVGA 320x240 (240x320) TFT with code execution from external
SDRAM and LCD Frame Buffer in SDRAM too.

I simply can't believe no one tried this ?

THANK YOU VERY MUCH.