On Tue, 30 Dec 2008 11:00:00 -0000, "Peter Dickerson"
>Back on topic I fount that the bandwidth requirement for 640x480 TFTs was
>too close to the liit while 320x240 wa no problem. In between there is
>480x272 (wide-screen).
Sorry, what chip are U referring to? LPC24XX or LH795XX ?
If LPC, can you confirm that when executing from external x32 SDRAM
driving a 320x240 TFT is not an issue ?
Reply by Peter Dickerson●December 30, 20082008-12-30
"John Devereux" <john@devereux.me.uk> wrote in message
news:87k59i3r9r.fsf@cordelia.devereux.me.uk...
> Frank-Christian Kr�gel <dontmailme@news.invalid> writes:
>
>> Mad I.D. schrieb:
>>> On Mon, 29 Dec 2008 22:38:35 +0100, Frank-Christian Kr�gel
>>>> What display do you use?
>>>
>>> Depending on the budget (there will be about 10 systems produced) it
>>> will be a TFT display with resolution somewhere about 320x240 to
>>> 640x480.
>>
>> If you can live with a display size of max 3.2" you really should look
>> for displays with integrated controller, eg Himax HX8346 or Ilitek
>> ILI9325. These displays don't need a controller at all, 8 or 16 bit
>> data bus, /cs, /rd, /wr, rs (register select) and reset is
>> enough. It's just as simple as driving a character display.
>>
>> Such displays are manufactured by Ampire, LG, Arima, ...
>>
>> Places to start are www.gpeg.com or www.distec.de
>
> "Gloucestershire Physical Exercise & Gyms" ? :)
>
> That's funny; I live there (the county, not the gym unfortunately)!
>
> (Looks like the right link is <http://www.gpegint.com/>, looks
> useful.)
I was brought up in Gloucestershire (Forest of Dean). My mother and two
sisters still live there. Beautiful countryside relative to the flat East
Anglia of my current abode.
Back on topic I fount that the bandwidth requirement for 640x480 TFTs was
too close to the liit while 320x240 wa no problem. In between there is
480x272 (wide-screen).
Peter
Reply by John Devereux●December 30, 20082008-12-30
> Mad I.D. schrieb:
>> On Mon, 29 Dec 2008 22:38:35 +0100, Frank-Christian Krügel
>>> What display do you use?
>>
>> Depending on the budget (there will be about 10 systems produced) it
>> will be a TFT display with resolution somewhere about 320x240 to
>> 640x480.
>
> If you can live with a display size of max 3.2" you really should look
> for displays with integrated controller, eg Himax HX8346 or Ilitek
> ILI9325. These displays don't need a controller at all, 8 or 16 bit
> data bus, /cs, /rd, /wr, rs (register select) and reset is
> enough. It's just as simple as driving a character display.
>
> Such displays are manufactured by Ampire, LG, Arima, ...
>
> Places to start are www.gpeg.com or www.distec.de
"Gloucestershire Physical Exercise & Gyms" ? :)
That's funny; I live there (the county, not the gym unfortunately)!
(Looks like the right link is <http://www.gpegint.com/>, looks
useful.)
--
John Devereux
Reply by ●December 30, 20082008-12-30
Mad I.D. schrieb:
> On Mon, 29 Dec 2008 22:38:35 +0100, Frank-Christian Kr�gel
>> What display do you use?
>
> Depending on the budget (there will be about 10 systems produced) it
> will be a TFT display with resolution somewhere about 320x240 to
> 640x480.
If you can live with a display size of max 3.2" you really should look
for displays with integrated controller, eg Himax HX8346 or Ilitek
ILI9325. These displays don't need a controller at all, 8 or 16 bit data
bus, /cs, /rd, /wr, rs (register select) and reset is enough. It's just
as simple as driving a character display.
Such displays are manufactured by Ampire, LG, Arima, ...
Places to start are www.gpeg.com or www.distec.de
--
Mit freundlichen Gr��en
Dipl.-Ing. Frank-Christian Kr�gel
Reply by Mad I.D.●December 29, 20082008-12-29
On Mon, 29 Dec 2008 22:44:02 +0000, John Devereux
>The LPC2478 is available in QFP - I would try really hard to make it
>work in your application before giving up on it. With just the SDRAM
>as the external bussed device perhaps you can make it work on 2
>layers.
Of course, but I have to be absolutely sure that executing from SDRAM
will not block or flicker the LCD (at least 320x240 TFT). Don't know
what to do now, maybe contact NXP support...
It has to be done on a 2 layer PCB mostly because of the cost.
Reply by John Devereux●December 29, 20082008-12-29
Mad I.D. <madid87@MOOOOVEyahoo.com> writes:
> On Mon, 29 Dec 2008 20:51:35 +0000, John Devereux
> <john@devereux.me.uk> wrote:
>>It is usual in systems with SDRAM to copy the program into it during
>>startup. SDRAM is usually faster than flash, with a wider bus, and is
>>very cheap.
>>So it could be that they can get away with poor performance when
>>executing from flash, since perhaps normally that would only be during
>>startup.
>
> General idea with LH79520 is to use SD card as a "hard drive" for
> program storage. Startup code would sit in FLASH and fill SDRAM with
> program code and then remap controller to start executing from SDRAM.
> My biggest concern right now is could LPC2478 drive a decant TFT
> display with 60Hz refresh rate without flicker? I can't assume a thing
> and lose time and money in the future.
>
>
>>The 79520 is actually quite old now, for a chip of this type. I
>>started using it ~7 years ago. Its still a pretty useful device but I
>>would look very hard at the alternatives now becoming
>>available. Especially if they come with the other peripherals
>>built-in.
>
> Believe me, LH79520 is THE ONLY AVAILABLE controller on the market
> with needed features in nonBGA (double layer PCB limited) package. I
> spent days doing research for suitable IC.
That's the reason I commented - it was the only one 7 years ago too :)
But I still went for a 4 layer board. I think it will be difficult
routing a 32 bit bus system on 2 layers and maintain signal
integrity. You really need a ground plane too, which does not leave
many layers for routing the address/data bus :)
If you know exactly what you are doing, maybe it can be done. But for
more than one device on the bus (external peripherals) it could be
impossible.
The LPC2478 is available in QFP - I would try really hard to make it
work in your application before giving up on it. With just the SDRAM
as the external bussed device perhaps you can make it work on 2
layers.
--
John Devereux
Reply by Mad I.D.●December 29, 20082008-12-29
On Mon, 29 Dec 2008 22:38:35 +0100, Frank-Christian Kr�gel
>What display do you use?
Depending on the budget (there will be about 10 systems produced) it
will be a TFT display with resolution somewhere about 320x240 to
640x480.
Reply by Mad I.D.●December 29, 20082008-12-29
On Mon, 29 Dec 2008 20:51:35 +0000, John Devereux
<john@devereux.me.uk> wrote:
>It is usual in systems with SDRAM to copy the program into it during
>startup. SDRAM is usually faster than flash, with a wider bus, and is
>very cheap.
>So it could be that they can get away with poor performance when
>executing from flash, since perhaps normally that would only be during
>startup.
General idea with LH79520 is to use SD card as a "hard drive" for
program storage. Startup code would sit in FLASH and fill SDRAM with
program code and then remap controller to start executing from SDRAM.
My biggest concern right now is could LPC2478 drive a decant TFT
display with 60Hz refresh rate without flicker? I can't assume a thing
and lose time and money in the future.
>The 79520 is actually quite old now, for a chip of this type. I
>started using it ~7 years ago. Its still a pretty useful device but I
>would look very hard at the alternatives now becoming
>available. Especially if they come with the other peripherals
>built-in.
Believe me, LH79520 is THE ONLY AVAILABLE controller on the market
with needed features in nonBGA (double layer PCB limited) package. I
spent days doing research for suitable IC.
Reply by ●December 29, 20082008-12-29
Mad I.D. schrieb:
> On Mon, 29 Dec 2008 21:30:14 +0100, Mad I.D.
> <madid87@MOOOOVEyahoo.com> wrote:
> /cut
>
> Ohh, there are new replays there. Now I'm not sure could it work with
> code executing only from external SDRAM ? LCD Frame buffer would be in
> SDRAM to. Thank you.
>
> If yes, I just spent 3 weeks with the wrong chip... (I'm a student
> working alone on this)
Reply by John Devereux●December 29, 20082008-12-29
Mad I.D. <madid87@MOOOOVEyahoo.com> writes:
> On Mon, 29 Dec 2008 21:30:14 +0100, Mad I.D.
> <madid87@MOOOOVEyahoo.com> wrote:
> /cut
>
> Ohh, there are new replays there. Now I'm not sure could it work with
> code executing only from external SDRAM ? LCD Frame buffer would be in
> SDRAM to. Thank you.
I was just about to suggest this (without knowing whether it actually
helps on that micro).
It is usual in systems with SDRAM to copy the program into it during
startup. SDRAM is usually faster than flash, with a wider bus, and is
very cheap.
So it could be that they can get away with poor performance when
executing from flash, since perhaps normally that would only be during
startup.
> If yes, I just spent 3 weeks with the wrong chip... (I'm a student
> working alone on this)
The 79520 is actually quite old now, for a chip of this type. I
started using it ~7 years ago. Its still a pretty useful device but I
would look very hard at the alternatives now becoming
available. Especially if they come with the other peripherals
built-in.
--
John Devereux