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Forum: µC & Digital Electronics Siemens S65 - LS020 Display MAximum SPI Speed


von Sobak Ava (Guest)


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Hi,

I'm using this display with a LPC2148 ARM7 CPU. Documents on the net 
says S65 mobile phone drives this display at 13MHz SPI clock speed but 
if I use speed about 3.75MHz it does not work.

Is there anyone has used display before at faster speeds?

I've no series resistors between MCU and LCD. MCU works @ 3.3V.

I did not connect 1.8V input of the LCD to anywhere. It is floating 
because I saw some documents say it is not functioning for LS020.

I connected 2.9V input to 3.3V supply.

And my cable is around 10" ( 25cm ) long. Is is a problem?


Regards

von Sobak Ava (Guest)


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I made a mistake.

Please note, my LCD is already running fine with 3.75MHz or lower 
speeds. I want to make it much faster.

von Philipp (Guest)


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Hi,

I've run the LCD at 4MHz without trouble, even with 3k3-Resistors in the 
clock and data wires. But my system runs at 3V and all the display 
supply pins (including 1V8) are connected to this voltage.

Philipp

von Joachim (Guest)


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> And my cable is around 10" ( 25cm ) long. Is is a problem?

Yes!
Probably not with about 3 MHz, but definitely with >10MHz.

The display should work with 12 MHz because in the original mobile 
application, it runs at about 12.5 MHz.

Joachim

von gunni (Guest)


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I run my lcd with 8 MHz and a very short cable.
MCU (Atmega32 Clock 16 MHz) runs with 3,3V.

i want to try it faster with an ARM7.

http://www.youtube.com/watch?v=U1Lo6-4snbM

von shiramoo (Guest)


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I am running on S65 to 10MHz SPI using a PIC24H and no problem up to now 
using a 10cm cable.

von Zippi (Guest)


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I use it in High speed ;).

48Mhz spi (1.8V not connect) 3.0V on power line. Works good. I have no 
problems.

von shiramoo (Guest)


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wow amazing spi performance Zippi  . Please tell me which micro do you 
use ?
My PIC24H is limited to 10MHz.

von Zippi (Guest)


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I Use the AVR32 AT32UC3A Microcontroller. The AVR32 can use spi_clk = 
main_clk, for high speed SPI.

AVR32 max clk is 66 Mhz. overclock(96Mhz).

von Lupin (Guest)


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I used the LS020 with 48 MHz too, everything above 48 MHz wouldn't want 
to work any more.

With 48 MHz the interface is fast enough for fullscreen animations and 
such.

von Zippi (Guest)


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More than 48 Mhz also not work on my board.
I have with 48Mhz and a very simple fullscreen animation more than 
140fps ;).

von Zippi (Guest)


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oh sorry i mean over 120fps in DMA mode.

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