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Topic: LCD QVGA Arduino shield (Read 21691 times) previous topic - next topic


Thanks for your report  :)

I do not think is a problem reading/writing EEPROM because if you read
the scrX/scrY (RAW touch screen data) when hold a single point,
you can see this X axis reading problem.
EEPROM is used only to store remapped touchscreen/Tft coordinates with
calibraton function.
It seem like a bad ADC convesion from ADS7843, but why Y axis is correct ?
In the modified library, the major difference from original is timing of
SPI Bus, more slow, and reading data from ADS7843 in 3 sigle cycle for each axis,
this permit at the voltage of touchscreen to be stabilized
before ADC reading, indeed, for Y axix it work well.


you're right! the raw data of the x-axis was changing (up to +35) sometimes, when i always touched the same point on the tft. i had a look into the datasheet, but i found nothing, which could be related to our problem.  :(


hi vadda!

i tried the 8-bit mode of the ads7843 today and i didn't get the problems with the x-axis. :) i think the resolution of the 8-bit mode will be enough for my application.


yes, also tried the 8bit mode and work well.
At the end, I discovered a problem with the welds of the touchscreen
on the flat cable. :'(
When it work, with SPI timing lowered at 64/clock there is a good precision.
When touchscreen don't work as expected, I need to press on the flat of the touchscreen, on the left-bottom side of the tft, and when the row data
read, in the lower-left angle, is about 800 on X axis and 880 on Y axis, the precision is good.
Tomorrow I'll try to write at the shop where bought the shield.

Bye  :)


hi vadda,

thanks for your update. please keep me up to date, if you have any news about the touch screen problem.



hey guys and gals.

It is possible that i may gain use of this QVGA screen i pulled from a Compaq Ipaq?


Im kinda new to all of this, i successfully built the KS1080 GLCD sketches and this seems like a whole new monster..

how do i hook this thing up? lol


hi  ;D!

I've buy one last wee ::)k, but someone know how to use it in landscape? Where i need to change the code??




It is possible that i may gain use of this QVGA screen i pulled from a Compaq Ipaq?

Not sure if you're joking or not...

In theory you could, but you would only be able to wire maybe 3 bits per color; maybe leaving enough digital I/O lines left over for the control - and I am not sure if you could drive it fast enough so that it didn't flicker like a banshee.

They talk about the module having a 4 bit interface (4 line?), but then go on and talk about the panel interface; I can't tell if there is a driver chipset on the module or not (if there is, and you can figure out how to hook it up and what the control codes are, you're mostly there).

Also, the big issue on these kinds of panels (really, any of the small consumer junk that clutters our lives with small screens) is the fine pitch connectors; while Digikey or Mouser may have them, they may not, depending on a host of reasons.

I for one am looking for a Mini-USB expanded male connector (with the lines for mic and left/right headphones) to interface with my G1 phone; unfortunately, it looks like you can only get such multi-pin connectors from ??? (who knows) - right now, my only option is to get a cheapo headset for the G1 and cut the cord off.

I have this weird idea of interfacing an Arduino via audio I/O (using some form of FSK audio for data i/o - I have yet to find a way to use the USB port of the G1 in Android, so even if I set up a USB Host shield on the Arduino, I still couldn't do anything)...


I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.


Hey, anybody have this shield working with an Arduino MEGA (ATMEGA 1280 micrcontroller). I tried to connect it, making sure of the following changes: SDA and SCL pins connected to digital 20 and 21 respectively, while the SPI is connected to pins 50-53 (instead of 10-13 on the Duemilanove).
I do not have anything appearing on the screen though, except for a grey-backlit display  :-? :(
Anybody have any luck with this configuration or have any ideas on how to properly connect it?
Thank you so much for your help!!!


On the site is states that there will soon be an update to this product.

Any news on what that update will be. Will it be more expensive?



Also, any possibility of a few details on the display being used and what the driver circuit is etc.?



Any news on this board, like Mowcius said, there seems a new board coming in May.

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