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Topic: New Himax HX8347-A TFT and some confusion (Read 3678 times) previous topic - next topic

lorenjz

Hello,

I just recieved a new display.  The description on ebay says this about it:

Quote
Specifications:
3.2" inch TFT LCD module integrated a Himax HX8347-A TFT LCD controller and ADS7843 compatible touch screen controller as well as a SD card cage. It is suitable for embedded systems which require display high quality colorful image or video with interactive control and storage purpose. The Module interfaces to microcontrollers via a 2*20 Pin 2.54mm dual row pin header interface , can easily be connected to any microcontroller or FPGA and DSPs.

-- HX8347-A 240RGBx320 a-Si 262K color TFT controller
-- ADS7843 compatible touch panel controller
-- Standard SD card cage
-- Support 16 bit RGB565 format , can connect any 16 bit data bus
-- Onboard 3.3V regulator require a single 5V supply
-- 3.3V I/O voltage level tolerance
-- Module Size : 94(L) * 64 (W)* 14mm(h) including connector


I'm confused about the Line:  "Onboard 3.3V regulator require a single 5V supply"  Does this mean that it's a 3.3v device or a 5v?  I'm guessing that it's a 3V device because of the line:  "3.3V I/O voltage level tolerance"

Any help is greatly appreciated!

Loren

Riva

From the text you posted I would take it to mean the device needs a 5V supply and it has it's own 3.3V regulator to drop the voltage down. The "3.3V I/O voltage level tolerance" implies either the device needs 3.3V level for the I/O pins and connecting to 5V may/will cause damage or 3.3V I/O will work okay.
Do you have a link?
Don't PM me for help as I will ignore it.

lorenjz

Here is a link to the item:  http://www.ebay.com/itm/290794763628?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

The other thing that leads me to believe that it's a 3.3V is that pin2 lists 3.3 by it.  In fact after looking at the ebay page again it says 3v right at the top. 

Thoughts?

Riva

The site does not really help but a quick look at a datasheet for the HX8247-A and it looks like the data lines are only 3.3V tolerant
Quote
Logic voltage (IOVCC): 1.65 ~ 3.3V
Driver power supply (VCI): 2.3 ~ 3.3V

and the power supply is 3.3V
Don't PM me for help as I will ignore it.

lorenjz


lorenjz

Would a voltage divider with a 1k and a 2.2k resistors work to test this?

lorenjz

also would it be possible for me to run this at 4 or 8 bit instead of 16 for testing purposes?

Riva


Would a voltage divider with a 1k and a 2.2k resistors work to test this?

That would push the voltage out of recommended range (assuming the 2.2K is to ground). Maybe better to use something like 1K & 1.5K that should give about 3V. Maybe other on here have different ideas.

Quote
also would it be possible for me to run this at 4 or 8 bit instead of 16 for testing purposes?

Datasheet shows you can only use 8, 16 or 18 bit data bus, alas no 4 bit bus mode.
Don't PM me for help as I will ignore it.

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