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LB043WQ1-TD01 LCD with emx module


#1

Hello,

I just got my EMX module.
I started working on the PCB that will host the module and some other stuff. I would like to use this LCD (LB043WQ1-TD01 - http://www.gst-lcd.com/spec/tftspec/LB043WQ1-TD01.pdf) with the EMX module because I already have it on my desk with all the other stuff needed. My question is if works with EMX?
The LCD does not have a vertical sync pin neither a horizontal sync. I think that connecting DATA ENABLE (LCD) with HSYNC (EMX) should work properly but I would really dislike building the PCB and finding out that it actually doesn’t work. So I thought I should ask the PROs first.

So, will it work?
If yes, could you give me a test sample code for my LCD configuration?

Thanks

LE:
Would this config work?

Width = 480
Height = 272

HorizontalBackPorch = 20
HorizontalFrontPorch = 25
HorizontalSyncPolarity = true
HorizontalSyncPulseWidth = 480 //(high for all the line pixels? - datasheet says that must hold at least 10ns but the graphs show otherwise)

OutputEnableIsFixed	= true
OutputEnablePolarity = true
PixelClockDivider = 8 //(9MHz clock)?
PixelPolarity = false
PriorityEnable = false //(is it needed?)

VerticalBackPorch = 7
VerticalFrontPorch = 7
VerticalSyncPolarity = true
VerticalSyncPulseWidth = 2

LE: I investigated further and found out that this display is a DE mode only. So, no hsync/vsync, just DE. From what I can understand, DE is the same as hsync. So it should work with the vsync not connected. Am I missing something?


#2

There is enable pin (DE) that you should use along with clock. You will not use HSYNC and VSYNC.

Your display should work just fine but we do not grantee that. You can check the processor’s datasheet if you need more info on the LCD controller, LPC2478.


#3

Are you saying that LCD EN (T18 on EMX) is DE? I thought that this is for the LCD power (enable/disable). In this case which one is the LCD enable pin? Or it should be routed to GPIO or VCC?
I’ll check the arm controller datasheet.

LE: Checked it. Seems that T18 is LCD DATA ENABLE and pin 60 (P2.0) is LCD PWR. In this case should I route LCD PWR to my lcd (from pin 60) and never use COM2?


#4

Yes enable pin is data enable (DE)


#5

Any suggestion on the power pin? My LCD has a DISPLAY ON/OFF input. From LPC’s datasheet I see that LCD PWR is pin 60 (on EMX - P2.0 on chip) which also is TXD on COM2. Is it safe to connect the LCD PWR pin to EMX pin 60? Or should I use a GPIO pin and set it after the program starts.

Thanks


#6

Your question is related to your display so please contact the display manufacture.

I would assume you can use any IO or ski[ that pin all together but the display manufacture will tell you.


#7

Ok, I’ll see what I can do.
Thanks again for the clear up!


#8

The LCD controller is enabled once pixel clock divider is set different than 0xFF. Right? So to disable it I must write pixel clock divider to 0xFF.
Now, for what sleep levels the LCD controller gets turned off? I couldn’t find this anywhere…

Because my LCD screen needs a power enable (PON) pin, I will control it by software via a GPIO. So PON gets set right after setting the lcd controller configuration (with a little delay) but I must be able to turn off PON before the lcd controller is powered off to avoide any damage to the screen. For this, I used PowerState.OnRebootEvent and PowerState.OnSleepChange events to disable PON but I don’t know what sleep levels turn off the lcd controller (if any).

I finished my custom PCB and tested the debugging via USB and everything works well. Hope I’ll test the LCD panel later today.

Thanks


#9

Quick question: What temperature reaches the EMX module while operating?

LE: I think I fried my EMX module :frowning: . It gets pretty warm (50 degrees celsius) and I have no DOT CLK (stays high). The other LCD signals and the GPIO pins work. :’( And I was so excited…


#10

That is sad. Sorry to hear about that.


#11

Yeah, tell me about it… :’( I don’t event now where was the problem.
Anyway, what temperature reaches LPC2478 during normal operation?

LE: Firmware update and tested again. I have 1.65 V (stable) on the DOTCLK but the freq meter I have says there is no clock. Could it be that my freq meter is wrong? Could this by a power supply issue?


#12

Nothing that si considered,


#13

I’m not really sure I understand what you’re saying… :slight_smile:

I would buy a complete dev kit but they are pretty expensive for me. So I’m thinking of another EMX module. The thing is that I wouldn’t use this LCD since I don’t know if this is the cause of the problem (or forgetting to connect 1 GND pin and 1 VCC pin on the first test, or leaving the board without supply but connected to PC via USB). I would like to use a 4.3" LCD or larger but no bigger resoulution than 480x272 and to be known it works with EMX. Any suggestions?


#14

Hello,

I will receive this days a new EMX module (I also have a unused LCD - same model) so I tought I should give it another try before I give up.
My LCD screen needs the power enable/disable functionality (PON pin on LCD) which needs specific timing (musst be set right after the LCD controller starts working). EMX module can provide proper timing (LPC2478 has it) but it needs to be enabled before the LCD controller starts working. Basically I need to change the mode of the GPIO60 (P2.0) pin via PINSEL4 register, set bits 0:1 to 11 and this will enable P2.0 to be LCDPWR signal.
Now, the question is if there is a way to do this? I could do this with RLP but how can I execute it before the LCD controller is initialized?
So, can this be done?

Thanks


#15

Nobody?
Has anyone ever used a display that needs DE and power on/off signals, with EMX module?


#16

Yes. Our 7" display


#17

Could you please guide me to the connection schematics?


#18

It is not in the product page downloads?


#19

Yes, found it. Thanks

LE: I can’t find what type of LCD panel is used in the 7" module. Could you help?


#20

Your questions are beyond our free support scope. You can either contact the display manufacture of hire GHI consulting to study your display. I hope you understand that reading other manufactures data sheets is not part of our free support.