Lcd control

A little update.  I have the display semi functional.  I can write colors to the display, but I can not write to a particular pixel.  It appears that the upper left corner is 0,0.  When ever i attempt to write a pixel, or a number of pixels it always starts here.  At least this proves that we have the proper lines connected.

As near as I can tell the display is addressed at 0-ef is first column, and it runs vertically.  When I just write to address 0x202 I get a horizontal line.  I Still need the proper way to write multiple pixels, and the proper way to address them.

Could you post the code you have written thus far so we can get a better idea of how you are addressing the display? In addition, which MCU are you using for this project (just curious)?

we are using a Microchip Pic24FJ256GB110.  I attached the code for the raw drivers, the rest of the application is the microchip graphics demo's.  We have the Lcd connected to porta of the pic.  We are not using the PMP module.  I am controlling each control line individually.  I have been adding debug code into the ResetDevice() routine to isolate the driver from the microchip graphics library.

Attachment: display_tech.c (34.0KB)

Hi,
I was wondering If you had time to look over the attached code and tell us what we are doing wrong. Have you had a chance to get the factory to tell us how the pixel memory is laid out vs the actual display?  Our customer is starting to get a little antsy.

Sabarski,

Apologies for the delay, we will post a reply as quickly as possible. Thank you for posting your code.

Regards,
Forum Admin

Hi Sabarski,

Factory asked the following;
Please kindly confirm the hardware connection. Please kindly check how the IM[2:0] is connected? the correct connection is 011. For the databus, it should connect to the MSB---DB[17:10].

Please let us know if this helps.

HI,
We have the im2:0 pulled 011.  The data bus is connected 17-10, which give us an 8 bit data bus.
We can write to the pixel ram and get color's.  This tells us that we have the connections right, and have the control lines moving the right way to program the setup data to the controller.  

We can not set a GRAM address to set a pixel.  If we write to the gram, it always starts out with the
top left pixel in the display.  Each successive write to the GRAM will color the next pixel to the right.  What we need is a good example of how to set a few pixels on the display, with the proper toggleing of the control lines to make this happen.

Right now we are writing the address to the gram horizontal register, 200, and the vertical register 201.  Then we write the color data to the pixel gram address at 202.   The writes to 200 and 201 do not seem to have any effect.  We need the control line sequence to make this work, and a mapping of the 2 registers to the actual pixels on the screen would be nice. There are a lot of possible permutations on how the control lines should be driven to make this display work properly.  We just need the information on the proper way.

We are running out of time on making this display work with the Microchip Graphics library.

OK, that provides a lot more information. Let me discuss with Engineering today.

200 and 201 are to set the initial value of address counter. You should set 210, 211, 212, 213 to get the right display position.

Let me know if this works. Thanks.

Writing to these registers makes the display behave differently.  Is 0.0 in the upper right corner? I still do not know how to address a pixel on the display.  All I can get is a horizontal line on the top row with the length being the number of writes to 202.

I guess what I really need to make this display work correctly is code, or a flow chart to draw a vertical line located at 25,50,  Then draw a horizontal line at 200,300.  With this information I think that I would be able to figure out how to position the memory pointer enough to port the display over to the microchip graphics library.

Do we have a date yet for the flowchart or example code to write pixels to this display?  Our customer is getting tired of waiting.  All of my attempts to write to this display always start out on the top row. Writing to the window setting registers changed the starting point of the draw.  We need the information of what address is which pixel, and how to write these address's to the display.

Mike was checking in to this with the factory, however he's out of the office today.  Let's see if he can respond early tomorrow morning.

Do we have a date yet for the flowchart or example code to write pixels to this display?  Our customer is getting tired of waiting.

Sorry just the application note with the initialization instruction is currently available.  Have you referred to the ILI9326 spec to see if that can answer some questions?  I have another customer that is currently in the design stage, let me see if he would be interested in joining the forum and if so if he can share what he's learned.

I have looked at the ili9326 spec.  I can write stuff to the display, It does not behave the way it should. Something is wrong, and I don't have the information to fix it. This is why we are asking for a detailed flowchart on how to drive this display.

We have the display hooked up to a microchip explorer 16 board via a custom board that plugs into the pictail connector.  I have a spare board, but I don't have all of the connectors.

Hello,

I may be that "other customer" that Trevor referred to.  I'm not quite as far as Sabarski is as I'm just finishing off the schematic right now.

But I'll echo Sabarski's comments that it would be good to get more information about how to drive this module.  The ILI9326 datasheet is good but I can't see anywhere in the SDT042TFT datasheet where it mentions how the chip is connected (what modes are selected with pullup/down's for instance).  Also, how are the data lines connected?  Are they connected data0 to data0, data1 to data1, ... or some other arrangement?

What I think would be most useful would be to publish the schematic of the TFT circuit.  Perhaps you don't want to give away some details but at least the MPU interface of the ILI9326 needs to be documented along with any configuration settings that effect the operation of the device.

I know that application note shows the signals you sent into the flex cable connector.  But that is assuming a 18-bit interface, and like Sabarski, I'll be using an 8-bit interface so it's not obvious how to hook up.

Cheers,

James.

Hello all,

OK, I take a bit back from my last post.  On closer inspection some of the detail is included in the pinout table.  I looked at the DB17-DB0 section and didn't see any reference to how to configure between all the modes.  Later on (on the next page) the IM2-IM0 section describes the system interface mode including the databus configuration.

From this I'm assuming that DB17-DB0 connect to their respective pins on the ILI9326, though that isn't stated anywhere.

I still think a schematic of the MPU circuit of the TFT would be useful.

Cheers,

James.

All,

I am working with engineering to address the lack of documentation.

Regards,
M

Just wondering how the information from the factory is coming along.  We have to many unknown's right now, and need some solid information to get this project moving forward.