TWR-LCD board LCD controller

[yoramshacham]

I'm trying to run the TWR-LCD board with the K65 device.

I've tried modifying the K60 tower demo to work with the K65, but so far with no success.

Looking into the K60 demo, I found a reference that mentioned it was running on TWR-LCDSTY board.

It seems that the TWR-LCDSTY was using Solomon-Systech SSD1289  SPI/Parallel LCD controller.

I can't find any reference to the TWR-LCDSTY board on Freescale/NXP product, and I assume it's obsolete by now.

Diving into the current TWR-LCD board schematics, I can't find the SSD1289 (or any other LCD controller).

Any idea how current TWR-LCD should be driven using SPI? which LCD controller is used?

Thanks.

[xiangjun_rong]

Hi, Yoram,

Regarding your question, I suppose that you use Kinetis K65 and want to use LCD to display, but the K65 does not have the on-chip LCD controller module, while the K70 has on-chip LCD controller. In the case, I suggest you use the TWR-K65/TWR-LCD-RGB/TWR-LCD-EPSON/TWR-ELEV. I think the TWR-LCDSTY board is obsolete.

The TWR-LCDC-EPSON board use FlexBus to interface with Kinetis family. But I have not found out the schematics of TWR-LCD-EPSON board on NXP website, maybe the schematics of TWR-LCDC-EPSON has been removed from website by mistake.

Pls refer to the following website:

Epson Display Controller Tower System Module|NXP

BR

Xiangjun Rong

[yoramshacham]

Hi Xiangju,

Thanks for your reply.

We have considered the K70 for the job, however having significantly lower RAM and on chip flash, we're targeting the K65.

Having a simple GUI design, we do not foresee the need for high traffic rates and are inclined to drive GUI over SPI interface rather than external memory interface (as we need to maintain a low pin count).

SPI interface for the graphics should be a valid configuration, to the best of my understanding, and should be supported by K6x+TWR-LCD - is this correct ?

(BTW, I've ported the K60 TWR-LCD demo to the K65 and running it with a logic analyzer on the SPI lines, I do see heavy traffic from the processor side. This made me think that the TWR-LCD board does no contain the same LCD driver (SSD1289) as one used by the K60/TWR-LCDSTY demo.

Regards,

Yoram

[xiangjun_rong]

Hi, Yoram,

For another board TWR-LCD, I have downloaded the user manual of the board. From it's description, it supports External Bus Interface or SPI, I think you can use SPI port to transfer image data between LCD and MCU, but we have to consider the data load.

We can estimate the data load for the LCD:

(data load per second)=(frame rate per second)*X*Y*(bits per pixel). General, the frame rate is 65 frame/per second, assume the LCD is 480*272, Bits per pixel is 24. The data load will be 65*480*272*24=203MBPS, it is huge, that is why we suggest user uses FlexBus to transfer data. If you use SPI, obviously, the LCD can not update as 65 frame per second, you can set the the parameter of the SSD1289 so that it refresh very slowly.

BR

Xiangjun Rong

[yoramshacham]

Hi Xiangjun,

I do not believe SPI communication is required in order to refresh the display every frame.

It stands to reason that the external LCD controller would do it, while the MCU would only send limited display commands upon change via SPI bus.

The thing that puzzles me most, is which external LCD controller is used.

As I mentioned before, it seems the TWR-LCDSTY used the Solomon-Systec SSD1289.

However, in the attached TWR-LCD schematics, I can't find it.

Any idea how the LCD is controlled ?

Regards,

Yoram

[mjbcswitzerland]

Hi

The TWR-LCD's TFT is based on a TRULY TFT2N0369 controller.

Regards

Mark

[yoramshacham]

Hi Mark,

Thanks!

Do you know if there is already an eGui low level driver (preferably SPI driven) for it?

Regards,

Yoram

[LuisCasado · Accepted solution]

Hello,

TWR-LCD uses SSD1289 controller, you can find the eGUI drivers:

https://github.com/Gargy007/eGUI/tree/master/D4D/low_level_drivers/LCD/lcd_controllers_drivers/ssd12...

SPI and Flexbus is supported. Look at the K60 examples.

Luis

[yoramshacham]

Hi Luis,

I was able to get the display up and running on the K65 using the MQX SSD1289 SPI driver - thanks for the tip.

two major things that bother me with documentation:

1. SSD1289 does not show anywhere in the design package (neither schematics nor BOM file)

2. In all tower documentation I looked at:

• TWR-K60N512 Tower Module User's Manual (TWR-K60N512-UM)
• TWR-K65F180M User's Guide (TWRK65F180MUG)
• TWR-LCD User’s Manual (TWRLCDUM)

Elevator connectors B44-B48 are marked PTD11:15 SPI0 pins although PTD11:15 ALT2 function is SPI2 (SPI0 is not muxed on these lines at all).

[LuisCasado]

Hi Yoram Shacham

SSD1289 is embedded in the display. From our documentation point of view, the TWR-LCD schematic includes  TFT2N0451-E as the display used. And the Display datasheet indicates that internal driver IC is the SSD1289.

I hope this clarifies the doc issue.

Luis

[yoramshacham]

Hi Luis,

The K60 examples were for the TWR-LCDSPY board which is now obsolete.

I've tried running the SS1289 drivers with the TWR-LCD but it didn't seem to respond (both SPI and Flexbus).

On top of that, the TWR-LCD schematics does not show the SSD1289, thus the confusion.

Regards,

Yoram