System-80 Asynchronous 16-bit parallel interface for LCD on iMX6

[DipenPatel1z]

Hi All,

We have to interface LCD module with iMX6 SabreSD board with System-80 Asynchronous 16-bit parallel interface. But looking at drivers/mxc/ipu3/ipu_disp.c there is no support for System-80 Asynchronous parallel interface.

If any one have tried this interface before or has some knowledge on how to make driver for it please share your thoughts. Reference manual has not elaborated about this interface either.

Any help is appreciated.

Regards,

Dipen Patel

[YixingKong]

Dipen

This discussion is closed since no activity. If you still need help, please feel free to reply with an update to this discussion, or create another discussion.

Thanks,

Yixing

[DipenPatel1z]

Hi Yixing,

Okay to close this discussion. We have dropped this interface from our design due to lack of information and support.

[YixingKong]

Dipen

We have not got your response yet and will close the diacussion in 3 days. If you still need help, please feel free to reply with an update to this discussion.

Thanks,

Yixing

[austin-]

I'm also trying to get a system-80 (a.k.a. 80-system, 8080, i80) LCD interfaced to an i.MX6 without having to create all the drivers, framebuffers and such from scratch.  I see in section 37.3.1.2.2 - Display Interface, it says,

• A parallel bidirectional bus interface (for asynchronous access) - up to 32-bit data bus.

     • Compatible with MIPI-DBI standard.

     • Control protocol - either system-80 or system-68K The timing and polarity of the

        signals are programmable.

From: i.MX 6Dual/6Quad Applications Processor Reference Manual, Rev. 0, 11/2012, page 2674

The information in section 37.3.1.2.1.2 - Asynchronous Access, seems important to using the DI with a system-80 LCD, but it doesn't provide any concrete steps to take or even where to look for more information or a keyword to use.  It is defiantly talking about system-80\68 interfaces, because I've never seen a more clear description of how the data bus and control registers are shared in a system-80 interface than the one in the i.MX6 Ref Manual

The asynchronous access requires the specification of an address. The display interface uses "indirect addressing", namely, there is no address bus, and the address, as well as control and configuration commands, are embedded in the data stream. The access procedure - including writing addresses and commands - is managed autonomously by the interface, in one of two ways:

It is advertised... how do I make use of it?

Thanks,

Austin

[varsmolta]

So has anyone figured out how to use MCU 8080 interface with the imx6. Is there a driver out there?

[ottawa-imx6]

Did you get this sorted out?

What is the make/model of LCD?

[DipenPatel1z]

HI Ottawa,

Nope. We are still trying. Any help is welcome. So far iMX6 Reference manual is not clear on how to program/initialize Async parallel LCD interface and latest BSP V 3.0.35 also does not have any support for Async parallel LCD interface.

Regards,

Dipen Patel

[ottawa-imx6]

Could you provide a link to the lcd datasheet?

[DipenPatel1z]

HI Ottawa,

Please find the attached Datasheet of LCD. We are using 8080 MCU 16 bit interface. Also attached is controller's datasheet.

Regards,

Dipen Patel

[ottawa-imx6]

I see that the controller supports rgb interface, but assume that this lcd is fixed to use only 8080.

If you can get an lcd that has an rgb interface then writing the driver and init would be pretty straightforward.

If you havent already purchased these lcds in qty, I would suggest looking for one that is rgb interface 16 or 18 bit. There are hundreds of these types of lcds on alibaba for very low prices.

If you only need a few, I may be able to help as I have some leftovers from other projects.

The lcd is hooked up directly to the imx rgb lines (plus hsync vsync clock etc.) and an spi port does the lcd init sequence once at startup.

I have done a few like this, but unfortunately cannot help with the 8080.

One trick I use to generate the init code is to use a standalone avr chip (arduino for example) while setting it up. It makes debugging the specific spi init sequence easier.

Cheers

[anandrajendran]

ottawa-imx6 !

Hi Ottawa,

It would be of great help if you can share the details on the steps for interfacing a parallel RGB666 display that takes configuration for initialization through SPI.

I am trying to interface a 1280*480 chimei TFT LCD display to the parallel port of freescale sabreduallite-sdp eval board. The display needs a power-up/shutdown sequence of voltages and SPI for initial configuration in addition to the DISP0 signals for RGB666, HSYNC, VSYNC etc from the on board display extension port.

Thanks,

Anand

[DipenPatel1z]

HI Ottawa,

Yes even we would also go with RGB interface. But customer has finalized this LCD and interface too. So we have no choice but to make sure it works.

Regards,

Dipen Patel

[YixingKong]

Dipen

Has your question been answered? If yes, we will close your discussion.

Regards,

Yixing

[ottawa-imx6]

I wish you luck in that case.

How many lcd modules have been pre purchased before testing? Perhaps you can sell them back.

[admin]

pejmankalkhoran

[VladanJovanovic]

On older i.MX devices there was a block called SLCD which allowed interfacing to System-80 and 68k type displays. There is no such module on newer devices as this interface is not used that often any more (especially for larger displays).

So if you'd like to connect it to i.MX 6, I'd suggest to check if it would be possible to connect it to EIM bus (external memory bus). You'd need to check if timings and necessary signals can fit into what EIM generates.

Other, less elegant but quite simple, option is to simulate System-80 on GPIOs, where you would manually generate all necessary signals. It wouldn't be very fast, but System-80 is usually not used for displays that need fast updates.

Vladan