FT81x with ST7789V

[ashrey]

I found this thread, which is quite old and suggests making a new thread, so I did:
http://www.brtcommunity.com/index.php?topic=220.0

There also weren't any definitive answers in that thread, and I amhoping that has changed since it was posted.

I have previously used a FT810 with a natively RGB panel, and am now looking at using a FT811 (48pin) with this panel that has a ST7789V controller on it: https://www.buydisplay.com/2-4-inch-ips-240x320-tft-lcd-display-capacitive-touch-screen

I think I have  the connections correct, and am looking for confirmation:
Panel    FT811
VSYNC    VSYNC
HSYNC    HSYNC
DOTCLK  PCLK
DE      DE
DB17:0  R7:2|G7:2|B7:2
RESET    DISP

The RD, WRX, D/CX, CSX, and TE pins from the panel are all unused

As the other thread asks, it also appears that the ST7789V needs to be configured via SPI before it will work in RGB mode, but then after that, SPI communications to the display are no longer needed, is that correct?

My current design already has several devices on the SPI bus and can't natively support another CS, but if the ST7789V only requires a few SPI instructions for initialization, I can can easily MUX the FT811 CS and use an MCU GPIO to control whether SPI traffic selects the ST7789V or the FT811.

Thanks

[BRT Community]

Hello,

Thank you for your post.

As the other thread asks, it also appears that the ST7789V needs to be configured via SPI before it will work in RGB mode, but then after that, SPI communications to the display are no longer needed, is that correct?

Yes, generally this is correct for such parts (but please verify the in the datasheet) that you would configure the display driver during boot, and once this ahs been completed you wouldn't communicate with it again. After which you can perform the FT81x initialization routine.

For reference, here is some example code that would be called for the ILI9488 configuration on the ME810A-HV35R:
https://github.com/Bridgetek/EveApps/blob/master/common/eve_hal/EVE_ILI9488_FT9XX.c

In regards to the configuration of parts such as the ST7789V, there are two approach's you can utilise.

• The first approach would be to utilise the SPI interface on your MCU to perform the configuration, using a spare CS# signal.

As noted in the previous thread you can get an example of the hardware we use in the ME810A-HV35R datasheet.

But it would also be acceptable to use the approach you has suggested to MUX the CS# line to the ST7789V and the FT811 and control this via a GPIO.

• The second approach would be to bit bang the configuration data from your MCU over spare GPIO pins if you have these available.

This would remove the need for the MUX IC if you have some spare GPIO pins available.


Best Regards,
BRT Community