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CCS/LAUNCHXL-CC26X2R1: ST7735S Controller with 0.96inch 80*160 Display

Shyam Shankar79
Expert 2330 points

Part Number: LAUNCHXL-CC26X2R1

Tool/software: Code Composer Studio

Hello All,

I am working with creating a driver for the ST7735S Display controller using the CC26x2R1 Laucnhpad. I followed the Adafruit libraries and have created the driver with the initialization sequence included. But it does not seem to work. 

Is anyone familiar with this display driver on the CC26x2R1 launchpad?

I am attaching the sample CCS project I created herewith.

Regards,

Shyamtest_st7735.rar

  • 0
    TI__Mastermind 24686 points
    Hello Shyam,

    We provide a display driver interface in our driver offerings, but we do not have an implementation for that specific display controller. You can look over our display driver interface here dev.ti.com/.../_display_8h.html

    and a couple of the many examples that use this driver as an interface.
    dev.ti.com/.../_display_dogm1286_8h.html
    dev.ti.com/.../_display_sharp_8h.html

    Regards,
    AB
  • 0 in reply to AB
    Expert 2330 points
    Hi AB,
    Yes I did see those examples and have followed the same to create the driver. However it doesn’t seem to work. I was hoping if anyone familiar with the display controller St7735s being used with the cc26x2r1 would be able to help out. I have attached the code project along with my initial post .
    Regards,
    Shyam
  • 0 in reply to Shyam Shankar79
    Expert 2330 points

    Hello,

    I got the St7735 display to get initialized with the CC26x2R1 . But I noticed that the Ti Grlib draws lines, circles and any figures only in the context foreground color. So everytume I want to draw a line in a particular color I have to change the foreground color first. Say, if I want to draw a white line I have to first set the foreground color to white. Then if the next one has to be red, i have to change the foreground to red.

    Is there any way to achieve this without having to change the foreground everytime?

    Also, currently I am running the Spi at 1MHz and am not able to achiece a sufficient speed in the display. I mean, if I attempt to draw say 10 lines on the display, I am able to see each line being drawn individually. Would increasing the Spi frequency be the only way to achieve better display updates? If so how much could I be able to increase the Spi frequency to in the Cc26x2r1?

    Regards,

    Shyam

  • 0 in reply to Shyam Shankar79
    TI__Mastermind 24686 points
    Helllo Shyam,

    You can change the SPI speed on the launchXL.c or before you open the SPI driver by changing the params.

    As for the driver, I beleive you can override these operations if your screen does not need to do this everytime.

    Regards,
    AB
  • 0 in reply to AB
    Expert 2330 points
    Okay. But how much can the SPI frequency be set to? I mean what could be the maximum value as Master? I changed it from 500KHz to 4MHz and there was sufficient increase in the speed of operation i.e. the speed with which the data is displayed. But beyond that I did not observe any significant change in the speed of operation. The display controller ST7735S also does not mention of any limitation in frequency? So is the TI launchpad cc26x2r1 spi speed limited to 4Mhz as master also?

    Regards,
    Shyam
  • 0 in reply to Shyam Shankar79
    Guru 26200 points

    Shyam Shankar79 said:

    But I noticed that the Ti Grlib draws lines, circles and any figures only in the context foreground color. So everytume I want to draw a line in a particular color I have to change the foreground color first. Say, if I want to draw a white line I have to first set the foreground color to white. Then if the next one has to be red, i have to change the foreground to red.

    Is there any way to achieve this without having to change the foreground everytime?

    What are alternatives for you?

    You can write your own drawCircle(params, color) function
    and in a color change case your function will change a foreground or a "pen" colour.

  • 0 in reply to Shyam Shankar79
    Guru 26200 points

    Shyam Shankar79 said:
    But how much can the SPI frequency be set to?

    SPI bus has no speed limits. The maximum SPI clock speed is dependent on the devices connected to the bus, distances, parasitic capacities, etc. 
    LTC2376 -16 ADC will do 100MHz SPI.

    Shyam Shankar79 said:
    But beyond that I did not observe any significant change in the speed of operation.

    It could be limited by ST7735S controller and/or your device design.

    Shyam Shankar79 said:
    The display controller ST7735S also does not mention of any limitation in frequency?

    Chwck Sitronix sites, forums or just ask them. 

    Shyam Shankar79 said:
    So is the TI launchpad cc26x2r1 spi speed limited to 4Mhz as master also?

    You can find a maximum SCLK reading 19.4.4 SPIM and related sections within this document: www.ti.com/.../swcu185a.pdf .