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GLCO Driver Display with Logic Analyzer as Appliaction

Problem Statement

Design Logic Analyzer as an application to study the interfacing of kentec QVGA touch screen graphics display with TIVA c series launchpad.

Resources

  • TIVA C Series Microcontroller (TM4C123GH6PM).
  • Kentec QVGA Touch Screen Graphics Display.
  • Code Composer Studio IDE.
  • GCC.

Project Overview

The project demonstrate the design of portable 4 channel logic analyzer.The 4 channels are sampled and captured for the given time period from user.Then these waveforms are displayed on LCD screen where you can interactively diagnose the waveform of each channel by zoom in or zoom out and also by traversing through the waveform.

Block Diagram

The block diagram of the system is as shown below:

Block Diagram

 

 

 

 

 

 

 

 

 

 

 

 

Description

  1. Channel 1 input.
  2. Channel 2 input.
  3. Channel 3 input.
  4. Channel 4 input.
  5. Power supply to Display.
  6. Ground to Display.
  7. Reset.
  8. SPI clock input for LCD.
  9. Chip select signal input for LCD.
  10. SPI data input for LCD.
  11. Resistive touch screen data input for micro-controller.

Understanding GLCD interfacing

Introduction

The BOOSTXL-K350QVG-S1 Kentec QVGA Display BoosterPack is an easy-to-use plug-in module with a touch-screen color display.We can use this BoosterPack to start developing applications using the 320×240-pixel TFT QVGA display with resistive touch screen.It uses SPI for communication.

Key Features

  1. Kentec TFT LCD (part number: K350QVG-V2-F)
    • 3.5-inch QVGA (320×240 resolution)
    • SPI communication
    • 4-wire resistive touch screen
    • White LED backlight
  2. LED backlight driver circuit
  3. Complies with the BoosterPack standard for use with 20- and 40-pin LaunchPads.

BOOSTXL-K350QVG-S1 Interface

The pin connections to EK-TM4C123GXL is as shown below in tables.

 

J1 Pin Symbol Description Note
1 3.3 V Power supply
2 NC No connection
3 NC No connection
4 NC No connection
5 NC No connection
6 NC No connection
7 LCD_SCL SPI clock input for LCD
8 (LCD_SDC) 4-wire SPI mode DC input for LCD
9 NC No connection
10 NC No connection

 

J2 Pin Symbol Description Note
11 TOUCH_YN Resistive touch screen terminal (Bottom)
12 NC No connection
13 LCD_SCS Chip select signal input for LCD
14 NC No connection
15 LCD_SDI SPI data input for LCD *
16 RESET Reset signal for MCU
17 NC No connection
18 NC No connection
19 NC No connection
20 GND Ground

 

J3 Pin Symbol Description Note
21 5V Power Supply
22 GND Ground
23 TOUCH_YP Resistive touch screen terminal (Top)
24 TOUCH_XP Resistive touch screen terminal (Left) *
25 NC No connection
26 NC No connection
27 NC No connection
28 NC No connection
29 NC No connection
30 NC No connection

 

J4 Pin Symbol Description Note
31 TOUCH_XN Resistive touch screen terminal (Right)
32 LCD_RST Reset signal input for LCD
33 NC No connection
34 NC No connection
35 NC No connection
36 NC No connection
37 NC No connection
38 NC No connection
39 NC No connection
40 LED_ON/OFF LCD backlight ON/OFF control.
  • *look into description of EK-TM4C123GXL image

The following are the images of GLCD Display,micro-controller and their interface.

 

BOOSTXL-K350QVG-S1

 

 

 

 

 

 

 

 

EK-TM4C123GXL:The yellow circle highlights the R9 and R10 registers.This registers should be removed because for the Tiva C Launchpad / EK-TM4C123GXL application, “LCD_SDI / PB7”has been connected to “TOUCH_XP/PD1” by “R10” on the Launchpad.You must remove “R10” before application

 

 

 

 

 

 

 

 

 

 

 

 

 

Interfacing:LCD is mounted on controller

 

 

 

 

 

 

 

 

 

Implementation

  • Firstly,interface the GLCD display with the TIVA C series launchpad as mentioned above.
  • Once the GLCD is interfaced now we have to provide channels for user to probe the digital signals.We have given four GPIO pins for channels.
  • Now we need to get the time period for which waveforms should be captured.
  • For the given time period we have to sample the channels and store the data in memory.
  • Now we have the data of each channel so we can display it.
  • We have to write callback functions for the various functionality which we provide though the resistive touch screen.
  • The flow chart gives the brief idea of the various functionality which is provided using resistive touch screen.

Sampling Frequency

  • The maximum frequency which we could achieve is 200KHz.

Flow Chart

The whole flow of program is given below in the flow chart.Once the analysis is done and if we want to capture the waveforms again then we have to reset the system.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Problems faced

The boosterpack which is available is designed various Tivaware launchpads.So when we interfaced the GLCD display with EK-TM4C123GXL and run the example codes everything was fine except the touch.The touch was not working.The calibration was not right so,we need to recalibrate the touch as it was giving wrong values for the cordinates of the screen where we touched the display.

Demo and Code

The demo is uploaded in the YouTube channel.It demonstrate the working of the logic Analyzer.The link for video is below.

Logic Analyzer using BOOSTXL-K350QVG-S1 and EK-TM4C123GXL - https://www.youtube.com/watch?v=oQtkA_8_9hM&feature=youtu.be
This is the link for source code - https://github.com/nileshbu7/Logic-Analyzer

Future Scope

  • The Sampling frequency can be improved to increase the resolution of the system.
  • The number of channels can be increased if display size is increased.
  • Additional functionality can also be added like markers, etc.
  • Memory allocation for each channel can be increased so as to store waveforms for longer duration.

References

  • TivaWare™ Peripheral Driver Library (User Guide)
  • Tiva™ TM4C123GH6PM Microcontroller(Datasheet)
  • Tiva™ C Series TM4C123G LaunchPad Evaluation Board(User’s Guide)

Team Members

Akshay Birari.

Nilesh Upadhye.