1. Familiarity with the TM4C123 analog to digital converters2. Integrating timers and interrupts into an Analog to Digital Converters (ADC) application3. Understanding the relationship between the clock speed and power dissipation4. Configuring a Universal Asynchronous Receiver/Transmitter (UART) interface5. Understating DMA transfer modes, channels, triggers6. Interfacing a Liquid Crystal Display (LCD) interface to display information for the system7. Learning to write driver files8. Emphasizing the ability to extract information from the datasheet to correctly setup registersObjective of the labFor section A, using the user switches to run the system at different clock speeds and mapping speed to the outputof the internal temperature sensor of the TM4C123 LaunchPad. The different temperatures will be represented bycertain color codes to be displayed on the boards LEDs.For section B, configuring a UART interface.For section C, using DMA to transfer data.For section D, connecting a Liquid Crystal Display (EB-LM4F120-L35) and develop a sketch for it.What you need for the lab1. The EK-TM4C123 Launchpad (http://www.ti.com/tool/EK-TM4C123GXL)2. TM4C123 data sheet (https://canvas.uw.edu/courses/1205180/files/folder/EkTM4C123GXL?preview=49165887)3. Lecture 7 slides4. IAR workbench or other IDE5. ADC (https://en.wikipedia.org/wiki/Analog-to-digital_converter)6. DMA (https://sites.google.com/site/luiselectronicprojects/tutorials/tiva-tutorials/tivadma/understanding-the-tiva-dma)7. UART (https://en.wikipedia.org/wiki/Universal_asynchronous_receiver-transmitter)8. LCD (EB-LM4F120-L35)( http://www.kentecdisplay.com/uploads/soft/Products_spec/EB-LM4F120-L35_UserGuide_04.pdf)Section A. ADCThe ADC ModuleThe TM4C123GH6PM ADC module features 12-bit conversion resolution and supports 12 input channels plus aninternal temperature sensor. The ADC module uses a Successive Approximation Register (SAR) architecture to
deliver a 12-bit, low-power, high-precision conversion value. The range of this conversion value is from 0x000 to0xFFF (0 to 4095). It uses internal signals VREFP and VREFN as references to produce a conversion value from theselected analog input. VREFP is connected to VDDA and VREFN is connected to GNDA, as shown in Figure 1Figure 1 ADC voltage (figure 13-8 of the datasheet)This configuration results in a resolution that can be calculated using the following equation:mV per ADC code = (VREFP VREFN) / 4096Please note that to produce accurate results, the analog input voltages must be within the limits described in table24-33 p.1389 of the data sheet.The Internal Temperature SensorThe built-in internal temperature sensor of the TM4C123 LaunchPad notifies the system when the internaltemperature is too high or low for reliable operation. It converts a temperature measurement into a voltage VTSENSaccording to Figure 2
Figure 2 Internal Temperature Sensor Characteristic (figure 13-11 of the datasheet)The temperature reading from the temperature sensor is a function of the ADC value. The following formulacalculates temperature (TEMP in ) based on the ADC reading (ADC CODE, given as an unsigned decimal numberfrom 0 to 4095) and the maximum ADC voltage range (VREFP VREFN).TEMP = 147.5 ((75 * (VREFP VREFN) ADC CODE ) / 4096)where the ADC CODE is the output of the ADC in the ADCSSFIFOn register.Section A Required TaskYour task is to control the microcontrollers clock speed from the user switches and find the correspondingtemperature generated by the internal temperature sensor. When switch PF0 is pressed, the system clock shouldoperate at 4MHz and if the other switch is pressed, the system clock should operate at 80MHz. A timer shouldtrigger the ADC to read a sample every 1 second and find the corresponding temperature of the CPU. Thetemperature obtained will be displayed by the LEDs based on the following temperature scaleColor PF3 PF2 PF1 value Temperature inCelsiusRed 001 0-17Blue 010 17-19Violet 011 19- 21Green 100 21-23Yellow 101 23-2
Light Blue 110 25-27White 111 27-40Your program could be structured to contain the following functions:1. Timer0_Init function: initialize the timer per instructions are given in lab 2. The GPTMCTL register shouldbe configured to enable the timer to trigger ADC. Since the clock will not be fixed in this lab, its better topass the maximum counter value to this function based on the clock used. For example, in lab 2 we set thecounter value to 16,000,000 for a 16MHz clock so we fixed this value in the Timer0 module which is not thecase in this lab.2. PortF_Init function: initializes the GPIO Port F Pins to accept input from the switches and display output tothe LEDs3. PLL_Init function: initializes the Phase Lock Loop module of the TM4C123 microcontroller based on thesteps explained in lecture 4 slides.4. ADC_Init function: configures the ADC module based on the instructions explained in the datasheet andlecture 7 slides. Note that you may need to insert some delay after the RCGCADC register is configured asthe ADC sometimes requires more than one clock cycle to work especially at high clock rates. Make sure toconfigure the appropriate registers to enable interrupts and allow the ADC to be triggered by the timer. Youalso need to update the vector table in the cstartup_M.c file accordingly5. ADC0_Handler: an interrupt service routine for the ADC0 module. You will use sequencer 3 since you onlyneed one input. In this handler the temperature will be calculated according to the internal temperaturesensor equation and based on the value, the appropriate color should be displayed on the LEDs. Make sureto clear the ADC flag after each conversion.6. the main function: calls initialization functions and checks on the switches all the timeSection B. UART
Universal Asynchronous Receiver/ Transmitter (UART) is a commonly used serial interface. You will be communicatingwith your board via the boards built-in UART communication tool in this class. For this to work, you will need a programon your computer that can serially communicate with the board.We recommend using a program called PuTTY. Once you have PuTTY installed, we need to set up a communication linkwith your Tiva C series board. You will need to make sure that the settings on your board match the communicationssettings in PuTTY. To do this, find your Tiva board in Windows Device Manager. Make note of the COM port that yourboard is associated with; it should say next to the board. Right-click onyour board and click on properties. Navigate to the Port Settings tab. Now, in PuTTY, set theSerial Line field to the COM port you found earlier; for example, mine is currently COM3. Setthe Speed to match your boardthe standard is usually 9600. Set the connection type toSerial, since what you will be using, UART, is a serial communication protocol. Verify the restof the settings on your board match the PuTTY settings under the Serial menu in the lowerleft. From here, we are leaving it up to you to figure out how to get the UART link working with yourboard. We recommend starting by investing PA0 and PA1. The datasheet has all the informationyou need for getting the communication up and going, so use the skills that youve gained thisquarter!
Section B Required Task DeliverablesWe want you to integrate UART communication with section A. Find a way to get yourtemperature result to print to the PuTTY console.For an extra badge, implement a way to send a clock frequency to the board instead of havingto press the buttons to change it.Section C: DMADirect Memory Access (DMA) allows peripherals to access the memory without accessing through the processor.Commonly, you need to save all data into the memory for later usage. Alternatively, we could use DMA to access thedata while the processor works on other operations. Please read this post(https://sites.google.com/site/luiselectronicprojects/tutorials/tiva-tutorials/tiva-dma/understanding-the-tivadma) for more details.Please download and run DMATimerPortRead_4C123.zip from the Canvas(https://canvas.uw.edu/courses/1205180/files/folder/labs).Section C TaskModify the code and blink the three LEDs (one yellow, one green, and one red) in the kits every one second.Section D: LCDIn this section, we use EK-TM4C123GXL to drive a touchscreen LCD (EB-LM4F120-L35). This 3.5 LCD uses 8-bitparallel interface to communicate with the TIVA.HardwareTo get started, plugging the LCD onto the top of the TIVA as the figure 3 shows. The datasheet of EB-LM4F120-L35can be found here (http://www.kentecdisplay.com/uploads/soft/Products_spec/EB-LM4F120-L35_UserGuide_04.pdf). We do not need any jumper wires for the hardware setup.Figure 3 Connecting LCD with TIVA
Write LCD driverDownload and run the starter files from https://canvas.uw.edu/courses/1205180/files/folder/labs, the file nameis lab3_starter.// Runs on LM4F120/TM4C123// Driver for the SSD2119 interface on a Kentec 320x240x16 BoosterPack// Uses all 8 bits on PortB for writing data to LCD// and bits 4-7 on Port A for control signals// Data pin assignments:// PB0-7 LCD parallel data input// Control pin assignments:// PA4 RD Read control signal -// PA5 WR Write control signal | PA7 | PA6 | PA5 | PA4 |// PA6 RS Register/Data select signal | CS | RS | WR | RD |// PA7 CS Chip select signal -// Touchpad pin assignments:// PA2 Y- – -// PA3 X- | PA3 | PA2 | | PE5 | PE4 |// PE4 X+ AIN9 | X- | Y- | | Y+ | X+ |// PE5 Y+ AIN8 – –
Section D Task1) Filled the functions (that marked as TODO) in header file SSD2119.c , see comments for details. Dimensions of the LCD in pixels LCD_GPIOInit LCD_WriteCommand Touch_Init2) Display the temperature data from section A on the LCD, which is the same information that displayedusing URAT in section B.
3) Draw a cube in the center of the screen, the length, width, and depth of the cube are all 0.6 inches. Let thecube rotate, and use the touchscreen to start and stop the rotation of the cube. Print the coordinates of thetouch point on the LCD.4) Draw the same cube in the center of the screen as the sub-task 1. The length, will , and depth of the cube areall 0.6 inches. We fill the cube with the color white. Let the cube rotate. For this sub-task, whenever thetouchscreen is pressed, the fill color will change once. You can use any colors for each press, but the colorsneed to change for each press. Print the RGB color code on the screen.5) FSMi) Recall the traffic light controller in lab 2. Replace the physical al push buttons with two virtual buttonsthat displayed on the LCD. Lets call the start/stop button as virtual button 1, and the button for thepassenger as virtual button 2 for the following sections. You can display the button either vertically orhorizontally. When a virtual button is pressed, the system will respond only if the user holds down thebutton (on the LCD) at least 2 seconds.ii) If the user presses the virtual button 1 (start/stop button, hold for 2 seconds), but not the virtualbutton 2 (passenger button), the system will start with the stop stage (where the red LED is on, andother LEDs are off). After 5 seconds, the system will move to go stage. Then wait for another 5 secondsto change from go stage to stop stage. In other words, the go and stop stage will last for 5 seconds andswitch to each other.iii) If the user presses the virtual button 2 (passenger button, hold for 2 seconds) to indicate a passengertries to across the street, the system will stop the current stage and move the warn stage immediately.The warn stage will last 5 seconds, and move to stop stage.
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