User manual
Table Of Contents
- Chapter 1. Overview
- 1.1 Introduction
- 1.2 Highlights
- 1.3 PICDEM™ Lab Development Kit Contents
- 1.4 PICDEM™ Lab Development Board Construction and Layout
- 1.5 Target Power
- 1.6 Connecting the PICkit™ 2 Programmer/Debugger
- 1.7 Solderless Prototyping Area Strip Configuration
- Chapter 2. Getting Started
- 2.1 Introduction
- 2.2 Prerequisites
- 2.3 The Software Control Loop
- 2.4 MPLAB® IDE Download Instructions
- 2.5 Installing the Included Lab Files
- Chapter 3. General Purpose Input/Output Labs
- 3.1 Introduction
- 3.2 General Purpose Input/Output Labs
- 3.3 GPIO Output Labs
- 3.3.1 Reference Documentation
- 3.3.2 Equipment Required for GPIO Output Labs
- 3.3.3 PICDEM Lab Development Board Setup for GPIO Output Labs
- Figure 3-1: PICDEM Lab Schematic for GPIO Output Labs
- 3.3.4 Lab 1: Light LEDs
- Figure 3-2: MAIN() Software Control Loop Flowchart for Lab 1
- Figure 3-3: Step One
- Figure 3-4: Step Two
- Figure 3-5: Step Three
- Figure 3-6: Step Four
- Figure 3-7: Summary
- Figure 3-8: Project Window
- Figure 3-9: PICkit 2 PROGRAMMER/DEBUGGER TOOLBAR
- Figure 3-10: Lab 1 LED Output
- 3.3.5 Lab 2: Flash LEDs (Delay Loop)
- Figure 3-11: Main() Software Control Loop Flowchart for Lab 2
- Figure 3-12: Timing() Delay Routine Flowchart for Lab 2
- 3.3.6 Lab 3: Simple Delays Using Timer0
- Equation 3-1: TMR0 Overflow Period using FOSC/4
- Equation 3-2: TMR0 Overflow Period when including the Prescaler
- Equation 3-3: Calculating a TMR0 PreLoad Value to generate a 10mS Overflow Period
- Figure 3-13: Delay_10mS() using Timer0
- Equation 3-4: Maximum TMR0 Overflow Period
- Figure 3-14: Delay_1S() using Timer0
- 3.3.7 Lab 4: Rotate LEDs
- Figure 3-15: Main() Software Control Loop Flowchart for Lab 4
- Figure 3-16: Decide() Flowchart for Lab 4
- Figure 3-17: Results of Do_Output()
- 3.4 GPIO Input Labs
- 3.4.1 Reference Documentation
- 3.4.2 Equipment Required for GPIO Input Labs
- 3.4.3 PICDEM Lab Development Board Setup for GPIO Input Labs
- Figure 3-18: PICDEM Lab Schematic for GPIO Input Labs
- 3.4.4 Lab 5: Adding a Push Button
- Figure 3-19: Main() Software Control Loop Flowchart for Lab 5
- Figure 3-20: Get_Inputs() Software Flowchart for Lab 5
- Figure 3-21: Delay_5mS() Software Flowchart for Lab 5
- Figure 3-22: Decide() Software FlowChart for Lab 5
- 3.4.5 Lab 6: Push Button Interrupt
- Figure 3-23: Main() Software Control Loop Flowchart for GPIO Lab 6
- Figure 3-24: pb_pressISR() for Lab 6 Showing Switch Debounce
- 3.4.6 Lab 7: Push Button Interrupt-on-Change
- Figure 3-25: pb_pressisr Flowchart for Lab 7
- 3.4.7 Lab 8: Using Weak Pull-Ups
- Chapter 4. Comparator Peripheral Labs
- 4.1 Introduction
- 4.2 Comparator Labs
- 4.2.1 Reference Documentation
- 4.2.2 Comparator Labs
- 4.2.3 Equipment Required
- 4.2.4 Lab 1: Simple Compare
- Figure 4-1: Schematic for Comparator Lab 1
- Figure 4-2: Main() software Control Loop Flowchart for Comparator Lab 1
- 4.2.5 Lab 2: Using the Comparator Voltage Reference
- Equation 4-1: CVref Output Voltage
- Equation 4-2: Calculating a 2.5V Internal Reference (Low-Range Method)
- Figure 4-3: Schematic for Comparator Lab 2
- 4.2.6 Lab 3: Higher Resolution Sensor Readings Using a Single Comparator
- Figure 4-4: Basic Relaxation Oscillator Circuit
- Figure 4-5: Schematic for Comparator Lab 3
- Figure 4-6: Main() software Control Loop Flowchart for Comparator Lab 3
- Figure 4-7: TMR0_ISR Flowchart for Comparator Lab 3
- Chapter 5. Analog-to-Digital Converter Peripheral Labs
- 5.1 Introduction
- 5.2 ADC Labs
- Figure 5-1: Schematic for ADC Lab 1
- Figure 5-2: Main() software Control Loop Flowchart for Comparator Lab 1
- Figure 5-3: Main() software Control Loop Flowchart for Comparator Lab 1
- Figure 5-4: ADC Result Bit Significance
- Figure 5-5: Schematic for ADC Lab 2
- Figure 5-6: Main() software Control Loop Flowchart for ADC Lab 2
- Appendix A. Schematic
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Lab Development Board User’s Guide
DS41369A-page 42 © 2009 Microchip Technology Inc.
FIGURE 3-21: DELAY_5MS() SOFTWARE FLOWCHART FOR LAB 5
The RA2 pin voltage is then checked again. If still low, a push button press is indicated
and the direction bit variable is toggled. Otherwise, the direction value stays the
same.
The Decide() then uses the current direction value to determine which direction
to shift the contents of the LED_Output global variable. The Decide() software
flowchart is shown in Figure 3-22.
Delay_5mS()
T0IF = 1
(i.e., TMR0 overflow)
?
END
Clear the Timer0 overflow
flag (T0IF)
YES
NO
Preload the Timer0 result
register (TMR0) with 100
Timer0 configured in the Initialize() as fol-
lows:
• Using the internal F
OSC/4 (4MHz/4) clock
source
• TMR0 increments on low-to-high transition
of F
OSC/4
• Prescaler configured for 1:32
Desired Timer0 Overflow Rate = (4/F
OSC) x number of counts to overflow x prescaler
5mS = 1μSeconds x (256 – TMR0 preload value) x 32
TMR0 preload value = 256 – 5mS = 99.75 rounded to 100
1μSeconds x 32
TMR0 preload value determined as follows: