MPLAB® XC16 USER’S GUIDE
FOR EMBEDDED ENGINEERS
MPLAB® XC16 User’s Guide for Embedded Engineers
INTRODUCTION
This document presents five code examples for 16-bit devices and the MPLAB® XC16
C compiler. Some knowledge of microcontrollers and the C programming language is
necessary.
1.
2.
3.
4.
5.
Turn LEDs On or Off
Flash LEDs Using _delay() Function
Count Up on LEDs Using Interrupts as Delay
Display Potentiometer Values on LEDs Using an ADC
Display EEPROM Data Values on LEDs
A
B
Run Code in MPLAB X IDE
Get Software and Hardware
2015 Microchip Technology Inc.
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MPLAB® XC16 User’s Guide for Embedded Engineers
1. TURN LEDS ON OR OFF
This example will light alternate LEDs on the Explorer 16 board with a
PIC24FJ128GA010 Plug-In Module (PIM). For more information, see Section B. “Get
Software and Hardware”.
see Section 1.1
#include <xc.h>
// PIC24FJ128GA010 Configuration Bit Settings
// For more on Configuration Bits,
// consult your device data sheet
// CONFIG2
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
POSCMOD = XT
OSCIOFNC = ON
FCKSM = CSDCMD
FNOSC = PRI
IESO = ON
// CONFIG1
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
WDTPS = PS32768
FWPSA = PR128
WINDIS = ON
FWDTEN = OFF
ICS = PGx2
GWRP = OFF
GCP = OFF
JTAGEN = OFF
//
//
//
//
//
see Section 1.2
XT Oscillator mode selected
OSC2/CLKO/RC15 as port I/O (RC15)
Clock Switching and Monitor disabled
Primary Oscillator (XT, HS, EC)
Int Ext Switch Over Mode enabled
//
//
//
//
//
//
//
//
Watchdog Timer Postscaler (1:32,768)
WDT Prescaler (1:128)
Watchdog Timer Window Mode disabled
Watchdog Timer disabled
Emulator/debugger uses EMUC2/EMUD2
Writes to program memory allowed
Code protection is disabled
JTAG port is disabled
#define LEDS_ON_OFF 0x55
int main(void) {
unsigned char portValue = LEDS_ON_OFF;
see Section 1.3
// Port A access
AD1PCFG = 0xFFFF;
TRISA = 0x0000;
LATA = portValue;
// set to digital I/O (not analog)
// set all port bits to be output
// write to port latch
return 0;
}
1.1
Header File <xc.h>
This header file allows code in the source file to access compiler- or device-specific
features. This and other header files may be found in the MPLAB XC16 installation
directory in the support subdirectory.
Based on your selected device, the compiler will set macros that allow xc.h to vector
to the correct device-specific header file. Do not include a device-specific header in
your code or your code will not be portable.
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MPLAB® XC16 User’s Guide for Embedded Engineers
1.2
Configuration Bits
Microchip devices have configuration registers with bits that enable and/or set up
device features.
Note:
1.2.1
If you do not set Configuration bits correctly, your device will not operate at
all or at least not as expected.
WHICH CONFIGURATION BITS TO SET
In particular, you need to look at:
• Oscillator selection - this must match your hardware’s oscillator circuitry. If this is
not correct, the device clock may not run. Typically, development boards use
high-speed crystal oscillators. From the example code:
#pragma config FNOSC = PRI
#pragma config POSCMOD = XT
• Watchdog timer- it is recommended that you disable this timer until it is required.
This prevents unexpected resets. From the example code:
#pragma config FWDTEN = OFF
• Code protection - turn off code protection until it is required. This ensures that
device memory is fully accessible. From the example code:
#pragma config GCP = OFF
Different configuration bits may need to be set up to use another 16-bit device (rather
than the MCU used in this example). See your device data sheet for the number and
function of corresponding configuration bits. Use the part number to search
http://www.microchip.com for the appropriate data sheet.
For more about configuration bits that are available for each device, see the following
file in the location where MPLAB XC16 was installed:
MPLAB XC16 Installation Directory/docs/config_index.html
1.2.2
HOW TO SET CONFIGURATION BITS
In MPLAB X IDE, you can use the Configuration Bits window to view and set these bits.
Select Window>PIC Memory Views>Configuration Bits to open this window.
FIGURE 1:
CONFIGURATION WINDOW
Once you have the settings you want, click Generate Source Code to Output and
then copy the pragma directives from the Output window into your code, as was done
in the example code.
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1.3
Port Access
Digital I/O device pins may be multiplexed with peripheral I/O pins. To ensure that you
are using digital I/O only, disable the other peripheral(s). Do this by using the predefined C variables that represent the peripheral registers and bits. These variables are
listed in the device-specific header file in the compiler include directory. To determine
which peripherals share which pins, refer to your device data sheet.
For the example in this section, Port A pins are multiplexed with peripherals that are
disabled by default. The only issue is that the pins default to analog; so, you will need
to set them to digital I/O:
AD1PCFG = 0xFFFF;
// set to digital I/O (not analog)
A device pin is connected to either a digital I/O port (PORT) or latch (LAT) register in the
device. For the example, LATA is used. The variable portValue is assigned a value
that is then assigned to the latch:
LATA = portValue;
// write to port latch
In addition, there is a register for specifying the directionality of the pin – either input or
output – called a TRIS register. For the example in this section, TRISD and TRISB are
used. Setting a bit to 0 makes the pin an output, and setting a bit to 1 makes the pin an
input. For this example:
TRISA = 0x0000;
DS50002446A-page 4
// set all port bits to be output
2015 Microchip Technology Inc.
MPLAB® XC16 User’s Guide for Embedded Engineers
2. FLASH LEDs USING _delay() FUNCTION
This example is a modification of the previous code. Instead of just turning on LEDs,
this code will flash alternating LEDs.
#include <xc.h>
#include <libpic30.h>
see Section 2.1
// PIC24FJ128GA010 Configuration Bit Settings
// For more on Configuration Bits, consult your device data sheet
// CONFIG2
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
POSCMOD = XT
OSCIOFNC = ON
FCKSM = CSDCMD
FNOSC = PRI
IESO = ON
// CONFIG1
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
WDTPS = PS32768
FWPSA = PR128
WINDIS = ON
FWDTEN = OFF
ICS = PGx2
GWRP = OFF
GCP = OFF
JTAGEN = OFF
//
//
//
//
//
XT Oscillator mode selected
OSC2/CLKO/RC15 as port I/O (RC15)
Clock Switching and Monitor disabled
Primary Oscillator (XT, HS, EC)
Int Ext Switch Over Mode enabled
//
//
//
//
//
//
//
//
Watchdog Timer Postscaler (1:32,768)
WDT Prescaler (1:128)
Watchdog Timer Window Mode disabled
Watchdog Timer disabled
Emulator/debugger uses EMUC2/EMUD2
Writes to program memory allowed
Code protection is disabled
JTAG port is disabled
#define LEDS_ON_OFF 0x55
#define LEDS_OFF_ON 0xAA
#define IC_DELAY 1500000
int main(void) {
unsigned char portValue;
// Port A access
AD1PCFG = 0xFFFF; // set to digital I/O (not analog)
TRISA = 0x0000;
// set all port bits to be output
while(1) {
see Section 2.2
portValue = LEDS_ON_OFF;
LATA = portValue; // write to port latch
// delay value change
__delay32(IC_DELAY);
see Section 2.3
// delay in instruction cycles
portValue = LEDS_OFF_ON;
LATA = portValue; // write to port latch
__delay32(IC_DELAY);
// delay in instruction cycles
}
return -1;
}
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2.1
Library Header File
In this example, the delay32 function from the libpic30 compiler library is used. To
access this library, libpic30.h must be included.
2.2
The while() Loop and Variable Values
To make the LEDs on Port A change, a variable portValue is assigned a value in the
first part of the loop, and a complementary value in the second part of the loop. To
perform the loop, while(1) { } was used.
If the main function returns, it means there was an error, as the while loop should not
normally end. There, a -1 is returned.
2.3
The _delay() Function
Because the speed of execution will, in most cases, cause the LEDs to flash faster than
the eye can see, execution needs to be slowed. __delay32()is a library function that
can be used by compiler.
For more details on the delay function, see the 16-Bit Language Tools Libraries
Reference Manual (DS50001456).
DS50002446A-page 6
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MPLAB® XC16 User’s Guide for Embedded Engineers
3. COUNT UP ON LEDs USING INTERRUPTS AS DELAY
This example is a modification of the previous code. Although the delay function in the
previous example was useful in slowing down loop execution, it created dead time in
the program. To avoid this, a timer interrupt can be used.
#include <xc.h>
// PIC24FJ128GA010 Configuration Bit Settings
// For more on Configuration Bits, consult your device data sheet
// CONFIG2
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
POSCMOD = XT
OSCIOFNC = ON
FCKSM = CSDCMD
FNOSC = PRI
IESO = ON
// CONFIG1
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
#pragma config
WDTPS = PS32768
FWPSA = PR128
WINDIS = ON
FWDTEN = OFF
ICS = PGx2
GWRP = OFF
GCP = OFF
JTAGEN = OFF
// Interrupt function
//
//
//
//
//
XT Oscillator mode selected
OSC2/CLKO/RC15 as port I/O (RC15)
Clock Switching and Monitor disabled
Primary Oscillator (XT, HS, EC)
Int Ext Switch Over Mode enabled
//
//
//
//
//
//
//
//
Watchdog Timer Postscaler (1:32,768)
WDT Prescaler (1:128)
Watchdog Timer Window Mode disabled
Watchdog Timer disabled
Emulator/debugger uses EMUC2/EMUD2
Writes to program memory allowed
Code protection is disabled
JTAG port is disabled
see Section 3.1
void __attribute__((interrupt, no_auto_psv)) _T1Interrupt(void){
// static variable for permanent storage duration
static unsigned char portValue = 0;
// write to port latch
LATA = portValue++;
// clear this interrupt condition
_T1IF = 0;
}
int main(void) {
// Port A access
AD1PCFG = 0xFFFF; // set to digital I/O (not analog)
TRISA = 0x0000;
// set all port bits to be output
// Timer1 setup
see Section 3.2
T1CON = 0x8010; // timer 1 on, prescaler 1:8, internal clock
_T1IE = 1; // enable interrupts for timer 1
_T1IP = 0x001; // set interrupt priority (lowest)
while(1);
return -1;
}
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3.1
The Interrupt Function isr()
Functions are made into interrupt functions by using the interrupt attribute. Program
Space Visibility (PSV) should be specified also, and for this simple example no PSV is
used. For more on PSV, see the “MPLAB XC16 C Compiler User’s Guide”
(DS50002071).
The primary interrupt vector specific to Timer 1 is used, _T1Interrupt. Interrupt
Vector Tables for each device are provided in the compiler install docs directory.
Within the interrupt function, the counter portValue is incremented when Timer1
generates an interrupt.
3.2
Timer1 Setup
Code also needs to be added to the main routine to turn on and set up the timer, enable
timer interrupts, and change the latch assignment, now that the variable value changes
are performed in the interrupt service routine.
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MPLAB® XC16 User’s Guide for Embedded Engineers
4 DISPLAY POTENTIOMETER VALUES ON LEDS USING AN ADC
This example uses the same device and the Port A LEDs as the previous example.
However, in this example, values from a potentiometer on the demo board provide Analog-to-Digital Converter (ADC) input through Port B that is converted and displayed on
the LEDs.
Instead of generating code by hand, the MPLAB Code Configurator (MCC) v2.25 is
used. The MCC is a plug-in available for installation under the MPLAB XIDE menu
Tools>Plugins, Available Plugins tab. See MPLAB X IDE Help for more on how to
install plugins.
For MCC installation information and the MPLAB® Code Configurator User’s Guide
(DS40001725), go to the MPLAB Code Configurator web page at:
http://www.microchip.com/mcc
For this example, the MCC was set up as shown in the following figures.
FIGURE 2:
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ADC PROJECT RESOURCES
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FIGURE 3:
DS50002446A-page 10
ADC SYSTEM PROJECT RESOURCE CONFIGURATION
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MPLAB® XC16 User’s Guide for Embedded Engineers
FIGURE 4:
ADC PROJECT RESOURCE CONFIGURATION
FIGURE 5:
ADC PROJECT RESOURCE PIN TABLE
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FIGURE 6:
ADC GPIO PROJECT RESOURCE CONFIGURATION
FIGURE 7:
ADC GPIO PROJECT RESOURCE PIN TABLE
DS50002446A-page 12
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MPLAB® XC16 User’s Guide for Embedded Engineers
FIGURE 8:
ADC GPIO PROJECT RESOURCE PIN SELECTION
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MPLAB® XC16 User’s Guide for Embedded Engineers
When the code is configured as shown in the previous figures, click the Generate
Code button on the MCC tab. Code generated by the MCC is modular. Therefore main,
system and peripheral code are all in individual files. Also, each peripheral has its own
header file.
Note:
After you create a main project, you can either add a main.c template file
before using MCC or you can let MCC add main.c for you.
FIGURE 9:
ADC PROJECT TREE FOR CODE GENERATED BY MCC
Editing of main.c is always required to add functionality to your program. Review the
generated files to find any functions or macros you may need in your code.
DS50002446A-page 14
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MPLAB® XC16 User’s Guide for Embedded Engineers
4.1
main.c Modified Code
The main.c template file has been edited as shown below. Some comments have
been removed as described in < >. Code added to main() is in red.
/**
Generated Main Source File
<See generated main.c file for file information.>
*/
/*
Copyright (c) 2013 - 2015 released Microchip Technology Inc.
All rights reserved.
<See generated main.c file for additional copyright information.>
*/
#include "mcc_generated_files/mcc.h"
unsigned int value = 0;
/*
Main application
*/
int main(void) {
// initialize the device
SYSTEM_Initialize();
while (1) {
see Section 4.2
// Wait for conversion
// and then get result
while(!ADC1_IsConversionComplete());
value = ADC1_ConversionResultGet();
// Shift for MSb
value = value >> 2;
// Write to Port Latch/LEDs
LATA = value;
see Section 4.3
}
return -1;
}
/**
End of File
*/
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4.2
ADC Conversion and Result
MCC sets AD1CON1 bits to turn on the ADC, use automatic sample acquisition, and
use an internal counter to end sampling and start conversion. Therefore main() code
only needs to wait for the conversion to end and get the result.
From the adc1.c module, use the functions:
bool ADC1_IsConversionComplete(void)
uint16_t ADC1_ConversionResultGet(void)
For information on setting up other ADC features, see the dsPIC33/PIC24 Family
Reference Manual, “Section 17. 10-bit Analog-to-Digital Converter (ADC)” (DS61104).
Since only 8 LEDs are available, and the ADC conversion result is 10-bit, the conversion result in the variable value is shifted to display the most significant bits. Some
resolution will be lost.
4.3
Write to Port Latch and LEDs
The ADC conversion result value is displayed on the Port A LEDs.
DS50002446A-page 16
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MPLAB® XC16 User’s Guide for Embedded Engineers
5. DISPLAY EEPROM DATA VALUES ON LEDS
This example uses another Microchip device, the PIC24F32KA304 MCU, with the
Explorer 16 board, to demonstrate how to write to and read from EEPROM Data
(EEData). Read values are displayed on LEDs accessed from three ports.
MPLAB Code Configurator (MCC) v2.25 is used to generate some of the code. To find
out how to install and get the user’s guide for MCC, see:Section 4 “Display
Potentiometer Values on LEDs Using an ADC”.
For this example, the MCC GUI was used to set up the System (oscillator speed, configuration bits, etc.) and the General Purpose I/O (GPIO) for Ports A, B, and C
(Figure 10). However, at this time, there is no EEData device resource available for
16-bit devices.
Code for using the EEData module was found in the device data sheet and the
dsPIC33/PIC24 Family Reference Manual, “Section 5. “Data EEPROM”, both located
on the device web page:
http://www.microchip.com/PIC24F32KA304
FIGURE 10:
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EEDATA PROJECT RESOURCES
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MPLAB® XC16 User’s Guide for Embedded Engineers
FIGURE 11:
DS50002446A-page 18
EEDATA SYSTEM PROJECT RESOURCE CONFIGURATION
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MPLAB® XC16 User’s Guide for Embedded Engineers
FIGURE 12:
EEDATA GPIO PROJECT RESOURCE CONFIGURATION
FIGURE 13:
EEDATA GPIO PROJECT RESOURCE PIN SELECTION
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FIGURE 14:
DS50002446A-page 20
EEDATA GPIO PROJECT RESOURCE PIN TABLE
2015 Microchip Technology Inc.
MPLAB® XC16 User’s Guide for Embedded Engineers
After your code is configured (as shown in the previous figures), click the Generate
Code button on the MCC tab. Code generated by the MCC is modular. Therefore main,
system, and peripheral code are all in individual files. Also, each peripheral has its own
header file.
Note:
After you create a main project, you can either add a main.c template file
before using MCC or you can let MCC add main.c for you.
FIGURE 15:
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EEDATA PROJECT TREE FOR CODE GENERATED BY MCC
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MPLAB® XC16 User’s Guide for Embedded Engineers
The GPIO generated files default to analog input, so they must be changed to digital
input in the pin_manager.c file (Section 5.1).
In addition, because LED connections are not to one port but spread across three, an
additional type definition and code to assign the port pins to the correct LED values are
needed. A header file, LEDs.h (Section 5.2), and a C file, LEDs.c (Section 5.3), have
been added to the project.
As previously mentioned, there is no EEData device resource available in MCC, so
code needs to be added by hand. A header file eedata.h (Section 5.4) and a C file,
eedata.c (Section 5.5), have been added to the project.
The final project tree will appear as shown in Figure 16.
FIGURE 16:
EEDATA PROJECT TREE - FINAL
Editing of main.c is always required to add functionality to your program
(Section 5.6). Review the generated files and additional files to find any functions or
macros you may need in your code.
DS50002446A-page 22
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MPLAB® XC16 User’s Guide for Embedded Engineers
5.1
pin_manager.c Modified Code
The main.c template file has been edited as shown below. Some comments and
generated content have been removed as described in < >. Code changed is in red.
/**
System Interrupts Generated Driver File
<See generated pin_manager.c for file information.>
*/
/*
Copyright (c) 2013 - 2015 released Microchip Technology Inc. All
rights reserved.
<See generated pin_manager.c for additional copyright information.>
*/
/**
Section: Includes
*/
#include <xc.h>
#include "pin_manager.h"
/**
void PIN_MANAGER_Initialize(void)
*/
void PIN_MANAGER_Initialize(void) {
<See generated pin_manager.c for port setup information.>
/********************************************************************
* Setting the Analog/Digital Configuration SFR
********************************************************************/
ANSA = 0x0;
ANSB = 0x0;
ANSC = 0x0;
}
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5.2
LEDs.h Code
Some comments have been removed as described in < >.
/*------------------------------------------------------------------* PICF32KA304 LEDs header
*
* (c) Copyright 1999-2015 Microchip Technology, All rights reserved
*
<See generated header files for additional copyright information.>
*/
/********************************************************************
* Union of structures to hold value for display on LEDs
* LAT_LEDx - bit fields of value
* w - entire value
*******************************************************************/
typedef union {
struct {
unsigned LAT_LED0:1;
unsigned LAT_LED1:1;
unsigned LAT_LED2:1;
unsigned LAT_LED3:1;
unsigned LAT_LED4:1;
unsigned LAT_LED5:1;
unsigned LAT_LED6:1;
unsigned LAT_LED7:1;
};
struct {
unsigned w:16;
};
} LAT_LEDSBITS;
extern volatile LAT_LEDSBITS LAT_LEDSbits;
/* LAT_LEDSBITS */
#define _LED0 LAT_LEDSbits.LAT_LED0
#define _LED1 LAT_LEDSbits.LAT_LED1
#define _LED2 LAT_LEDSbits.LAT_LED2
#define _LED3 LAT_LEDSbits.LAT_LED3
#define _LED4 LAT_LEDSbits.LAT_LED4
#define _LED5 LAT_LEDSbits.LAT_LED5
#define _LED6 LAT_LEDSbits.LAT_LED6
#define _LED7 LAT_LEDSbits.LAT_LED7
#define _LEDS LAT_LEDSbits.w
/********************************************************************
* Function: DisplayValueOnLEDs
* Precondition: None.
* Overview: Display input value on Explorer 16 LEDs
* Input: Value to display
* Output: None.
*******************************************************************/
void DisplayValueOnLEDs(unsigned int value);
/**
End of File
*/
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5.3
LEDs.c Code
Some comments have been removed as described in < >.
/**
Display on LEDs Source File
<See LEDs.c for file description information.>
*/
/*
Copyright (c) 2013 - 2015 released Microchip Technology Inc. All
rights reserved.
<See generated header files for additional copyright information.>
*/
#include "mcc_generated_files/mcc.h"
#include "LEDs.h"
volatile LAT_LEDSBITS LAT_LEDSbits;
/********************************************************************
* Function: DisplayValueOnLEDs
* Precondition: None.
* Overview: Display input value on Explorer 16 LEDs
* Input: Value to display
* Output: None.
*******************************************************************/
void DisplayValueOnLEDs(unsigned int value) {
_LEDS = value;
_LATA9
_LATA10
_LATA11
_LATC8
_LATC9
_LATB12
_LATB2
_LATB3
=
=
=
=
=
=
=
=
_LED0;
_LED1;
_LED2;
_LED3;
_LED4;
_LED5;
_LED6;
_LED7;
}
/**
End of File
*/
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5.4
eedata.h Code
Some comments have been removed as described in < >.
/*------------------------------------------------------------------* PICF32KA304 Data EEPROM header
*
* (c) Copyright 1999-2015 Microchip Technology, All rights reserved
*
<See generated header files for additional copyright information.>
*/
/********************************************************************
* Function: EEData_WTL
* Precondition: None.
* Overview: Write one word of EEData
* Input: Action to take: Erase or Write, Data to write
* Output: None.
*******************************************************************/
void EEData_WTL(unsigned int action, unsigned int data);
/********************************************************************
* Function: EEData_Erase
* Precondition: None.
* Overview: Set up erase of one word of EEData
* Input: None.
* Output: None.
*******************************************************************/
void EEData_Erase(void);
/********************************************************************
* Function: EEData_Write
* Precondition: None.
* Overview: Set up write of one word of EEData
* Input: Data to write
* Output: None.
*******************************************************************/
void EEData_Write(unsigned int data);
/********************************************************************
* Function: EEData_Read
* Precondition: None.
* Overview: Read one word of EEData
* Input: None.
* Output: Value read from EEData
*******************************************************************/
unsigned int EEData_Read(void);
/**
End of File
*/
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5.5
eedata.c Code
Some comments have been removed as described in < >.
/**
Data EEPROM Write and Read
<See eedata.c for file description information.>
*/
/*
Copyright (c) 2013 - 2015 released Microchip Technology Inc. All
rights reserved.
<See generated header files for additional copyright information.>
*/
#include <xc.h>
#include "eedata.h"
#define ERASE_EEWORD 0x4058
#define WRITE_EEWORD 0x4004
int __attribute__ ((space(eedata))) eeData = 0x0;
unsigned int offset = 0x0;
/********************************************************************
* Function: EEData_WTL
* Precondition: None.
* Overview: Write one word of EEData
* Input: Action to take: Erase or Write, Data to write
* Output: None.
*******************************************************************/
void EEData_WTL(unsigned int action, unsigned int data) {
// Set up NVMCON to write one word of data EEPROM
NVMCON = action;
// Set up a pointer to the EEPROM location to be written
TBLPAG = __builtin_tblpage(&eeData);
offset = __builtin_tbloffset(&eeData);
__builtin_tblwtl(offset, data);
// Issue Unlock Sequence & Start Write Cycle
__builtin_write_NVM();
// Wait for completion
while(NVMCONbits.WR);
}
/********************************************************************
* Function: EEData_Erase
* Precondition: None.
* Overview: Set up erase of one word of EEData
* Input: None.
* Output: None.
*******************************************************************/
void EEData_Erase(void) {
EEData_WTL(ERASE_EEWORD, 0);
}
2015 Microchip Technology Inc.
DS50002446A-page 27
MPLAB® XC16 User’s Guide for Embedded Engineers
/********************************************************************
* Function: EEData_Write
* Precondition: None.
* Overview: Set up write of one word of EEData
* Input: Data to write
* Output: None.
*******************************************************************/
void EEData_Write(unsigned int data) {
EEData_WTL(WRITE_EEWORD, data);
}
/********************************************************************
* Function: EEData_Read
* Precondition: None.
* Overview: Read one word of EEData
* Input: None.
* Output: Value read from EEData
*******************************************************************/
unsigned int EEData_Read(void) {
// Set up a pointer to the EEPROM location to be read
TBLPAG = __builtin_tblpage(&eeData);
offset = __builtin_tbloffset(&eeData);
// Read the EEPROM data
return __builtin_tblrdl(offset);
}
/**
End of File
*/
DS50002446A-page 28
2015 Microchip Technology Inc.
MPLAB® XC16 User’s Guide for Embedded Engineers
5.6
main.c Modified Code
The main.c template file has been edited as shown below. Some comments have
been removed as described in < >. Code added is in red.
/**
Generated Main Source File
<See generated main.c for file information.>
*/
/*
Copyright (c) 2013 - 2015 released Microchip Technology Inc.
All rights reserved.
<See generated main.c for additional copyright information.>
*/
#include
#include
#include
#include
"mcc_generated_files/mcc.h"
"eedata.h"
"LEDs.h"
"libpic30.h"
#define IC_DELAY 1000000
unsigned int data_write = 0x0;
unsigned int data_read = 0x0;
/*
Main application
*/
int main(void) {
// initialize the device
SYSTEM_Initialize();
while (1) {
data_write++;
// Erase one word of data EEPROM
EEData_Erase();
see Section 5.7
// Write one word of data EEPROM
EEData_Write(data_write);
// Read one word of data EEPROM
data_read = EEData_Read();
see Section 5.8
// Display result on LEDs
DisplayValueOnLEDs(data_read);
see Section 5.9
// Delay change on LEDs so visible
__delay32(IC_DELAY); // delay in instruction cycles
}
return -1;
}
/**
End of File
*/
2015 Microchip Technology Inc.
DS50002446A-page 29
MPLAB® XC16 User’s Guide for Embedded Engineers
5.7
Erase and Write to EEData
To write a single word in the EEData, the following sequence must be followed:
1. Erase one data EEPROM word.
2. Write the data word into the data EEPROM latch.
3. Program the data word into the EEPROM.
The code to erase and write one word to EEData is found in eedata.c (Section 5.5).
For the PIC24F32KA304 devices, a key sequence needs to be written to NVMKEY (in
NVMCON) before EEData can be erased or written.
Built-in functions are used to simplify coding:
•
•
•
•
unsigned int __builtin_tblpage(const void *p);
unsigned int __builtin_tbloffset(const void *p);
void __builtin_tblwtl(unsigned int offset, unsigned int data);
void __builtin_write_NVM(void);
Details on these functions may be found in the MPLAB XC16 C Compiler User’s Guide
(DS50002071), Appendix G. “Built-in Functions”.
5.8
Read from EEData
For this example, after EEData is written, the word of EEData is read.
The code to read one word to EEData is found in eedata.c (Section 5.5).
Again, built-in functions are used to simplify coding:
• unsigned int __builtin_tblpage(const void *p);
• unsigned int __builtin_tbloffset(const void *p);
• unsigned int __builtin_tblrdl(unsigned int offset);
Details on these functions may be found in the MPLAB XC16 C Compiler User’s Guide
(DS50002071), Appendix G. “Built-in Functions”.
5.9
Display Data on LEDs and Delay
Displaying the data on the demo board LEDs is more involved for this device, as three
ports provide connections to the LEDs. Therefore union and structure data types are
used so that the whole data value can be assigned (LAT_LEDSbits.w) and then individual bits may be accessed so they can be assigned to the correct port pins for display
(e.g., LATAbits.LATA9 = LAT_LEDSbits.LAT_LED0).
The code creating the union and structures is found in LEDs.h (Section 5.2).
The code assigning the port pins to LED values is found in LEDs.c (Section 5.5).
Because the speed of execution will, in most cases, cause the LEDs to flash faster than
the eye can see, the _delay() function is used again (as in Section 2.) to slow
execution.
DS50002446A-page 30
2015 Microchip Technology Inc.
MPLAB® XC16 User’s Guide for Embedded Engineers
A. RUN CODE IN MPLAB X IDE
First, create a project:
1. Launch MPLAB X IDE.
2. From the IDE, launch the New Project Wizard (File>New Project).
3. Follow the screens to create a new project:
a) Choose Project: Select “Microchip Embedded”, and then select
“Standalone Project”.
b) Select Device: Select the example device.
c) Select Header: None.
d) Select Tool: Select your hardware debug tool by serial number (SN),
SNxxxxxx. If you do not see an SN under your debug tool name, ensure that
your debug tool is correctly installed. See your debug tool documentation for
details.
e) Select Plugin Board: None.
f) Select Compiler: Select XC16 (latest version number) [bin location]. If you
do not see a compiler under XC16, ensure the compiler is correctly installed
and that MPLAB X IDE is aware of it. Select Tools>Options,, click the
Embedded button on the Build Tools tab, and look for your compiler. See
MPLAB XC16 and MPLAB X IDE documentation for details
g) Select Project Name and Folder: Name the project.
Now, create a file to hold the example code (unless you have used MCC):
1. Right click on the project name in the Projects window. Select New>Empty File.
The New Empty File dialog will open.
2. Under “File name”, enter a name.
3. Click Finish.
4. Cut and paste the example code from this user’s guide into the empty editor
window and select File>Save.
Build, download to a device, and execute the code by selecting to Debug Run your
code. You will see every other LED lit on the demo board. Click Halt to end execution.
FIGURE 17:
TOOLBAR ICONS
DEBUG RUN
2015 Microchip Technology Inc.
HALT
DS50002446A-page 31
MPLAB® XC16 User’s Guide for Embedded Engineers
B. GET SOFTWARE AND HARDWARE
For the MPLAB XC16 projects in this document, the Explorer 16 board with a PIC24F
PIM is powered from a 9V external power supply and uses standard (ICSP™)
communications. MPLAB X IDE was used for development.
B.1
Get MPLAB X IDE and MPLAB XC16 C Compiler
MPLAB X IDE v3.15 and later can be found at:
http://www.microchip.com/mplabx
The MPLAB XC16 C Compiler v1.25 and later can be found at:
http://www.microchip.com/mplabxc
B.2
Get the MPLAB Code Configurator (MCC)
The MCC v2.25 and later can be found at:
http://www.microchip.com/mcc
B.3
Get PIC® MCU Plug-in Module (PIM)
The PIC MCU PIMs used in the examples are available at the following locations on
the Microchip Technology web site:
PIC24FJ128GA010: http://www.microchip.com/MA240011
PIC24F32KA304: http://www.microchip.com/MA240022
B.4
Get and Set Up the Explorer 16 Board
The Explorer 16 development board and documentation are available on the web site:
http://www.microchip.com/explorer16
Jumpers and switches were set up as shown in the following table.
TABLE 1-1:
JUMPER/SWITCH SELECTS FOR PROJECTS
Jumper/
Selection
Switch
Description
J2
Closed
Closed: Enable LEDs on Port A <RA0:7>
Open: Disable LEDs
J7
PIC24
PIC24: The debug tool communicates directly with PGCx/PGDx or
EMUCx/EMUDx of the PIM or on-board device (determined by S2).
F4550: The debug tool communicates with the on-board PIC18LF4550
USB device.
S2
PIM
PIM or PIC selection
B.5
Get Microchip Debug Tools
Emulators and Debuggers may be found on the Development Tools web page:
http://www.microchip.com/devtools
DS50002446A-page 32
2015 Microchip Technology Inc.
Note the following details of the code protection feature on Microchip devices:
•
Microchip products meet the specification contained in their particular Microchip Data Sheet.
•
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•
Microchip is willing to work with the customer who is concerned about the integrity of their code.
•
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
MICROCHIP MAKES NO REPRESENTATIONS OR
WARRANTIES OF ANY KIND WHETHER EXPRESS OR
IMPLIED, WRITTEN OR ORAL, STATUTORY OR
OTHERWISE, RELATED TO THE INFORMATION,
INCLUDING BUT NOT LIMITED TO ITS CONDITION,
QUALITY, PERFORMANCE, MERCHANTABILITY OR
FITNESS FOR PURPOSE. Microchip disclaims all liability
arising from this information and its use. Use of Microchip
devices in life support and/or safety applications is entirely at
the buyer’s risk, and the buyer agrees to defend, indemnify and
hold harmless Microchip from any and all damages, claims,
suits, or expenses resulting from such use. No licenses are
conveyed, implicitly or otherwise, under any Microchip
intellectual property rights unless otherwise stated.
Trademarks
The Microchip name and logo, the Microchip logo, dsPIC,
FlashFlex, flexPWR, JukeBlox, KEELOQ, KEELOQ logo, Kleer,
LANCheck, MediaLB, MOST, MOST logo, MPLAB,
OptoLyzer, PIC, PICSTART, PIC32 logo, RightTouch, SpyNIC,
SST, SST Logo, SuperFlash and UNI/O are registered
trademarks of Microchip Technology Incorporated in the
U.S.A. and other countries.
The Embedded Control Solutions Company and mTouch are
registered trademarks of Microchip Technology Incorporated
in the U.S.A.
Analog-for-the-Digital Age, BodyCom, chipKIT, chipKIT logo,
CodeGuard, dsPICDEM, dsPICDEM.net, ECAN, In-Circuit
Serial Programming, ICSP, Inter-Chip Connectivity, KleerNet,
KleerNet logo, MiWi, MPASM, MPF, MPLAB Certified logo,
MPLIB, MPLINK, MultiTRAK, NetDetach, Omniscient Code
Generation, PICDEM, PICDEM.net, PICkit, PICtail,
RightTouch logo, REAL ICE, SQI, Serial Quad I/O, Total
Endurance, TSHARC, USBCheck, VariSense, ViewSpan,
WiperLock, Wireless DNA, and ZENA are trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.
SQTP is a service mark of Microchip Technology Incorporated
in the U.S.A.
Silicon Storage Technology is a registered trademark of
Microchip Technology Inc. in other countries.
GestIC is a registered trademark of Microchip Technology
Germany II GmbH & Co. KG, a subsidiary of Microchip
Technology Inc., in other countries.
All other trademarks mentioned herein are property of their
respective companies.
© 2015, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
ISBN: 978-1-5224-0099-8
QUALITYMANAGEMENTSYSTEM
CERTIFIEDBYDNV
== ISO/TS16949==
2015 Microchip Technology Inc.
Microchip received ISO/TS-16949:2009 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Company’s quality system processes and procedures
are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.
DS50002446A-page 33
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DS50002446A-page 34
2015 Microchip Technology Inc.