1222 - Kauno technologijos universitetasekaza/rls/rtos_materials/1222.pdf · Data Types short 1bit...

1222 CCSUsing the CCS C Compiler for Rapid Development of

Microcontroller Applications© 2008 Microchip Technology Incorporated. All Rights Reserved. 1222 CCS Slide 1

© 2008 Custom Computer Services Inc., , Microchip Technology Incorporated. All Rights Reserved. 1222 CCS Slide 2

Class Objective

When you finish this class you will:− Be able to use your C knowledge and

write applications using CCS C− Know the ways the CCS C Compiler

speeds up development time− Develop new application and coding

ideas


AgendaCompiler Overview− Design Goals, Compiler ProductsCompiler Methodology− Differences to ‘Common’ C − Data TypesProgramming Details− Required setup, InterruptsBuilt-In Functions− GPIO, Delays, Serial (Asynch, I2C™, SPI)


AgendaHands-on Labs

Lab 1: 0 to blinky LED in 60 secondsLab 2: The CCS IDE DebuggerLab 3: Stopwatch using interruptsLab 4: A/D

Compiler Overview


Design Goals

Ease of use – compile and go!Quick development time (with built-in functions, drivers/libraries, extensive examples)Easy PIC® MCU to PIC MCU migrationOptimization comparable vs. assembly


CCS Command Line Compiler

Product Line:− PCB – Baseline PIC® MCUs − PCM – Mid-Range PIC MCUs − PCH – PIC18 Family PIC MCUs − PCD – PIC24/dsPIC30/dsPIC33 Family− PCX – PIC32 FamilyIntegrates into MPLAB® IDELinker− Can’t create relocatable objectsLinux and Windows versions


PCW – Windows IDE

C Aware EditorDebugging (using a CCS ICD)Integrated RTOSLinker and Re-locatable objectsDocument GeneratorStatisticsFlow Chart Editor


CCS Support PolicyE-Mail / Phone Support− Duration is Unlimited!Updates (new devices, drivers)− Requires Maintenance Contract− Maintenance can be extended at any

periodLarge Customer BaseRapid Releases− Average once per week


CCS ICDIn-Circuit Programmer/DebuggerSerial & USBControl Software− Windows and LinuxCCS PCW IDE for debuggingICD cable is compatible with Microchip MPLAB® ICD2


CCS Development Kits

A combined package that gives a user:− C Compiler− Prototyping Board− ICD− Tutorial Book and Examples− Relevant Parts and Cables

Compiler Demonstration

Hands On Lab #1

Blinky LED


Lab 1 Objectives

Hands-on experience with compilerUse tools and development boardUse CCS Project WizardCreate blinky-LED


Prototyping Hardware

PIC16F877A− ICD Connection− Pot on AN0− Button on RA4− LEDs on RA5, RB4 and RB5− RS232 driver and mini-connector− Header to all GPIO


Lab 1: Project WizardProject Wizard Overview

Creates an initial frameworkAssists in the initial configuration of internal peripheralsConfiguration screen for all internal peripheralsWindows IDE Only


Lab 1: Project WizardStep 1 – Start Compiler IDE

Start the CCS Compiler IDE − Double click on the icon labeled ‘PIC

C Compiler’


Lab 1: Project WizardStep 2 – Start Project Wizard

Start the Project Wizard− File -> New -> Project Wizard


Lab 1: Project WizardStep 3 – File Name Dialog

File name: C:\masters\1222\Lab1\lab1.cPress Save


Lab 1: Project WizardStep 4 – Configuration

You will now be in the Project Wizard DialogIn the General Section:− Select 16F877A under Device− Set oscillator to 20000000 Hz− Select ‘High Speed Osc’ under fuse


Lab 1: Project WizardStep 5 – Enter Code

Press the OK button in the Project WizardInside main(), find the line marked:− //TODO: USER CODE

Replace this line with the following code:while(TRUE){

delay_ms(500);output_toggle(PIN_B5);

}


Lab 1: Project WizardStep 6 – Compile Code

Compile Code − Compile -> Compile


Lab 1: Project WizardStep 7 – Compile Results

Inspect the output window for compile results− You should get 0 Errors


Lab 1: Project WizardStep 8 – Load HEX

Load HEX file with CCS ICD− Click on the ‘Program Chip’ icon on

the ‘Compile’ ribbon, select ICD


Lab 1 Hints

LED will blink at 1Hz rateFollow handoutVerify:− Correct PIC® MCU Selected− Correct FUSEs selected− Correct #use delay() specified− Fix any compile errorsBored? Try “Extra Credit”

Compiler Methodology


Differences to ‘Common’ CCase in-sensitive− #case will make it case sensitiveVariables not initialized to zero− #zero_ram inits all variables to 0const places variable into ROMBy default, const strings cannot be parameter− SomeFunc(“Hello”) is usually illegal− #device PASS_STRING=IN_RAM#device ANSI


ANSI Non-Compliance

No fopen(), fclose(), etc− fprintf() supported, methodology a

little differentprintf() formatting string must be known at compile timeRecursion not allowed on all PIC®

MCUs


Data Types

1bit1bitshortUnsigned 8bitUnsigned 8bitchar

Signed 64bitUnsigned 32bitlong long

IEEE 64bitNO SUPPORTdoubleIEEE 32bitMCHP 32bitfloat

Signed 32bitUnsigned 16bitlongSigned 16bitUnsigned 8bitint

PCDPCB/PCM/PCH


Data Types#type can change default size− #TYPE SHORT=8, INT=16, LONG=32

Optimization Tips− Use only one float type− Use ‘int’ as much as possibleNon-standard data types− int1 int8 int16− int32 int48* int64*− float32 float48* float64* (PCD ONLY)

− __address__


Fixed Point Decimal

Decimals with integers, not floats!− Faster, Smaller− 100% precisionStores value in 10y powerDeclaration:[type] _fixed(y) [declarator]int16 _fixed(2) money


Fixed Point Examples

int16 _fixed(2) money;− Range: 0.00 to 655.35money = 20.50;money += 5; //adds 5.00money += value;printf(“%w”, money);


RAM AllocationRAM is allocated first come, first served in this order:1. globals2. static3. localCall tree determines which RAM can be reusedUser can force RAM placementStructure/Array cannot be larger than bank


‘const’ vs. ‘rom’‘const’ has two modes:− #device CONST=ROM DEFAULT− #device CONST=READ_ONLY

‘const’ is always read-only‘rom’ places variable in ROM‘rom’ writable if supported by PIC® MCUExamples− const int lookup[16]={0...15};− const char string[]=“Hello”;− rom char *cptr = “Hello”;


Borrowed from C++Reference Parameters

Pass address, not value− More Efficient for large structures− Values can be changed in functionDeclare reference parameters with &

void Inc(int &i) {i++;

}

Many times compiler will inline


Borrowed from C++Default Parameters

Default value passed to function if no value specifiedint1 Get(char *c, int time=200);

Get(&c);− time will be 200

Get(&c, 500);− time will be 500


Borrowed from C++Function Overloading

Multiple functions, same nameDifferent parametersExample:Three different functions called Inc− int Inc(int *i);− long Inc(long *l);− float Inc(float *f);


In-Line Assembly#asm − Starts an assembly block

#endasm − Ends an assembly block

_return_− Assign return value− May be corrupted by any C code

after #endasmSupports all opcodesC variables can be accessedAutomatic banking− #asm ASIS - disables auto-

banking

int find_parity (int data){

int count;#asm

movlw 0x8movwf countmovlw 0

loop:xorwf data,wrrf data,fdecfsz count,fgoto loopmovlw 1addwf count,fmovwf _return_

#endasm}


Output Files

HEX – Compiled ApplicationCOF – Debug ApplicationERR – Compile output messagesLST – C to Assembly comparisonSYM – Memory MapSTA – StatisticsTRE – Call Tree

Programming Details

Required Setup


Pre-processor

Design Goal: All in front of you− Everything is in the source code− No linker scriptsPre-processor commands change compiler-behaviour:− Methodology− ROM/RAM placement− Library configuration


#deviceLoads personality for the target PIC®MCU− #device PIC18F4520Can be used to alter low-level specifics− #device ICD=TRUEPIC MCU header files have #deviceIf creating multiple compilation units (linking), must be defined in each file. − Put it in a common include file


#fuses

Define the configuration bits− #fuses HS, NOWDT, NOLVPTo get list of valid fuses:− In IDE, use View Valid Fuses window− Header file for the device has listTo get a description of each fuse:− In IDE, use View Valid Fuses window− fuses.txt


#use delayConfigure the built-in libraries for the clock speed for your target− #use delay(clock=value)

value is system clock speed, after PLLOnly needed if using the following:− Serial− Delay

For multiple clock speed applications, you can define this more than once

Programming Details

Memory Placement


#byte / #word

Force location of RAMint val;#byte val=0xA0

Overlaying variable onto SFR:#byte STATUS=0x03#word TMR1=0x0E

Repeat, but using getenv():#byte STATUS=getenv(“SFR:STATUS”)


#bit

#bit ident=X.b− Declares boolean at address X, bit b− Examples:

#bit CARRY=STATUS.0#bit CARRY=getenv(“BIT:C”)

Don’t forget:− Compiler will pack ‘int1’ variables− You can use ‘struct’ to pack bits


#orgFix placement in ROM#org start, end− Place following function/constant in

specified program memory

#org 0x400,0x4FFSomeFunction() { /*code*/ }

#org 0x500, 0x5FFconst someStruct[] = { … }

Hands On Lab #2

Debugging a Calculator Application


Lab 2 Objectives

Learn basic debugging use− Breakpoints− Watches− ROM and RAM view− Peripheral StatusLearn advanced debugging use− Logging− 1Wire RS232 on RB3


Lab 2: CCS IDE DebuggerStep 1 – Close All Open Files


Lab 2: CCS IDE DebuggerStep 2 – Load Example Code

Load Example Code− File->Open− C:\masters\1222\Lab2\lab2.c


Lab 2: CCS IDE DebuggerStep 3 – Start Debugger

Start Debugger− Debug -> Enable Debugger


Lab 2: CCS IDE DebuggerDebugger GUI Overview


Lab 2: CCS IDE DebuggerStep 4 – Load Target Code

Compile Project− Compile -> Compile− Project will be loadedPress GO


Lab 2: CCS IDE DebuggerStep 5 – 1-Wire RS232

#use rs232(debugger) − 1-Wire RS232 using RB3− 1-Wire Monitor in Debugger:


Lab 2: CCS IDE DebuggerStep 6 – 1-Wire RS232

Using the Monitor, experiment with the applicationApplication is a simple calculator


Lab 2: CCS IDE DebuggerStep 7 – Breakpoints

Press STOPAdd a Breakpoint to line 63− printf(“\r\nThe result is %lu”, result)− Put cursor on Line 63, Press + on

Break Tab


Lab 2: CCS IDE DebuggerStep 8 – Watching

Open Watch Tab, Press +


Lab 2: CCS IDE DebuggerStep 9 – Watch Dialog

Enter ‘result’ into Expression FieldPress Add Watch


Lab 2: CCS IDE DebuggerStep 10 – Break Logging

Logs an expression at breakpoint− Breakpoint doesn’t stop executionEnter result into Break Log

Press GO

BREAK TIME!

Programming Detailsaddressmod


Pop Quiz

You need to store 128 values but your PIC® MCU only

has 80 bytes of RAM.

What do you do?


addressmod

Application defined storage− What is ‘normal’ storage?typemod, on steroids!Can be used on any data type− Pointers, structs, unions and arrays− ‘const’ and ’rom’ not allowedISO/IEC TR 18037 (Embedded C)


addressmod Syntaxaddressmod(identifier,[read,write,]start,end)− identifier is the new qualifier − read(int32 addr, int8 *ptr, int8 len)− write(int32 addr, int8 *ptr, int8 len)

The IO method to access this memoryOptional

− start/end are the memory range


addressmod Declarationaddressmod(nv, read_nv, write_nv,

0, NV_SIZE);

void read_nv(int32 addr, int8 *ram, int8 n)

{ /* read n from addr */ }

void write_nv(int32 addr, int8 *ram, int8 n)

{ /* write n from ram */ }


addressmod Usage

nv NVBuffer[8192];nv NVID;nv *NVPtr;

#locate NVID=0

NVBuffer[i]=55;*NVPtr++ = 0;


addressmod Ideas

External RAM / FlashCharacter/Grahic LCD access thru a multi-dimensional arrayDebug/trap critical variables

Programming Details

Interrupts


Pop Quiz

What does your ISR need to do?


Interrupt Service Routine

CCS C provides an ISR− Saves status and scratch registers− Checks enable/flags, goes to user

ISR function for that flag− Clears interrupt flag (if needed)− Restores status/scratch registers


Interrupt Service Routine API

enable_interrupts(INT_*) − enable_interrupts(GLOBAL)− enable_interrupts(INT_TIMER0)disable_interrupts(INT_*) clear_interrupt(INT_*) interrupt_active(INT_*)


Interrupt Service Routine API

#int_*− The following function will be processed

for that interrupt

#int_timer0void isr_timer0(void){//HANDLE TIMER0 OVERFLOW

}


Interrupt Service RoutineSpecial Identifiers

#int_global− Function overrides CCS ISR − User must save and restore all

registers altered by their ISR (W, STATUS, scratch used by compiler, etc.)

#int_default− Traps unknown interrupt


Interrupt Service RoutineOptions

These keywords may follow #int_*:− high – (PIC18) Interrupt is high priority− fast – (PIC18) Same as high, but no save− fast – (PCD) Uses shadow registers− level=(0..7) – (PCD) sets interrupt level − noclear – ISR will not clear interrupt flags#device HIGH_INTS=TRUE− Must set to use high/fast ISR on PIC18

Lab #3

Interrupts


Lab 3: ObjectivesLearn how to use the CCS ISRLearn how the CCS built-in functions control the Timer0 and GPIOImplement a stop watch that measures button press time.Open C:\masters\1222\Lab3\lab3.c− Complete the lines marked TODO


Lab 3 HintsHandout has help and finished exampleTIPS:− Press F1 to get compiler help manual− #int_timer0

Following function is called on a Timer 0 overflow− setup_timer_0(RTCC_DIV_256)

Configures Timer 0 to use a divide by 256 prescalar − enable_interrupts(int_xxx)

INT_TIMER0 – Enable Timer 0 InterruptGLOBAL – Enables Global Interrupt

− input(PIN_XX)Returns TRUE if PIN_XX is high, else returns FALSEButton is RA4, or PIN_A4 in CCS

Bored? Try the “Extra Credit”

Programming Details

Built-In Functions


Built-In Functions

Compiler provides functions to:− Control Peripherals (A/D, Serial, etc)− Perform logic optimized to PICInternal to compiler, not linkedSimplify PIC® MCU to PIC MCU migrationFollow any errata workarounds


Easy PIC® MCU Migration#if defined(__PIC18__)

#include <18F4520.h>#elif defined(__PIC14__)

#include <16F877A.h>#endif

#fuses HS, NOWDT, NOLVP#use delay(clock=20000000)

Void main(void) {while(TRUE) {

output_toggle(PIN_C0);delay_ms(500);

}}


getenv()Assists in making portable codeReturns chip information− Program Memory Size− Bulk Erase Size− Configuration Bits SetOptions can be conditionally compiled:#if getenv(“ADC_CHANNELS”) > 0

setup_adc_ports(NO_ANALOGS);#endif


Device Database and Editor


Don’t forget Drivers and Examples!

Drivers provided for complex features or external peripherals− EEPROMs, LCDs, USB, FAT, etc

Many example programs provided to showcase built-in functions/driversAlways kept up to date with latest peripheralsBefore you start a project, examine the libraries and example programs CCS provides you to reduce your development time


Built-In FunctionsGeneral Purpose Input / Output

output_high(PIN_XX)output_low(PIN_XX)− Sets the pin to desired level− PIN_XX (ex PIN_C0, PIN_B5, etc) are

defined in the device header fileoutput_toggle(PIN_XX)− Toggle high/low state of the pinbool=input(PIN_XX)− Read value of pin



output_X(value)− Sets the port X (A to J) to the desired

valuebyte=input_X()− Read value of port Xset_tris_X(value)val = get_tris_X()− Get/Set the tristate setting



#use standard_io(X)− Output functions set TRIS to output− Input functions set TRIS to input− This is the default operation#use fast_io(X)− Compiler does not alter TRIS#use fixed_io(port_outputs=pins)− #use fixed_io(d_outputs=PIN_D7)


Built-In FunctionsBit Manipulation

bool=bit_test(var, bit)− Returns the value of the specified bitbit_clear(var, bit)bit_set(var, bit)− Set/clear the specified bitThe above bit_XXX() functions use the PIC® MCU’s bit operation opcodes for maximum efficiency


Built-In FunctionsDelays

delay_cycles(x)delay_us(x)delay_ms(x)− Uses a series of loops and NOPs− Timing based on #use delay()− Multiple #use delay() allowed


#use delay(clock=125000)

//1 second delay @ 125kHzvoid Delay1s125khz(void) {delay_ms(1000);

}

#use delay(clock=8000000)

//1 second delay @ 8MHzVoid Delay1s8Mhz(void) { delay_ms(1000);

}

Built-In Functions

Serial Libraries


Pop Quiz

You need to add another serial port to your project,

but you have used all of the PIC® MCU’s peripherals.

What do you do?


UART

Powerful UART library built into compiler#use rs232(baud=xxxx, xmit=PIN_XX,

rcv=PIN_XX, stream=yyyyy)− TX/RX pins can be any pins− Many more options exist

Enable bit, parity, collision detection, open-collector mode, etc.

− Timing is based on #use delay()


UART (Continued)Standard C I/O, last #use rs232()− printf(“string”, …)− char=getc()− putc(char)

Standard C I/O, streams:− fprintf(stream, “string”, …)− char=fgetc(stream)− putc(char, stream)

bool=kbhit(stream)setup_uart(newBaud, stream)− Dynamically change the UART


Dual UART Example#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7,

stream=HW_UART)

#use rs232(baud=9600, xmit=PIN_D0, rcv=PIN_B0, stream=SW_UART, disable_ints)

fprintf(HW_UART, “HELLO HARDWARE UART\r\n”);

fprintf(SW_UART, “HELLO SOFTWARE UART\r\n”);

if (kbhit(HW_UART)) {c=fgetc(HW_UART);fputc(c,SW_UART);

}if (kbhit(SW_UART)) {

c=fgetc(SW_UART);fputc(c,HW_UART);

}


printf() Redirection

printf() can be redirected to a user-defined functionExample:void LCDPut(char c);printf(LCDPut, “%U”, val);


I2C™ LibraryMultiple I2C channels on any I/O pins#use i2c(master, sda=pin_XX,

scl=pin_XX, address=YY, stream=id)

− The SDA and SCL pins can be any pins− Slave Mode is HW MSSP only− Address Is only needed in slave mode


I2C™ Library (Continued)

i2c_start()− Can also be used to send a re-start signalchar=i2c_read(ack)− Ack is an optional parameterack = i2c_write(char)bool=i2c_available()− Can only be used with a hardware MSSPi2c_stop()


SPI

Configurable SPI library#use spi(parameters)− HW or SW pins− Multiple streams− Clock rate and clock mode

configurablein = spi_xfer(STREAM_SPI, out)

Built-in Functions

A/D Converter


A/D Converter

setup_adc(mode)− Configure and the ADC; mode varies

for each typesetup_adc_ports(config)− Configure the pins for analog or

digital mode#device ADC=X− Assign the ADC result size


A/D Converter (Continued)

set_adc_channel(channel)− Set the channel for subsequent readsval = read_adc(mode)− ADC_START_ONLY – Start a conversion− ADC_READ_ONLY – Read last

conversion− ADC_START_AND_READ – Full cycleadc_done()− Returns TRUE if conversion is done


A/D Converter Example//INIT#device ADC=10setup_adc(ADC_CLOCK_INTERNAL );setup_adc_ports(AN0);

//APPLICATIONint16 result;set_adc_channel(0);read_adc(ADC_START_ONLY);

/* do something while A/D is busy */while (!adc_done());result=read_adc(ADC_READ_ONLY);


Getting Help

So many peripherals, how do I get help?

1. In PCW, Press F1 for context sensitive help

2. Look for section labeled ‘Functional Overviews’

Lab #4

Analog to Digital Conversion


Lab 4

Read A/D conversionConvert A/D result to 0 to 5 using floatLight LEDs based upon voltageC:\masters\1222\Lab4\lab4.c− Complete the lines marked TODO


Lab 4 HintsC:\masters\1222\Lab4\lab4.c− Complete the lines marked TODOHandout has help, finished exampleADC Troubles?− Did you enable A/D with setup_adc()?− Did you set the channel?− Is A/D correct, but fixed() math wrong?

Verify readings using debuggerBored? Try “Extra Credit”

Class Summary


Class Summary

Leaving this class you should:− Be able to use your C knowledge and

write applications using CCS C− Know how to use the CCS software to

load your code onto a PIC® MCU and debug it

− Know the ways the CCS C Compiler speeds up development time with built-in functions, drivers, example files and context sensitive help

Thank You!

Please fill out evaluation form.

AppendixFrequently Asked

Questions


Why do I get out of ROM error, when there is ROM left?

A function must fit into one bankOn 14-bit this is 2KSplit large functions, and main(), into several smaller functions− This is good programming practice

any way!


How Can I Reduce Code Space?

Use int1 or bit fields for flagsUse fixed point decimal, not floatDivide large functionsAvoid ->, move structure to localUse access bank mode− #device *=8− read_bank(b,o), write_bank(b,o,v)


Why is My Math Clipped at 8-bits?

Examine the following code:− val16=val8 * val16;The optimizer will use the smallest data type for math, in this case int8Typecasting forces math into proper mode:− val16=(int16) val8 * val16;

AppendixProgramming Details

Miscellaneous


addressmod Block

#type default=qualifier− Following declarations will use this

qualifier− If qualifier blank, goes back to default

#type default=nv

char buffer[8192];#include <memoryhog.h>

#type default=


Pre-Processor Miscellaneous

__pcb____pcm____pch____pcd__− Returns the version of specified compiler

__date____time__− Time/Date project was compiled

#id CHECKSUM#id value− Place this value (or checksum) into ID location


Bit Arrays

Array of bits:− int1 flags[30]={FALSE};− flags[i] = TRUE;− if (flags[10]) { /* some code */ }Bits are packedPointers not supported


String ParametersString can be function parameterLCDPuts(“Hello”);Example (RAM):

#device PASS_STRINGS=IN_RAMvoid LCDPuts(char *str);

Example (Const RAM):#device PASS_STRINGS=IN_RAM#device CONST=ROMvoid LCDPuts(const char *str);

Example (ROM):void LCDPuts(rom char *str);


#importImport various files into project.#import(File=name, Type)Type = Relocatable (.o, .cof)− ‘only’ and ‘except’ specifies what C

symbolsType = HEX (.hex)− ‘range’ parameter specifies rangeType = RAW− ‘location’ gets or sets location− ‘size’ parameter gets size

Appendix

Output Files


Output Files

HEX – Compiled ApplicationCOF – Debug ApplicationERR – Compile output messagesLST – C to Assembly comparisonSYM – Memory MapSTA – StatisticsTRE – Call Tree


SYM – Memory Map

First section is RAM memory map005-014 main.bufferna main.index‘na’ indicates no RAMFollowing sections include:− Other Input files− ROM memory map− PIC® MCU / Compiler Settings


STA Statistics

Review ROM/RAM/Stack used.Statistics for each function:

Page ROM % RAM Functions:---- --- --- --- ----------0 26 0 1 @delay_ms10 284 1 3 ee_reset


STA Statistics

Statistics for each segment:Segment Used Free--------- ----- ----00000-00006 4 4 00008-000B2 172 0 000B4-03FFE 15826 378


TRE Statistics

Review call tree− Function Name - Segment/ROM – RAM

projectmain 0/84 Ram=0init 0/194 Ram=1

RELAY_INIT 0/16 Ram=0RELAY1_OFF (Inline) Ram=0@delay_ms1 0/26 Ram=1

Segment will be ? if it won’t fit


Out of ROMFull output:Out of ROM, A segment or the program is too large: XXXXXXSeg w-x, y left, need zSeg 0-3ff, 12C left, need 12F

Tips:− Be aware of processor segment size

Seg 0-3FF, 3FF left, need 412− Optimize code− Split large functions− Reduce stack usage (allows more CALLs)


How Can I Reduce Code Space?

Use int1 or bit fields for flagsUse fixed point decimal, not floatDivide large functionsAvoid ->, move structure to localUse access bank mode− #device *=8− read_bank(b,o), write_bank(b,o,v)


Out of RAM

Full error message:Not enough RAM for all variablesReview SYM fileTips:− Be aware of PIC® MCU bank size− Use bit flags− Use local variables (not global)

AppendixOther Built-In Functions


Internal Data EEPROM

Access internal data EEPROMv = read_eeprom(address)write_eeprom(address, v)


Read / Write Program Memory

Treat program memory like data EEPROMv=read_program_eeprom(a)write_program_eeprom(a, v)− Size of v depends on architectureread_program_memory(a, ptr, num)write_program_memory(a, ptr, num)erase_program_memory(a)


Built-In FunctionsByte Manipulation

int8=make8(variable, offset)− Returns one byte from variableint16=make16(i8MSB, i8LSB)int32=make32(iMSB..iLSB)− Returns the combined valueswap(value)− Swaps nibble, saves to value


Timerssetup_timer_X(mode)− Mode contains configuration info, such as

prescalar, postscalar, period, etc.− setup_timer_1(T1_INTERNAL | T1_DIV_BY_4);

set_timerX(new_count)current_count=get_timerX()− Set/Get Timer count− Word Safe


Capture / Compare / PWM

setup_ccpX(mode)− Mode contains configuration,

examine header for full options− setup_ccp1(CCP_PWM)

set_pwmX_duty(new_duty)− % = new_duty / (4 * period)


Peripheral ControlParallel Slave Port

setup_psp(mode)− Mode is PSP_ENABLED or

PSP_DISABLEDfull=psp_output_full()avail=psp_input_full()isOverflowed=psp_overflow()psp_data− A variable mapped to the PSP I/O port


Built-In FunctionsMiscellaneous

ext_int_edge(which, mode)− ext_int_edge(0, H_TO_L)port_X_pullups(boolean)setup_oscillator(mode, finetune)− finetune is optional− setup_oscillator(OSC_2MHZ)

Appendix

Fixed Memory Placement


#rom

Place raw data into program memory#rom address={data….data}Application Ideas:− Initialize the internal data EEPROM− Manually set configuration bits− Manually set ID location− Place strings into ROM


#inline and #separate#inline− Makes following function inline− Best if used with reference parameters#separate− Makes following function separate (called)Generally you should let the optimizer determine if a function should be separate or inline


#locateForce location of variable#locate ident=X− Assigns the C variable ident to location X− X can be a literal, or variable identifier− If not specified, ident is treated as a byte− Compiler allocates X− Can be any structure or type (not const)


#locate examples

Overlaying variable onto SFR:#locate STATUS=5

Repeat, but using get_env():#locate STATUS=get_env(“SFR:STATUS”)

Overlaying two variables:char buffer[512];

struct { /*protocol */} header;#locate header=buffer+2


#byte and #bit

#byte ident=X− Same as #locate, but no allocation#bit ident=X.b− Declares boolean at address X, bit b− Examples:

#bit CARRY=STATUS.0#bit CARRY=get_env(“BIT:C”)


#rom

Place raw data into program memory#rom address={data….data}Application Ideas:− Place strings into ROM− Initialize the internal data EEPROM− Manually set configuration bits− Manually set ID location


#inline and #separate#inline− Makes following function inline#separate− Makes following function separate (called)− Disables stack overflow checkGenerally you should let the optimizer determine if a function should be separate or inline


#org

Create segment, force code into segment.#org start, end− Place following function/constant in

this segment#org start− Continue previous segment


#org ExampleForce following code into 0x100-0x1FF

#org 0x100, 0x1FFvoid func1(void) {/*code*/}

#org 0x100const cstring[]=“Hello”;

#org 0x100void func2(void) {/*code*/}

//Valid Protoype#seperate void func1(void);


#org

#org start, end DEFAULT− Forces all following

function/constants into this segment#org DEFAULT− Terminate previous DEFAULT#org start, end { }− Reserve ROM


#org Example 2Force following code into 0x100-0x1FF

#org 0x100, 0x1FF defaultvoid func1(void) {/*code*/}

const cstring[]=“Hello”;

void func2(void) {/*code*/}

#org default


#org

View .STA to view current segment usage:

Segment Used Free0000-0003: 4 00004-00FF: 250 20100-01FF: 190 660200-07FF: 1337 199


#buildCan change reset and interrupt segment#build(segment=start:end)Valid segments:− reset – the location of the reset vector− interrupt – the location of the interrupt vector− memory – external memory for CPU mode

Examples:− #build(reset=0x800, interrupt=0x808)− #build(memory=0x10000:0x1FFFF)

Appendix

Bootloader Example


Bootloader Overview

Two programs:− Loader− ApplicationEach program #org’dto their own space− Loader in low memory

(0-7FF)− Application high

memory (800-end)


Bootloader/Application Common Code

#define BOOT_END (0x7FF)

#define APP_START (BOOT_END+1)

#define APP_ISR (APP_START+8)

#define PROGRAM_END

getenv(“PROGRAM_MEMORY”)


Bootloader ExampleLoader Code

//prevent bootloader from using application#org APP_START , PROGRAM_END { }

#int_globalvoid isr(void) {

//goto interrupt in applicationjump_to_isr(APP_ISR);

}

void main(void) {if (IsBootloadEvent())

Bootload();#asmgoto APP_START#endasm

}


Bootloader ExampleApplication Code

#import(file=loader.hex, range=0:BOOT_END)

#build(reset=APP_START,interrupt=APP_ISR)

#org 0,BOOT_END { }

#int_timer0void timer(void) { /* do timer0 isr */ }

Void main(void) {/* code */

}

Appendix

RTOS


RTOS Basics

Multitasking thru time-sharing− Tasks appear to run at same time‘Real Time’Task is in one of three states:− Running− Ready− Blocked


The CCS RTOS

Cooperative Multitasking Tightly integrated with compilerSupports ALL PIC® MCUs with a TimerAvailable to IDE customers


RTOS Setup

#use rtos(timer=X, [minor_cycle=cycle_time])− Timer can be any timer available− Minor_Cycle is rate of fastest task− Example:#use rtos(timer=1, minor_cycle=50ms)


RTOS Tasks

#task(rate=xxxx, [max=yyyy], [queue=z])− Following function is RTOS task− Will be called at specified rate− Max is slowest execution time, used

for budgeting− Queue defines RX message size


RTOS Start and Stop

rtos_run()− Starts the RTOS− Will not return until rtos_terminate()rtos_terminate()− Stops the RTOS


#use rtos(timer=1)

#task(rate=100ms, max=5ms)void TaskInput(void){ /* get user input */ }

#task(rate=25ms)void TaskSystem(void){ /* do some stuff */ }


RTOS Task Control

rtos_enable(task)rtos_disable(task)− Dynamic task control− Enable/Disable the specified task− Task is the function name− All tasks are enabled at start


RTOS Messaging

rtos_msg_send(task, char)− Sends char to taskavail=rtos_msg_poll()− TRUE if a char is waiting for this taskbyte=rtos_msg_read()− Read next char destined for this task


RTOS Yielding

rtos_yield()− Stops processing current task− Returns to this point on next cyclertos_await(expression)− rtos_yield() if expression not TRUE


#task(rate=100ms, max=5ms)void TaskInput(void) {if (KeyReady())rtos_msg_send(TaskSystem,

KeyGet());}

#task(rate=25ms, queue=1)void TaskSystem(void) {


RTOS SemaphoresSemaphore− Determine shared resource availability − A user defined global variable− Set to non-zero if used− Set to zero if freertos_wait(semaphore)− rtos_yield() until semaphore free− Once free, sets semaphore as usedrtos_signal(semaphore)− Release semaphore


RTOS Timing Statisticsoverrun=rtos_overrun(task)− TRUE if task took longer than maxrtos_stats(task, rtos_stats)− Get timing statistics for specified task

typedef struct {int32 total; // total ticks used by taskint16 min; // minimum tick time usedint16 max; // maximum tick time usedint16 hns; // us = (ticks*hns)/10

} rtos_stats;


RTOS Application Ideas

User I/OCommunication Protocols


TrademarksThe Microchip name and logo, the Microchip logo, Accuron, dsPIC, KeeLoq, KeeLoq logo, MPLAB, PIC, PICmicro, PICSTART, PRO MATE, rfPIC and SmartShunt are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries.FilterLab, Linear Active Thermistor, MXDEV, MXLAB, SEEVAL, SmartSensorand The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A.Analog-for-the-Digital Age, Application Maestro, CodeGuard, dsPICDEM, dsPICDEM.net, dsPICworks, dsSPEAK, ECAN, ECONOMONITOR, FanSense, In-Circuit Serial Programming, ICSP, ICEPIC, Mindi, MiWi, MPASM, MPLAB Certified logo, MPLIB, MPLINK, mTouch, PICkit, PICDEM, PICDEM.net, PICtail, PIC32 logo, PowerCal, PowerInfo, PowerMate, PowerTool, REAL ICE, rfLAB, Select Mode, Total Endurance, UNI/O, WiperLock 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.All other trademarks mentioned herein are property of their respective companies.© 2008, Microchip Technology Incorporated. All Rights Reserved.

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