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Embedded Software Assignment 2
Dependencies: MCP23017 WattBob_TextLCD mbed
main.cpp
- Committer:
- usmb192
- Date:
- 2016-05-27
- Revision:
- 0:0131c822a391
File content as of revision 0:0131c822a391:
/*******************************************************************************************
*
* Cyclic Execution based Frequency Measurement ( Embedded Software Assignment 2 )
*
* a program that runs a cyclic execution demo
* actions are for example
* frequency measurement and serial logging
*
*
* @author Markus
* @version 1.0
* @lastupdate 02.03.2016
*
*
*******************************************************************************************/
// ########
// INCLUDES
// ########
#include "mbed.h" // mbed header file
#include "MCP23017.h" // include 16-bit parallel I/O header file
#include "WattBob_TextLCD.h" // include 2*16 character display header file
#include "AnalogIn.h" // include Analog communication
#include <deque> // used for the avaraging
// #######################
// CONFIGURATION VARIABLES
// #######################
#define SAMPLE_FREQ_US 1
#define TICKRATE_US 12500
#define NYQUIST_CORR 2.002
#define WATCHDOG_PULSE_TIME_MS 5
// ###############################
// ALL PORTS USED ARE DEFINED HERE
// ###############################
#define AnalogPort1 p17 // used for Analog Input 1
#define AnalogPort2 p16 // used for Analog Input 2
#define FrequencyPort p15 // used to measure frequency
#define SwitchPort p5 // used for the error code switch
#define WatchPort p6 // used for the watchdog pulse
#define OnOffPort p7 // used for the on/off switch
#define TaskExecPort p8 // used for the task execution pulse
// ####################################
// MISC VARIABLES (shouln't be changed)
// ####################################
MCP23017 *par_port; // pointer to 16-bit parallel I/O object
WattBob_TextLCD *lcd; // pointer to 2*16 chacater LCD object
Serial serpc(USBTX, USBRX); // serial usb connection tx, rx
Ticker ticker; // our ticker that runs the main function
DigitalIn dInFreq(FrequencyPort); // Port for the frequency measurement
DigitalIn dInSwitch(SwitchPort); // Port for the switch
DigitalOut dOutWatchd(WatchPort); // Port for WatchDog pulse
DigitalIn dInOnOff(OnOffPort); // Port for the On/Off Switch
DigitalOut dOutTaskExec(TaskExecPort);
std::deque<float> AnalogDB1;
std::deque<float> AnalogDB2;
int tick_counter(0); // used for counting the ticks / slots
bool OnOffSwitchStatus(0); // saving the last switch status
int freq(0); // saving the last frequency status
int error_last(9); // we init with an impossible error number only 0 and 3 are
// possible, using this we force an initialization
float avgAn1(0); // saving the last avarage of analog 1
float avgAn2(0); // saving the last avarage of analog 2
bool Switch1(0); // saving the last switch status
DigitalOut ledd1(LED1);
DigitalOut ledd3(LED3);
// ################################
// FORWARD DECLARATION OF FUNCTIONS
// ################################
void SendPulse(int ms, DigitalOut pn);
void tick();
void printLCD(int& freq,bool& sw, float& avgAn1, float& avgAn2);
void logTime(int TaskNumber);
int MeasureFrequency(DigitalIn& freqIn,int samplingFreqUS);
float ReadAnalogInAVG(std::deque<float>& db,PinName Port);
int CheckError(bool& Switch1,float& avgAn1,float& avgAn2);
/*
========================================================================================
= =
= MAIN PROCEDURE - generating the Blocks =
= =
========================================================================================
*/
// ############################
// the entrance for the program
// ############################
int main()
{
serpc.baud(19200); // setup the bautrate
serpc.printf("Init Software\r\n");
par_port = new MCP23017(p9, p10, 0x40); // initialise 16-bit I/O chip (0x40 = 64)
lcd = new WattBob_TextLCD(par_port); // initialise 2*26 char display
par_port->write_bit(1,BL_BIT); // turn LCD backlight ON
lcd->cls(); // clear display
lcd->locate(0,0); // set cursor to location (0,0) - top left corner
lcd->printf("f0000 S0"); // print labels on the lcd
lcd->locate(1,0);
lcd->printf("a1 0.00 a2 0.00");
ticker.attach_us(&tick, TICKRATE_US); // attach the ticker to a procedure
}
// #########################
// the main loop (as ticker)
// #########################
void tick()
{
// use a timing pulse -> extra digi port -> everytime something happens -> sent pulse
// tickcounter%interval==offset
if((tick_counter%80)==1) {
//every 1000 mS
freq = MeasureFrequency(dInFreq,SAMPLE_FREQ_US); // measure the frequency
} else if((tick_counter%24)==2) {
//every 300 mS, check Switch1 (for error)
if (dInSwitch) // check the switch status for later use
Switch1 = true;
else Switch1 = false;
} else if((tick_counter%24)==3) {
// (460 mS) now 300 mS, send watchdog pulse
SendPulse(WATCHDOG_PULSE_TIME_MS,dOutWatchd); // send the watchdog pulse
} else if((tick_counter%32)==4) {
// every 400 mS
// EXECUTION SIGNAL!
SendPulse(10,dOutTaskExec); // sending the execution signal
avgAn1 = ReadAnalogInAVG(AnalogDB1,AnalogPort1); // reaning analog values
avgAn2 = ReadAnalogInAVG(AnalogDB2,AnalogPort2); // ^^
} else if((tick_counter%160)==5) {
// every 2000 Ms
printLCD(freq,Switch1,avgAn1,avgAn2); // print to the lcd screen
} else if((tick_counter%64)==8) {
// every 800 mS
int error_current = CheckError(Switch1,avgAn1,avgAn2);
if (error_last!=error_current) { // we check if the error changed (safe to time )
if(!error_current) { // we check if its zero
ledd1=1;
ledd3=0;
} else { // else it must be 3
ledd1=0;
ledd3=1;
}
error_last=error_current;
}
} else if((tick_counter%400)==9) {
// every 5000 mS - print to serial
serpc.printf("%i,%i%,%i,%i\r\n",freq,Switch1,(int)avgAn1,(int)avgAn2);
} else {
// in every other slot, check the on off switch
if(OnOffSwitchStatus!=dInOnOff) { // checking the on off switch
OnOffSwitchStatus = dInOnOff; // safe the last switch status
par_port->write_bit(OnOffSwitchStatus,BL_BIT); // turn LCD backlight ON/OFF
}
}
tick_counter++;
}
/*
========================================================================================
= =
= FUNCTIONS BLOCK =
= =
========================================================================================
*/
// #########################################################################################
// prints to the lcd, only overwrites values that are necesarry to overwrite (safes some mS)
// #########################################################################################
void printLCD(int& freq,bool& sw, float& avgAn1, float& avgAn2)
{
lcd->locate(0,1);
lcd->printf("%04i",freq); // write the frequency to the lcd board
lcd->locate(0,7);
lcd->printf("%i",sw); // write the switch value
lcd->locate(1,3);
lcd->printf("%.2f",avgAn1); // write avarage analog value 1
lcd->locate(1,12);
lcd->printf("%.2f",avgAn2); // write avarage analog value 2
}
// #################################################
// checks the error status and returns it as integer
// #################################################
int CheckError(bool& Switch1,float& avgAn1,float& avgAn2)
{
if(Switch1 && (avgAn1 > avgAn2)) // if swicht1 AND averageAnalogValue1 > averageAnalogValue2
return 3;
return 0;
}
// ####################################################################
// reads analog values and returns the average over the last 4 readings
// ####################################################################
float ReadAnalogInAVG(std::deque<float>& db,PinName Port) // (we are using deque because you cant iterate over a queue)
{
AnalogIn Ain(Port);
float sum(0);
if(db.size()>=4) // if we already got 4 values, we have to
db.pop_front(); // make space by deleting the oldest value
db.push_back(Ain.read()); // safe a new reading
for(deque<float>::const_iterator i = db.begin(); i != db.end(); ++i)
sum+= *i; // calculate the average by iterating over the queue
return sum/db.size();
}
// ##################################################
// used for sending a short pulse for ms Milliseconds
// ##################################################
void SendPulse(int ms, DigitalOut pn)
{
pn = 1; // set the analog port high
wait_ms(ms); // wait for ms Milliseconds
pn = 0; // set the analog port low
}
// ###################################################
// measures the frequency and returns an integer in Hz
// ###################################################
int MeasureFrequency(DigitalIn& freqIn,int samplingFreqUS)
{
Timer timer; // timer used to time
if(!freqIn) { // if the edge is low
while(!freqIn) // wait for the edge
wait_us(samplingFreqUS); // let the cpu do nothing meanwhile
timer.start(); // now we can start counting
while(freqIn) // as long as the freq is high
wait_us(samplingFreqUS);
} else { // else.. it has to be 1
while(freqIn) // wait for the edge
wait_us(samplingFreqUS); // let the cpu do nothing meanwhile
timer.start(); // now we can start counting
while(!freqIn) // as long as the frequency is slow
wait_us(samplingFreqUS); // let the cpu do nothing
}
timer.stop(); // stop the timer - measuring finished
return 1000000.0/(timer.read_us()*NYQUIST_CORR); // Convert to period multiply by 1mil to get freq and correct by Nequ
}