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Lab 3 ADC
Fork of ADCandticker_sample by
main.cpp
- Committer:
- Bossman
- Date:
- 2018-02-09
- Revision:
- 2:9d5147fbeded
- Parent:
- 1:126dd2f5fc2d
File content as of revision 2:9d5147fbeded:
// LAB 3 SAMPLE PROGRAM 1 // Revised for mbed 5 #include "mbed.h" Ticker tick; // Ticker for reading analog AnalogIn ain(A0) ; // Analog input DigitalOut lede1(PTD0); // Red LED DigitalOut lede2(PTD5) ; DigitalOut lede3(PTD2) ; DigitalOut lede4(PTD3) ; DigitalOut lede5(PTD1) ; //InterruptIn button(PTD4); Serial pc(USBTX, USBRX); // tx, rx, for debugging DigitalIn b1(PTD4, PullUp); Thread pollT ; // thread to poll volatile int pressEvent=0; enum buttonPos { up, down, bounce }; // Button positions // three options of button position void polling() { buttonPos pos = up ;// initial position int bcounter = 0 ; while (true) { switch (pos) { case up : if (!b1.read()) { // now down pressEvent = 1 ; // transition occurred pos = down ; // action and update position } break ; case down : if (b1 == 1) { // no longer down. what the default value of b1?- > it depends and doesnt have initial value bcounter = 3 ; // wait four cycles pos = bounce ; } break ; case bounce : if (b1 == 0) { // down again - button has bounced pos = down ; // no event } else if (bcounter == 0) { pos = up ; // delay passed - reset to up } else { bcounter-- ; // continue waiting } break ; } Thread::wait(30); } } // Message type typedef struct { uint16_t analog; /* Analog input value */ } message_t; // Mail box Mail<message_t, 2> mailbox; // Function called every 10ms to read ADC // Low pass filter // Every 10th value is sent to mailbox volatile int samples = 0 ; volatile uint16_t smoothed = 0 ; void readA0() { smoothed = (smoothed >> 1) + (ain.read_u16() >> 1) ; samples++ ; if (samples == 10) { // send to thread message_t *mess = mailbox.alloc() ; // may fail but does not block if (mess) { mess->analog = smoothed ; mailbox.put(mess); // fails but does not block if full } samples = 0; } } // Write voltage digits // v Voltage as scale int, e.g. 3.30 is 330 void vToString(int v, char* s) { s[3] = '0' + (v % 10) ; v = v / 10 ; s[2] = '0' + (v % 10) ; v = v / 10 ; s[0] = '0' + (v % 10) ; } // Main program // Initialise variables // Attach ISR for ticker // Procss messages from mailbox int main() { //led1 = 1 ; // turn off int volts = 0 ; //const int threshold = 100 ; bool max_volts = false; bool detector = false; int counter = 0 ; int threshold[6] = {55,110,165,220,275,330}; char vstring[] = "X.XX\r\n" ; pollT.start(callback(polling)); tick.attach_us(callback(&readA0), 10000); // ticks every 10ms while (true) { osEvent evt = mailbox.get(); // wait for mail if (pressEvent) { // main event pressEvent = 0 ; // clear the event variable max_volts = !max_volts; detector = false; } if (evt.status == osEventMail) { message_t* mess = (message_t*)evt.value.p ; volts = (mess->analog * 330) / 0xffff ; mailbox.free(mess) ; // free the message space if ((volts<=(threshold[0]))&&(max_volts==false)) { lede1 = 0; lede2 = 0; lede3 = 0; lede4 = 0; lede5 = 0; } else if ((volts<=threshold[1])&&(volts>threshold[0])&&(max_volts==false)) { lede1 = 1; lede2 = 0; lede3 = 0; lede4 = 0; lede5 = 0; } else if ((volts<=threshold[2])&&(volts>threshold[1])&&(max_volts==false)) { lede1 = 1; lede2 = 1; lede3 = 0; lede4 = 0; lede5 = 0; } else if ((volts<=threshold[3])&&(volts>threshold[2])&&(max_volts==false)) { lede1 = 1; lede2 = 1; lede3 = 1; lede4 = 0; lede5 = 0; } else if ((volts<=threshold[4])&&(volts>threshold[3])&&(max_volts==false)) { lede1 = 1; lede2 = 1; lede3 = 1; lede4 = 1; lede5 = 0; } else if (((volts<=threshold[5])&&(volts>threshold[4]))||(max_volts==true)) { lede1 = 1; lede2 = 1; lede3 = 1; lede4 = 1; lede5 = 1; if(volts >= threshold[4]){ max_volts = false; } } vToString(volts, vstring) ; counter++ ; if (counter == 10) { // limit bandwidth of serial pc.printf(vstring) ; counter = 0 ; } } } }