University of Plymouth - Stages 1, 2 and 3
/
Task523Solution
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main.cpp@3:134bd19c5f04, 2019-09-20 (annotated)
- Committer:
- noutram
- Date:
- Fri Sep 20 13:39:27 2019 +0000
- Revision:
- 3:134bd19c5f04
- Parent:
- 2:df9c87ac7704
2019
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| noutram | 0:277f12eec770 | 1 | #include "mbed.h" |
| noutram | 0:277f12eec770 | 2 | |
| noutram | 0:277f12eec770 | 3 | //Global PWM object |
| noutram | 3:134bd19c5f04 | 4 | #ifdef TARGET_NUCLEO_F429ZI |
| noutram | 3:134bd19c5f04 | 5 | PwmOut pwmRed(D6); //D7 is not a PWM output on the F429, so use D6 instead |
| noutram | 3:134bd19c5f04 | 6 | #else |
| noutram | 3:134bd19c5f04 | 7 | PwmOut pwmRed(D7); |
| noutram | 3:134bd19c5f04 | 8 | #endif |
| noutram | 0:277f12eec770 | 9 | |
| noutram | 0:277f12eec770 | 10 | int T = 100; //100uS |
| noutram | 0:277f12eec770 | 11 | volatile int Tmark = 0; //0us |
| noutram | 0:277f12eec770 | 12 | volatile int delta = 1; //1us |
| noutram | 0:277f12eec770 | 13 | |
| noutram | 0:277f12eec770 | 14 | //Timer |
| noutram | 0:277f12eec770 | 15 | Ticker t; |
| noutram | 0:277f12eec770 | 16 | |
| noutram | 0:277f12eec770 | 17 | //Function prototype |
| noutram | 0:277f12eec770 | 18 | void doTwinkle(); |
| noutram | 0:277f12eec770 | 19 | |
| noutram | 0:277f12eec770 | 20 | int main() { |
| noutram | 0:277f12eec770 | 21 | |
| noutram | 0:277f12eec770 | 22 | //Initial PWM state |
| noutram | 0:277f12eec770 | 23 | pwmRed.period_us(T); |
| noutram | 0:277f12eec770 | 24 | pwmRed.pulsewidth_us(Tmark); |
| noutram | 0:277f12eec770 | 25 | |
| noutram | 0:277f12eec770 | 26 | //Start timer |
| noutram | 0:277f12eec770 | 27 | t.attach(doTwinkle, 0.01); |
| noutram | 0:277f12eec770 | 28 | |
| noutram | 0:277f12eec770 | 29 | while(1) { |
| noutram | 0:277f12eec770 | 30 | sleep(); |
| noutram | 0:277f12eec770 | 31 | |
| noutram | 0:277f12eec770 | 32 | //Update PWM |
| noutram | 0:277f12eec770 | 33 | pwmRed.pulsewidth_us(Tmark); |
| noutram | 0:277f12eec770 | 34 | |
| noutram | 0:277f12eec770 | 35 | //printf("Tmark = %d\n", Tmark); //Debug |
| noutram | 0:277f12eec770 | 36 | } |
| noutram | 0:277f12eec770 | 37 | } |
| noutram | 0:277f12eec770 | 38 | |
| noutram | 0:277f12eec770 | 39 | //ISR for Timer |
| noutram | 0:277f12eec770 | 40 | void doTwinkle() |
| noutram | 0:277f12eec770 | 41 | { |
| noutram | 0:277f12eec770 | 42 | //Update mark time |
| noutram | 0:277f12eec770 | 43 | Tmark += delta; |
| noutram | 0:277f12eec770 | 44 | |
| noutram | 0:277f12eec770 | 45 | //Check bounds - and swap direction |
| noutram | 0:277f12eec770 | 46 | if ((Tmark >= 99) || (Tmark <= 0)) { |
| noutram | 0:277f12eec770 | 47 | delta = -delta; |
| noutram | 0:277f12eec770 | 48 | } |
| noutram | 0:277f12eec770 | 49 | } |