Craig Evans
/
ELEC2645_Ticker_WAV
Plays WAV file
Diff: main.cpp
- Revision:
- 4:a46b7a818e39
- Parent:
- 3:8daf84a849e5
diff -r 8daf84a849e5 -r a46b7a818e39 main.cpp --- a/main.cpp Fri Jan 24 10:50:28 2020 +0000 +++ b/main.cpp Mon Jan 27 14:02:36 2020 +0000 @@ -1,4 +1,4 @@ -/* +/* 2645_Ticker @@ -10,49 +10,54 @@ updated January 2020 - uses Gamepad2 peripherals -*/ +*/ #include "mbed.h" +#include "Gamepad.h" +#include "SoundData.h" // Create objects for ticker and red LED Ticker ticker; -DigitalOut led1(PTA2); +Gamepad pad; // flag - must be volatile as changes within ISR // g_ prefix makes it easier to distinguish it as global volatile int g_timer_flag = 0; +volatile int g_sample = 0; // function prototypes void timer_isr(); int main() { - // set-up the ticker so that the ISR it is called every 0.5 seconds - ticker.attach(&timer_isr,0.5); - - // the LED is common anode - writing a 1 to the pin will turn the LED OFF - led1 = 1; + pad.init(); + // sample rate of music + ticker.attach(&timer_isr,220e-6); while (1) { - // check if flag is set i.e. interrupt has occured - if (g_timer_flag) { - g_timer_flag = 0; // if it has, clear the flag + if (g_timer_flag == 1) { + g_timer_flag = 0; - // send message over serial port - can observe in CoolTerm etc. - printf("Tick \n"); - // DO TASK HERE - - led1 = ! led1; - + // loop if reach end of samples + if (g_sample >= NUM_ELEMENTS) { + g_sample = 0; + } + // convert from 0 to 255 to 0.0 to 1.0 + float val = float(sound_data[g_sample])/ 256.0f; + // write to DAC + pad.write_dac(val); + // move onto next sample + g_sample++; + } // put the MCU to sleep until an interrupt wakes it up sleep(); - } } + // time-triggered interrupt void timer_isr() {