William Marsh / Mbed OS DACandticker_sample_with_debug

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main.cpp@1:284229960d6a, 2018-01-24 (annotated)

Committer:
WilliamMarshQMUL
Date:
Wed Jan 24 22:59:37 2018 +0000
Revision:
1:284229960d6a
Parent:
0:5307f49cd305
Child:
2:4857a7cbb9da
Revised for mbed 5

Who changed what in which revision?

UserRevisionLine numberNew contents of line
WilliamMarshQMUL 0:5307f49cd305 1 // Lab 3 Example Program 2
WilliamMarshQMUL 0:5307f49cd305 2 // -----------------------
WilliamMarshQMUL 0:5307f49cd305 3 // Periodically write to the AnalogOut to create a sine wave
WilliamMarshQMUL 0:5307f49cd305 4 // Alternate between two fixed frequencies every 5 sec
WilliamMarshQMUL 0:5307f49cd305 5 //
WilliamMarshQMUL 0:5307f49cd305 6 // THIS VERSION HAS DEBUGGING CODE USING THE SERIAL PORT
WilliamMarshQMUL 0:5307f49cd305 7
WilliamMarshQMUL 1:284229960d6a 8 // Revised for mbed 5
WilliamMarshQMUL 1:284229960d6a 9
WilliamMarshQMUL 0:5307f49cd305 10 #include "mbed.h"
WilliamMarshQMUL 0:5307f49cd305 11 #include "sineTable.h"
WilliamMarshQMUL 0:5307f49cd305 12
WilliamMarshQMUL 0:5307f49cd305 13 Ticker tick ; // Creates periodic interrupt
WilliamMarshQMUL 0:5307f49cd305 14 AnalogOut ao(PTE30) ; // Analog output
WilliamMarshQMUL 0:5307f49cd305 15
WilliamMarshQMUL 0:5307f49cd305 16 // --- following code for debugging ---
WilliamMarshQMUL 0:5307f49cd305 17 Thread debugT ;
WilliamMarshQMUL 0:5307f49cd305 18 Serial pc(USBTX, USBRX); // tx, rx, useful for debugging
WilliamMarshQMUL 0:5307f49cd305 19
WilliamMarshQMUL 0:5307f49cd305 20 // Put a simple reprsentation of the sine wave
WilliamMarshQMUL 0:5307f49cd305 21 // to the serial output. ONLY at low frequency
WilliamMarshQMUL 0:5307f49cd305 22 void debug(int index) {
WilliamMarshQMUL 0:5307f49cd305 23 int sine4 = sine[index] >> 11 ; // get top 5 bits
WilliamMarshQMUL 0:5307f49cd305 24 pc.putc('*') ;
WilliamMarshQMUL 0:5307f49cd305 25 while (sine4--) pc.putc('*') ;
WilliamMarshQMUL 0:5307f49cd305 26 pc.putc('\n') ;
WilliamMarshQMUL 0:5307f49cd305 27 //pc.putc('\r') ;
WilliamMarshQMUL 0:5307f49cd305 28 }
WilliamMarshQMUL 0:5307f49cd305 29
WilliamMarshQMUL 0:5307f49cd305 30 volatile int index = 0 ; // this variable is not just for debugging!!
WilliamMarshQMUL 0:5307f49cd305 31
WilliamMarshQMUL 0:5307f49cd305 32 void debugCallback() {
WilliamMarshQMUL 0:5307f49cd305 33 while (true) {
WilliamMarshQMUL 0:5307f49cd305 34 Thread::signal_wait(0x1) ;
WilliamMarshQMUL 0:5307f49cd305 35 debug(index) ; // there is a race condition here
WilliamMarshQMUL 0:5307f49cd305 36 }
WilliamMarshQMUL 0:5307f49cd305 37 }
WilliamMarshQMUL 0:5307f49cd305 38 // ---- end of debugging code ---------
WilliamMarshQMUL 0:5307f49cd305 39
WilliamMarshQMUL 0:5307f49cd305 40 // Function called every periodically
WilliamMarshQMUL 0:5307f49cd305 41 // Write new value to AnalogOut
WilliamMarshQMUL 0:5307f49cd305 42 void writeAout() {
WilliamMarshQMUL 0:5307f49cd305 43 ao.write_u16(sine[index]) ;
WilliamMarshQMUL 0:5307f49cd305 44 debugT.signal_set(0x1) ; // DEBUGGING low frequency only
WilliamMarshQMUL 0:5307f49cd305 45 index = (index + 1) % 64 ;
WilliamMarshQMUL 0:5307f49cd305 46 }
WilliamMarshQMUL 0:5307f49cd305 47
WilliamMarshQMUL 0:5307f49cd305 48 // Control the frequency of updates
WilliamMarshQMUL 0:5307f49cd305 49 // Alternative between two frequencies
WilliamMarshQMUL 0:5307f49cd305 50 int main() {
WilliamMarshQMUL 0:5307f49cd305 51 int update_us = 100000 ; // 100ms
WilliamMarshQMUL 0:5307f49cd305 52 debugT.start(&debugCallback) ;
WilliamMarshQMUL 0:5307f49cd305 53 while (true) {
WilliamMarshQMUL 0:5307f49cd305 54 pc.printf("Update at 64 x 100ms giving about 0.15Hz\n");
WilliamMarshQMUL 0:5307f49cd305 55 tick.attach_us(callback(&writeAout), update_us); // setup ticker to write to AnalogOut
WilliamMarshQMUL 0:5307f49cd305 56 Thread::wait(30000) ; // wait 30 sec - 30000ms
WilliamMarshQMUL 0:5307f49cd305 57 update_us = 150000 ; // 150ms
WilliamMarshQMUL 0:5307f49cd305 58 pc.printf("Update at 64 x 150ms giving about 0.1Hz\n");
WilliamMarshQMUL 0:5307f49cd305 59 tick.attach_us(callback(&writeAout), update_us); // setup ticker to write to AnalogOut
WilliamMarshQMUL 0:5307f49cd305 60 Thread::wait(30000) ; // wait 30 sec - 30000ms
WilliamMarshQMUL 0:5307f49cd305 61 update_us = 100000 ; // 100ms
WilliamMarshQMUL 0:5307f49cd305 62 }
WilliamMarshQMUL 0:5307f49cd305 63 }