Kevin Hetterscheid / EMG

emg

Fork of EMG by Tom Tom

main.cpp@12:768048d7f742, 2014-09-11 (annotated)

Committer:
vsluiter
Date:
Thu Sep 11 07:19:37 2014 +0000
Revision:
12:768048d7f742
Parent:
10:09b8424a7b39 
Added comment that 12-bit value is converted to be 16-bit full scale (raw value multiplied by 16 / shifted 4 bits)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
vsluiter 0:32bb76391d89 1 #include "mbed.h"
vsluiter 6:80c13d99aa55 2 #include "MODSERIAL.h"
vsluiter 0:32bb76391d89 3
vsluiter 4:8b298dfada81 4 //Define objects
vsluiter 7:3396c3e33928 5 AnalogIn emg0(PTB1); //Analog input
ArvidKeemink 1:db54d9412d18 6 PwmOut red(LED_RED); //PWM output
vsluiter 8:8a17f65622b4 7 Ticker log_timer;
vsluiter 8:8a17f65622b4 8 MODSERIAL pc(USBTX,USBRX);
vsluiter 2:e314bb3b2d99 9
vsluiter 4:8b298dfada81 10 /** Looper function
vsluiter 4:8b298dfada81 11 * functions used for Ticker and Timeout should be of type void <name>(void)
vsluiter 4:8b298dfada81 12 * i.e. no input arguments, no output arguments.
vsluiter 4:8b298dfada81 13 * if you want to change a variable that you use in other places (for example in main)
vsluiter 4:8b298dfada81 14 * you will have to make that variable global in order to be able to reach it both from
vsluiter 4:8b298dfada81 15 * the function called at interrupt time, and in the main function.
vsluiter 4:8b298dfada81 16 * To make a variable global, define it under the includes.
vsluiter 4:8b298dfada81 17 * variables that are changed in the interrupt routine (written to) should be made
vsluiter 4:8b298dfada81 18 * 'volatile' to let the compiler know that those values may change outside the current context.
vsluiter 8:8a17f65622b4 19 * i.e.: "volatile uint16_t emg_value;" instead of "uint16_t emg_value"
vsluiter 4:8b298dfada81 20 * in the example below, the variable is not re-used in the main function, and is thus declared
vsluiter 4:8b298dfada81 21 * local in the looper function only.
vsluiter 4:8b298dfada81 22 **/
vsluiter 2:e314bb3b2d99 23 void looper()
vsluiter 2:e314bb3b2d99 24 {
vsluiter 4:8b298dfada81 25 /*variable to store value in*/
vsluiter 8:8a17f65622b4 26 uint16_t emg_value;
vsluiter 4:8b298dfada81 27 /*put raw emg value both in red and in emg_value*/
vsluiter 10:09b8424a7b39 28 red.write(emg0.read()); // read float value (0..1 = 0..3.3V)
vsluiter 12:768048d7f742 29 emg_value = emg0.read_u16(); // read direct ADC result, converted to 16 bit integer (0..2^16 = 0..65536 = 0..3.3V)
vsluiter 8:8a17f65622b4 30 /*send value to PC. Line below is used to prevent buffer overrun */
vsluiter 6:80c13d99aa55 31 if(pc.rxBufferGetSize(0)-pc.rxBufferGetCount() > 30)
vsluiter 8:8a17f65622b4 32 pc.printf("%u\n",emg_value);
vsluiter 5:4dacb7b72109 33 /**When not using the LED, the above could also have been done this way:
vsluiter 8:8a17f65622b4 34 * pc.printf("%u\n", emg0.read_u16());
vsluiter 5:4dacb7b72109 35 */
vsluiter 2:e314bb3b2d99 36 }
vsluiter 0:32bb76391d89 37
vsluiter 0:32bb76391d89 38 int main()
vsluiter 0:32bb76391d89 39 {
vsluiter 4:8b298dfada81 40 /*setup baudrate. Choose the same in your program on PC side*/
vsluiter 2:e314bb3b2d99 41 pc.baud(115200);
vsluiter 4:8b298dfada81 42 /*set the period for the PWM to the red LED*/
vsluiter 2:e314bb3b2d99 43 red.period_ms(2);
vsluiter 4:8b298dfada81 44 /**Here you attach the 'void looper(void)' function to the Ticker object
vsluiter 9:d33e7b175ad7 45 * The looper() function will be called every 0.01 seconds.
vsluiter 4:8b298dfada81 46 * Please mind that the parentheses after looper are omitted when using attach.
vsluiter 4:8b298dfada81 47 */
vsluiter 8:8a17f65622b4 48 log_timer.attach(looper, 0.01);
ArvidKeemink 1:db54d9412d18 49 while(1) //Loop
vsluiter 0:32bb76391d89 50 {
vsluiter 4:8b298dfada81 51 /*Empty!*/
vsluiter 4:8b298dfada81 52 /*Everything is handled by the interrupt routine now!*/
vsluiter 0:32bb76391d89 53 }
vsluiter 0:32bb76391d89 54 }