jim hamblen / Mbed 2 deprecated i2s_microphone

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Dependencies:   I2S mbed

Fork of flash_audio_playerI2S by jim hamblen

main.cpp@2:04ffcc436ac0, 2018-01-26 (annotated)

Committer:
4180_1
Date:
Fri Jan 26 00:55:11 2018 +0000
Revision:
2:04ffcc436ac0
Parent:
1:8fda76e11be8 
ver 1.0

Who changed what in which revision?

UserRevisionLine numberNew contents of line
4180_1 0:e4f991474a45 1 #include "mbed.h"
4180_1 2:04ffcc436ac0 2 //I2S Demo to display values from I2S microphone
4180_1 2:04ffcc436ac0 3 //
4180_1 2:04ffcc436ac0 4 //Only works on mbed LPC1768 - I2S is not an mbed API!
4180_1 2:04ffcc436ac0 5 //Microphone used is SPH0645LM4H
4180_1 2:04ffcc436ac0 6 //see https://www.adafruit.com/product/3421
4180_1 2:04ffcc436ac0 7
4180_1 1:8fda76e11be8 8 #include "I2S.h"
4180_1 2:04ffcc436ac0 9 //uses patched mbed I2S library from
4180_1 2:04ffcc436ac0 10 //https://os.mbed.com/users/p07gbar/code/I2S/
4180_1 2:04ffcc436ac0 11 //Needed a typo patch - clock was swapped p30/p15 in pin function setup code
4180_1 2:04ffcc436ac0 12 //"if (_clk == p15)" changed to "if (_clk != p15)" in I2S.cpp line 494
4180_1 2:04ffcc436ac0 13 BusOut mylevel(LED4,LED3,LED2,LED1);
4180_1 2:04ffcc436ac0 14 //4 built in mbed LEDs display audio level
4180_1 2:04ffcc436ac0 15
4180_1 2:04ffcc436ac0 16 #define sample_freq 32000.0
4180_1 1:8fda76e11be8 17
4180_1 2:04ffcc436ac0 18 //Uses I2S hardware for input
4180_1 2:04ffcc436ac0 19 I2S i2srx(I2S_RECEIVE, p17, p16, p15);
4180_1 2:04ffcc436ac0 20 //p17(PWM value sent as serial data bit) <-> Dout
4180_1 2:04ffcc436ac0 21 //p16(WS) <-> LRC left/right channel clock
4180_1 2:04ffcc436ac0 22 //p15(bit clock) <-> BCLK
4180_1 2:04ffcc436ac0 23
4180_1 2:04ffcc436ac0 24 volatile int i=0;
4180_1 0:e4f991474a45 25
4180_1 2:04ffcc436ac0 26 void i2s_isr() //interrupt routine to read microphone
4180_1 2:04ffcc436ac0 27 {
4180_1 2:04ffcc436ac0 28 i = i2srx.read();//read value using I2S input
4180_1 2:04ffcc436ac0 29 mylevel = (i>>7)& 0xF; //Display Audio Level on 4 LEDs
4180_1 2:04ffcc436ac0 30 }
4180_1 2:04ffcc436ac0 31 int main()
4180_1 0:e4f991474a45 32 {
4180_1 2:04ffcc436ac0 33 i2srx.stereomono(I2S_MONO);//mono not stereo mode
4180_1 2:04ffcc436ac0 34 i2srx.masterslave(I2S_MASTER);//master drives clocks
4180_1 2:04ffcc436ac0 35 i2srx.frequency(sample_freq);//set sample freq
4180_1 2:04ffcc436ac0 36 i2srx.set_interrupt_fifo_level(1);//interrupt on one sample
4180_1 2:04ffcc436ac0 37 i2srx.attach(&i2s_isr);//set I2S ISR
4180_1 2:04ffcc436ac0 38 i2srx.start();//start I2S and interrupts
4180_1 2:04ffcc436ac0 39 while(1) {
4180_1 2:04ffcc436ac0 40 printf("%X\n\r",(i>>16)&(0x0000FFFF));
4180_1 2:04ffcc436ac0 41 wait(0.5);
4180_1 0:e4f991474a45 42 }
4180_1 0:e4f991474a45 43 }