Diff: main.cpp

Revision:

0:33edf726559b

Child:

1:2b95f921e7f2

diff -r 000000000000 -r 33edf726559b main.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed Oct 07 13:04:40 2020 +0000
@@ -0,0 +1,69 @@
+/*
+*
+* Connections
+* L432KC D3   --- SS PmodMIC3
+* L432KC D12  --- MISO PmodMIC3
+* L432KC D13  --- SCK PmodMIC3
+* GND         --- GND PmodMIC3
+* Vcc         --- VCC PmodMIC3
+*
+* Pmod MIC3
+* https://reference.digilentinc.com/reference/pmod/pmodmic3/start
+* ADC7476
+* https://www.ti.com/lit/ds/symlink/adcs7476.pdf
+*
+* Timo Karppinen 7.10.2020
+**************************************************/
+#include  "mbed.h"
+
+SPI spi(D11, D12, D13); // mosi, miso, sclk
+DigitalOut mic3cs(D3);
+
+
+int raw = 0;        // 16 bits from MIC3
+int sound32bit = 0;
+int sound = 0;
+DigitalOut LED(D9);
+
+
+int main()
+{
+    // Chip must be deselected
+    mic3cs.write(1);
+
+    // Setup the spi for 16 bit data, low steady state clock,
+    // rising edge capture, with a 1MHz clock rate
+    spi.format(16, 0);
+    spi.frequency(1000000);     
+    ThisThread::sleep_for(100ms);
+    
+    while(1){
+    // Select the device by seting chip select low
+    mic3cs.write(0);
+    ThisThread::sleep_for(1ms);  // > 100 ns for the MAX31855
+    
+    // Send 0x0000 to nowhere to read the 16 bits
+    raw = spi.write(0x0000);
+    
+    ThisThread::sleep_for(1ms);
+
+    // Deselect the device
+    mic3cs.write(1);
+    printf("16 bits MIC3 = 0x%X", raw);
+    
+    // It is a two's complement for negative numbers. The sign is now on the 12th bit.
+    
+    sound32bit = raw << 22; // 22 bits to the left to create 32 bit two's complement
+    sound = sound32bit / 16777216; // 2 exp24 = 16 7777 216  means shifting 24 bits left without shifting the sign!
+    printf("   sound 12 bit = %d\n", sound);
+   
+    if(sound > 128){
+        LED.write(1);
+        }
+        else{
+            LED.write(0);
+            }
+    ThisThread::sleep_for(200ms);
+    }
+}
+