Diff: main.cpp

Revision:

0:3e987e5f426b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon Jan 04 14:18:40 2010 +0000
@@ -0,0 +1,44 @@
+// analog input p20 (ADC0[5], pin 3) test
+
+#include "mbed.h"
+
+int main() {
+
+    // power on, clk divider /4
+    LPC_SC->PCONP |= (1 << 12);          
+    LPC_SC->PCLKSEL0 &= ~(0x3 << 24);    
+        
+    // software-controlled ADC settings
+    LPC_ADC->ADCR = (0 << 0) // SEL: 0 = no channels selected
+              | (25 << 8)    // CLKDIV: PCLK max ~= 25MHz, /25 to give safe 1MHz
+              | (0 << 16)    // BURST: 0 = software control 
+              | (0 << 17)    // CLKS: not applicable 
+              | (1 << 21)    // PDN: 1 = operational
+              | (0 << 24)    // START: 0 = no start
+              | (0 << 27);   // EDGE: not applicable
+
+    // setup P1_31 as sel 3 (ADC), mode 2 (no pull)    
+    LPC_PINCON->PINSEL3 &= ~((unsigned int)0x3 << 30);
+    LPC_PINCON->PINSEL3 |= (unsigned int)0x3 << 30;
+    
+    LPC_PINCON->PINMODE3 &= ~((unsigned int)0x3 << 30);
+    LPC_PINCON->PINMODE3 |= (unsigned int)0x2 << 30;
+
+    while(1) {
+        // Select channel and start conversion
+        LPC_ADC->ADCR &= ~0xFF;
+        LPC_ADC->ADCR |= 1 << 5; // ADC0[5]
+        LPC_ADC->ADCR |= 1 << 24;
+    
+        // Repeatedly get the sample data until DONE bit
+        unsigned int data;
+        do {
+           data = LPC_ADC->ADGDR;
+        } while ((data & ((unsigned int)1 << 31)) == 0);
+
+        // Stop conversion    
+        LPC_ADC->ADCR &= ~(1 << 24);
+    
+        printf("0x%3X\n", data);   
+    }
+}