Class similar to AnalogIn that uses burst mode to run continious background conversions so when the input is read, the last value can immediatly be returned.

Fork of FastAnalogIn by Erik -

Obsolete!

Has been already merged with Erik's original repository => take the original!

  • Added support for LPC4088.
  • Fixed linker error (missing definition of static member "channel_usage")
Revision:
2:9b61d0792927
Child:
3:a9b753c25073
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FastAnalogIn_KLXX.cpp	Sat Mar 08 15:44:57 2014 +0000
@@ -0,0 +1,106 @@
+#ifdef TARGET_KLXX
+
+#include "FastAnalogIn.h"
+#include "clk_freqs.h"
+
+#define MAX_FADC            6000000
+#define CHANNELS_A_SHIFT    5
+
+/*typedef struct analogin_s fanalogin_t;
+
+void     fanalogin_init    (fanalogin_t *obj, PinName pin);
+float    fanalogin_read    (fanalogin_t *obj);
+uint16_t fanalogin_read_u16(fanalogin_t *obj);
+
+fanalogin_t _adc;*/
+
+FastAnalogIn::FastAnalogIn(PinName pin, bool enabled)
+{
+    ADCnumber = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
+    if (ADCnumber == (ADCName)NC) {
+        error("ADC pin mapping failed");
+    }
+
+    SIM->SCGC6 |= SIM_SCGC6_ADC0_MASK;
+
+    uint32_t port = (uint32_t)pin >> PORT_SHIFT;
+    SIM->SCGC5 |= 1 << (SIM_SCGC5_PORTA_SHIFT + port);
+
+    uint32_t cfg2_muxsel = ADC_CFG2_MUXSEL_MASK;
+    if (ADCnumber & (1 << CHANNELS_A_SHIFT)) {
+        cfg2_muxsel = 0;
+    }
+    
+    // bus clk
+    uint32_t PCLK = bus_frequency();
+    uint32_t clkdiv;
+    for (clkdiv = 0; clkdiv < 4; clkdiv++) {
+        if ((PCLK >> clkdiv) <= MAX_FADC)
+            break;
+    }
+    if (clkdiv == 4)                    //Set max div
+        clkdiv = 0x7;
+
+    ADC0->SC1[1] = ADC_SC1_ADCH(ADCnumber & ~(1 << CHANNELS_A_SHIFT));
+
+    ADC0->CFG1 = ADC_CFG1_ADIV(clkdiv & 0x3)    // Clock Divide Select: (Input Clock)/8
+               | ADC_CFG1_MODE(3)               // (16)bits Resolution
+               | ADC_CFG1_ADICLK(clkdiv >> 2);  // Input Clock: (Bus Clock)/2
+
+    ADC0->CFG2 = cfg2_muxsel            // ADxxb or ADxxa channels
+               | ADC_CFG2_ADACKEN_MASK  // Asynchronous Clock Output Enable
+               | ADC_CFG2_ADHSC_MASK;   // High-Speed Configuration
+
+    ADC0->SC2 = ADC_SC2_REFSEL(0);      // Default Voltage Reference
+
+    pinmap_pinout(pin, PinMap_ADC);
+
+    //Enable channel
+    running = false;
+    enable(enabled);
+}
+
+void FastAnalogIn::enable(bool enabled)
+{
+    //If currently not running
+    if (!running) {
+        if (enabled) {
+            //Enable the ADC channel
+            ADC0->SC3 |= ADC_SC3_ADCO_MASK;       // Enable continuous conversion
+            ADC0->SC1[0] = ADC_SC1_ADCH(ADCnumber & ~(1 << CHANNELS_A_SHIFT));  //Start conversion
+            running = true;
+        } else
+            disable();
+    }
+}
+ 
+void FastAnalogIn::disable( void )
+{
+    //If currently running
+    if (running) {
+        ADC0->SC3 &= ~ADC_SC3_ADCO_MASK;      // Disable continuous conversion
+    }
+    running = false;
+}
+
+uint16_t FastAnalogIn::read_u16()
+{
+    if (!running)
+    {
+        // start conversion
+        ADC0->SC1[0] = ADC_SC1_ADCH(ADCnumber & ~(1 << CHANNELS_A_SHIFT));
+        // Wait Conversion Complete
+        while ((ADC0->SC1[0] & ADC_SC1_COCO_MASK) != ADC_SC1_COCO_MASK);
+    }
+    if(running && ((ADC0->SC1[0]&ADC_SC1_ADCH_MASK) != (ADC_SC1_ADCH(ADCnumber & ~(1 << CHANNELS_A_SHIFT)))))
+    {
+        running = false;
+        enable();
+        while ((ADC0->SC1[0] & ADC_SC1_COCO_MASK) != ADC_SC1_COCO_MASK);
+    }
+    // Return value
+    return (uint16_t)ADC0->R[0];
+}
+
+#endif //defined TARGET_KLXX
+