Helmut Schmücker / FastAnalogIn

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")

FastAnalogIn_LPC1768.cpp@4:cd84739f7640, 2014-04-20 (annotated)

Committer:
humlet
Date:
Sun Apr 20 16:23:19 2014 +0000
Revision:
4:cd84739f7640
Parent:
2:9b61d0792927 
Added support for LPC4088,; Fixed linker error (missing definition of static member)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
frankvnk 2:9b61d0792927 1 #ifdef TARGET_LPC1768
frankvnk 2:9b61d0792927 2
Sissors 0:c2a7b899e6c7 3 #include "FastAnalogIn.h"
Sissors 0:c2a7b899e6c7 4 static inline int div_round_up(int x, int y)
Sissors 0:c2a7b899e6c7 5 {
Sissors 0:c2a7b899e6c7 6 return (x + (y - 1)) / y;
Sissors 0:c2a7b899e6c7 7 }
Sissors 0:c2a7b899e6c7 8
frankvnk 2:9b61d0792927 9 static const PinMap PinMap_ADC[] = {
frankvnk 2:9b61d0792927 10 P0_23, ADC0_0, 1,
frankvnk 2:9b61d0792927 11 P0_24, ADC0_1, 1,
frankvnk 2:9b61d0792927 12 P0_25, ADC0_2, 1,
frankvnk 2:9b61d0792927 13 P0_26, ADC0_3, 1,
frankvnk 2:9b61d0792927 14 P1_30, ADC0_4, 3,
frankvnk 2:9b61d0792927 15 P1_31, ADC0_5, 3,
frankvnk 2:9b61d0792927 16 P0_2, ADC0_7, 2,
frankvnk 2:9b61d0792927 17 P0_3, ADC0_6, 2,
frankvnk 2:9b61d0792927 18 NC, NC, 0
Sissors 0:c2a7b899e6c7 19 };
Sissors 0:c2a7b899e6c7 20
humlet 4:cd84739f7640 21 int FastAnalogIn::channel_usage[8] = {0,0,0,0,0,0,0,0};
humlet 4:cd84739f7640 22
Sissors 0:c2a7b899e6c7 23 FastAnalogIn::FastAnalogIn(PinName pin, bool enabled)
Sissors 0:c2a7b899e6c7 24 {
Sissors 0:c2a7b899e6c7 25 ADCnumber = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
Sissors 0:c2a7b899e6c7 26 if (ADCnumber == (uint32_t)NC)
Sissors 0:c2a7b899e6c7 27 error("ADC pin mapping failed");
Sissors 0:c2a7b899e6c7 28 datareg = (uint32_t*) (&LPC_ADC->ADDR0 + ADCnumber);
Sissors 0:c2a7b899e6c7 29
Sissors 0:c2a7b899e6c7 30 // ensure power is turned on
Sissors 0:c2a7b899e6c7 31 LPC_SC->PCONP |= (1 << 12);
Sissors 0:c2a7b899e6c7 32 // set PCLK of ADC to /1
Sissors 0:c2a7b899e6c7 33 LPC_SC->PCLKSEL0 &= ~(0x3 << 24);
Sissors 0:c2a7b899e6c7 34 LPC_SC->PCLKSEL0 |= (0x1 << 24);
Sissors 0:c2a7b899e6c7 35 uint32_t PCLK = SystemCoreClock;
Sissors 0:c2a7b899e6c7 36
Sissors 0:c2a7b899e6c7 37 // calculate minimum clock divider
Sissors 0:c2a7b899e6c7 38 // clkdiv = divider - 1
Sissors 0:c2a7b899e6c7 39 uint32_t MAX_ADC_CLK = 13000000;
Sissors 0:c2a7b899e6c7 40 uint32_t clkdiv = div_round_up(PCLK, MAX_ADC_CLK) - 1;
Sissors 0:c2a7b899e6c7 41 // Set the clkdiv
Sissors 0:c2a7b899e6c7 42 LPC_ADC->ADCR &= ~(255<<8);
Sissors 0:c2a7b899e6c7 43 LPC_ADC->ADCR |= clkdiv<<8;
Sissors 0:c2a7b899e6c7 44
Sissors 0:c2a7b899e6c7 45 //Enable ADC:
Sissors 0:c2a7b899e6c7 46 LPC_ADC->ADCR |= 1<<21;
Sissors 0:c2a7b899e6c7 47
Sissors 0:c2a7b899e6c7 48 //Enable burstmode, set start as zero
Sissors 0:c2a7b899e6c7 49 LPC_ADC->ADCR |= 1<<16;
Sissors 0:c2a7b899e6c7 50 LPC_ADC->ADCR &= ~(7<<24);
Sissors 0:c2a7b899e6c7 51
Sissors 0:c2a7b899e6c7 52 //Map pins
Sissors 0:c2a7b899e6c7 53 pinmap_pinout(pin, PinMap_ADC);
Sissors 0:c2a7b899e6c7 54
Sissors 0:c2a7b899e6c7 55 //Enable channel
Sissors 0:c2a7b899e6c7 56 running = false;
Sissors 0:c2a7b899e6c7 57 enable(enabled);
Sissors 0:c2a7b899e6c7 58
Sissors 0:c2a7b899e6c7 59 }
Sissors 0:c2a7b899e6c7 60
Sissors 0:c2a7b899e6c7 61 void FastAnalogIn::enable(bool enabled)
Sissors 0:c2a7b899e6c7 62 {
Sissors 0:c2a7b899e6c7 63 //If currently not running
Sissors 0:c2a7b899e6c7 64 if (!running) {
Sissors 0:c2a7b899e6c7 65 if (enabled) {
Sissors 0:c2a7b899e6c7 66 //Enable the ADC channel
Sissors 0:c2a7b899e6c7 67 channel_usage[ADCnumber]++;
Sissors 0:c2a7b899e6c7 68 LPC_ADC->ADCR |= (1<<ADCnumber);
Sissors 0:c2a7b899e6c7 69 running = true;
Sissors 0:c2a7b899e6c7 70 } else
Sissors 0:c2a7b899e6c7 71 disable();
Sissors 0:c2a7b899e6c7 72 }
frankvnk 2:9b61d0792927 73 }
Sissors 0:c2a7b899e6c7 74
Sissors 0:c2a7b899e6c7 75 void FastAnalogIn::disable( void )
Sissors 0:c2a7b899e6c7 76 {
Sissors 0:c2a7b899e6c7 77 //If currently running
Sissors 0:c2a7b899e6c7 78 if (running) {
Sissors 0:c2a7b899e6c7 79 channel_usage[ADCnumber]--;
Sissors 0:c2a7b899e6c7 80
Sissors 0:c2a7b899e6c7 81 if (channel_usage[ADCnumber]==0)
Sissors 0:c2a7b899e6c7 82 LPC_ADC->ADCR &= ~(1<<ADCnumber);
Sissors 0:c2a7b899e6c7 83 }
Sissors 0:c2a7b899e6c7 84 running = false;
frankvnk 2:9b61d0792927 85 }
Sissors 0:c2a7b899e6c7 86
Sissors 0:c2a7b899e6c7 87 unsigned short FastAnalogIn::read_u16( void )
Sissors 0:c2a7b899e6c7 88 {
Sissors 1:575f4d2d6e9c 89 volatile unsigned int retval;
Sissors 0:c2a7b899e6c7 90 //If object is enabled return current value of datareg
Sissors 1:575f4d2d6e9c 91 if (running )
Sissors 1:575f4d2d6e9c 92 retval = *datareg;
Sissors 1:575f4d2d6e9c 93
Sissors 0:c2a7b899e6c7 94 //If it isn't running, enable it and wait until new value is written to datareg
Sissors 0:c2a7b899e6c7 95 else {
Sissors 0:c2a7b899e6c7 96 //Force a read to clear done bit, enable the ADC channel
Sissors 1:575f4d2d6e9c 97 retval = *datareg;
Sissors 0:c2a7b899e6c7 98 enable();
Sissors 0:c2a7b899e6c7 99 //Wait until it is converted
Sissors 0:c2a7b899e6c7 100 while(1) {
Sissors 0:c2a7b899e6c7 101 wait_us(1);
Sissors 0:c2a7b899e6c7 102 retval = *datareg;
Sissors 0:c2a7b899e6c7 103 if ((retval>>31) == 1)
Sissors 0:c2a7b899e6c7 104 break;
Sissors 0:c2a7b899e6c7 105 }
Sissors 0:c2a7b899e6c7 106
Sissors 0:c2a7b899e6c7 107 //Do a second conversion since first one always fails for some reason
Sissors 0:c2a7b899e6c7 108 while(1) {
Sissors 0:c2a7b899e6c7 109 wait_us(1);
Sissors 0:c2a7b899e6c7 110 retval = *datareg;
Sissors 0:c2a7b899e6c7 111 if ((retval>>31) == 1)
Sissors 0:c2a7b899e6c7 112 break;
Sissors 0:c2a7b899e6c7 113 }
Sissors 0:c2a7b899e6c7 114
Sissors 0:c2a7b899e6c7 115 //Disable again
Sissors 0:c2a7b899e6c7 116 disable();
Sissors 0:c2a7b899e6c7 117 }
Sissors 1:575f4d2d6e9c 118
Sissors 1:575f4d2d6e9c 119 //Do same thing as standard mbed lib, unused bit 0-3, replicate 4-7 in it
Sissors 1:575f4d2d6e9c 120 retval &= ~0xFFFF000F;
Sissors 1:575f4d2d6e9c 121 retval |= (retval >> 8) & 0x000F;
Sissors 1:575f4d2d6e9c 122 return retval;
Sissors 0:c2a7b899e6c7 123
Sissors 0:c2a7b899e6c7 124 }
frankvnk 2:9b61d0792927 125 #endif //defined TARGET_LPC1768