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. This slightly modified version allows NC pins.
Dependents: Pinscape_Controller
Fork of FastAnalogIn by
Diff: FastAnalogIn_LPC11UXX.cpp
- Revision:
- 8:68082fdde730
- Child:
- 10:afc3b84dbbd6
diff -r 965a2b0e477f -r 68082fdde730 FastAnalogIn_LPC11UXX.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/FastAnalogIn_LPC11UXX.cpp Sat Jun 28 13:01:27 2014 +0000 @@ -0,0 +1,114 @@ +#ifdef TARGET_LPC11UXX + +#include "FastAnalogIn.h" +static inline int div_round_up(int x, int y) +{ + return (x + (y - 1)) / y; +} + +#define LPC_IOCON0_BASE (LPC_IOCON_BASE) +#define LPC_IOCON1_BASE (LPC_IOCON_BASE + 0x60) +#define MAX_ADC_CLK 4500000 + +static const PinMap PinMap_ADC[] = { + {P0_11, ADC0_0, 0x02}, + {P0_12, ADC0_1, 0x02}, + {P0_13, ADC0_2, 0x02}, + {P0_14, ADC0_3, 0x02}, + {P0_15, ADC0_4, 0x02}, + {P0_16, ADC0_5, 0x01}, + {P0_22, ADC0_6, 0x01}, + {P0_23, ADC0_7, 0x01}, + {NC , NC , 0 } +}; + +static int channel_usage[8] = {0,0,0,0,0,0,0,0}; + + + +FastAnalogIn::FastAnalogIn(PinName pin, bool enabled) +{ + ADCnumber = (ADCName)pinmap_peripheral(pin, PinMap_ADC); + if (ADCnumber == (uint32_t)NC) + error("ADC pin mapping failed"); + datareg = (uint32_t*) (&LPC_ADC->DR0 + ADCnumber); + + // Power up ADC + LPC_SYSCON->PDRUNCFG &= ~ (1 << 4); + LPC_SYSCON->SYSAHBCLKCTRL |= ((uint32_t)1 << 13); + + uint32_t pin_number = (uint32_t)pin; + __IO uint32_t *reg = (pin_number < 32) ? (__IO uint32_t*)(LPC_IOCON0_BASE + 4 * pin_number) : (__IO uint32_t*)(LPC_IOCON1_BASE + 4 * (pin_number - 32)); + + // set pin to ADC mode + *reg &= ~(1 << 7); // set ADMODE = 0 (analog mode) + + uint32_t clkdiv = div_round_up(SystemCoreClock, MAX_ADC_CLK) - 1; + + LPC_ADC->CR = (0 << 0) // no channels selected + | (clkdiv << 8) // max of 4.5MHz + | (1 << 16) // BURST = 1, hardware controlled + | ( 0 << 17 ); // CLKS = 0, we stick to 10 bit mode + + 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 + channel_usage[ADCnumber]++; + LPC_ADC->CR |= (1<<ADCnumber); + running = true; + } else + disable(); + } +} + +void FastAnalogIn::disable( void ) +{ + //If currently running + if (running) { + channel_usage[ADCnumber]--; + + if (channel_usage[ADCnumber]==0) + LPC_ADC->CR &= ~(1<<ADCnumber); + } + running = false; +} + +unsigned short FastAnalogIn::read_u16( void ) +{ + unsigned int retval; + //If object is enabled return current value of datareg + if (running) + retval = *datareg; + + //If it isn't running, enable it and wait until new value is written to datareg + else { + //Force a read to clear done bit, enable the ADC channel + retval = *datareg; + enable(); + //Wait until it is converted + while(1) { + retval = *datareg; + if ((retval>>31) == 1) + break; + } + //Disable again + disable(); + } + + //Do same thing as standard mbed lib, unused bit 0-3, replicate 4-7 in it + retval &= ~0xFFFF003F; + retval |= (retval >> 6) & 0x003F; + return retval; +} +#endif //defined TARGET_LPC11UXX