mbed library sources modified for open wear
Dependents: openwear-lifelogger-example
Fork of mbed-src by
Diff: targets/hal/TARGET_NXP/TARGET_LPC11XX_11CXX/analogin_api.c
- Revision:
- 30:91c1d09ada54
- Child:
- 32:4742f6c694e8
diff -r 6ac4027eff2b -r 91c1d09ada54 targets/hal/TARGET_NXP/TARGET_LPC11XX_11CXX/analogin_api.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/hal/TARGET_NXP/TARGET_LPC11XX_11CXX/analogin_api.c Wed Sep 25 10:30:04 2013 +0100 @@ -0,0 +1,114 @@ +/* mbed Microcontroller Library + * Copyright (c) 2006-2013 ARM Limited + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +#include "analogin_api.h" +#include "cmsis.h" +#include "pinmap.h" +#include "error.h" + +#include "adc_pinmap.h" + +#define ANALOGIN_MEDIAN_FILTER 1 + +#define ADC_10BIT_RANGE 0x3FF +#define ADC_12BIT_RANGE 0xFFF + +static inline int div_round_up(int x, int y) { + return (x + (y - 1)) / y; +} + +#define ADC_RANGE ADC_10BIT_RANGE + +void analogin_init(analogin_t *obj, PinName pin) { + obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC); + if (obj->adc == (uint32_t)NC) { + error("ADC pin mapping failed"); + return; + } + + // Power up ADC + LPC_SYSCON->PDRUNCFG &= ~ (1 << 4); + LPC_SYSCON->SYSAHBCLKCTRL |= ((uint32_t)1 << 13); + + uint32_t offset = (uint32_t)pin & 0xff; + __IO uint32_t *reg = (__IO uint32_t*)(LPC_IOCON_BASE + offset); + + // set pin to ADC mode + *reg &= ~(1 << 7); // set ADMODE = 0 (analog mode) + + uint32_t PCLK = SystemCoreClock; + uint32_t MAX_ADC_CLK = 4500000; + uint32_t clkdiv = div_round_up(PCLK, MAX_ADC_CLK) - 1; + + LPC_ADC->CR = (0 << 0) // no channels selected + | (clkdiv << 8) // max of 4.5MHz + | (0 << 16) // BURST = 0, software controlled + | ( 0 << 17 ); // CLKS = 0, not applicable + + pinmap_pinout(pin, PinMap_ADC); +} + +static inline uint32_t adc_read(analogin_t *obj) { + // Select the appropriate channel and start conversion + LPC_ADC->CR &= ~0xFF; + LPC_ADC->CR |= 1 << (int)obj->adc; + LPC_ADC->CR |= 1 << 24; + + // Repeatedly get the sample data until DONE bit + unsigned int data; + do { + data = LPC_ADC->GDR; + } while ((data & ((unsigned int)1 << 31)) == 0); + + // Stop conversion + LPC_ADC->CR &= ~(1 << 24); + + return (data >> 6) & ADC_RANGE; // 10 bit +} + +static inline void order(uint32_t *a, uint32_t *b) { + if (*a > *b) { + uint32_t t = *a; + *a = *b; + *b = t; + } +} + +static inline uint32_t adc_read_u32(analogin_t *obj) { + uint32_t value; +#if ANALOGIN_MEDIAN_FILTER + uint32_t v1 = adc_read(obj); + uint32_t v2 = adc_read(obj); + uint32_t v3 = adc_read(obj); + order(&v1, &v2); + order(&v2, &v3); + order(&v1, &v2); + value = v2; +#else + value = adc_read(obj); +#endif + return value; +} + +uint16_t analogin_read_u16(analogin_t *obj) { + uint32_t value = adc_read_u32(obj); + + return (value << 6) | ((value >> 4) & 0x003F); // 10 bit +} + +float analogin_read(analogin_t *obj) { + uint32_t value = adc_read_u32(obj); + return (float)value * (1.0f / (float)ADC_RANGE); +}