mbed library sources
Dependents: frdm_kl05z_gpio_test
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targets/hal/TARGET_NXP/TARGET_LPC408X/analogin_api.c
- Committer:
- mbed_official
- Date:
- 2013-09-23
- Revision:
- 29:6ac4027eff2b
- Parent:
- 15:4892fe388435
- Child:
- 227:7bd0639b8911
File content as of revision 29:6ac4027eff2b:
/* 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" #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; } static const PinMap PinMap_ADC[] = { {P0_23, ADC0_0, 0x01}, {P0_24, ADC0_1, 0x01}, {P0_25, ADC0_2, 0x01}, {P0_26, ADC0_3, 0x01}, {P1_30, ADC0_4, 0x03}, {P1_31, ADC0_5, 0x03}, {P0_12, ADC0_6, 0x03}, {P0_13, ADC0_7, 0x03}, {NC , NC , 0 } }; #define ADC_RANGE ADC_12BIT_RANGE void analogin_init(analogin_t *obj, PinName pin) { obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC); if (obj->adc == (ADCName)NC) { error("ADC pin mapping failed"); } // ensure power is turned on LPC_SC->PCONP |= (1 << 12); uint32_t PCLK = PeripheralClock; // calculate minimum clock divider // clkdiv = divider - 1 uint32_t MAX_ADC_CLK = 12400000; uint32_t clkdiv = div_round_up(PCLK, MAX_ADC_CLK) - 1; // Set the generic software-controlled ADC settings LPC_ADC->CR = (0 << 0) // SEL: 0 = no channels selected | (clkdiv << 8) // CLKDIV: | (0 << 16) // BURST: 0 = software control | (1 << 21) // PDN: 1 = operational | (0 << 24) // START: 0 = no start | (0 << 27); // EDGE: not applicable // must enable analog mode (ADMODE = 0) __IO uint32_t *reg = (__IO uint32_t*) (LPC_IOCON_BASE + 4 * pin); *reg &= ~(1 << 7); 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 >> 4) & ADC_RANGE; // 12 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 << 4) | ((value >> 8) & 0x000F); // 12 bit } float analogin_read(analogin_t *obj) { uint32_t value = adc_read_u32(obj); return (float)value * (1.0f / (float)ADC_RANGE); }