Contiki 2.6
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00001 /* 00002 * Copyright (c) 2010, Mariano Alvira <mar@devl.org> and other contributors 00003 * to the MC1322x project (http://mc1322x.devl.org) 00004 * All rights reserved. 00005 * 00006 * Redistribution and use in source and binary forms, with or without 00007 * modification, are permitted provided that the following conditions 00008 * are met: 00009 * 1. Redistributions of source code must retain the above copyright 00010 * notice, this list of conditions and the following disclaimer. 00011 * 2. Redistributions in binary form must reproduce the above copyright 00012 * notice, this list of conditions and the following disclaimer in the 00013 * documentation and/or other materials provided with the distribution. 00014 * 3. Neither the name of the Institute nor the names of its contributors 00015 * may be used to endorse or promote products derived from this software 00016 * without specific prior written permission. 00017 * 00018 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 00019 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 00020 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 00021 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 00022 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 00023 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 00024 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 00025 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 00026 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 00027 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 00028 * SUCH DAMAGE. 00029 * 00030 * This file is part of libmc1322x: see http://mc1322x.devl.org 00031 * for details. 00032 * 00033 * 00034 */ 00035 00036 #include <stdint.h> 00037 #include "crm.h" 00038 #include "adc.h" 00039 #include "gpio-util.h" 00040 00041 //#define ADC_CHANS_ENABLED 0x3F // channels 0-5 enabled 00042 //#define ADC_CHANS_ENABLED 0x7E // channels 1-6 enabled 00043 //#define ADC_CHANS_ENABLED (1 << 6) // only channel 6 enabled 00044 #define ADC_CHANS_ENABLED 0x1FF // all channels, including battery reference voltage 00045 00046 //#define ADC_PRESCALE_VALUE 24 // divide by 24 for 1MHz. 00047 00048 #define ADC_SAMPLE_FREQ 400 // Hz (minimum of ~366.21 Hz) 00049 #define ADC_PRESCALE_VALUE (REF_OSC / ADC_SAMPLE_FREQ) 00050 00051 #define ADC_USE_TIMER 0 00052 #define ADC_USE_INTERRUPTS 0 // incomplete support 00053 00054 uint16_t adc_reading[NUM_ADC_CHAN]; 00055 00056 void ADC_flush(void) { 00057 while(ADC->FIFO_STATUSbits.EMPTY == 0) ADC->FIFO_READ; 00058 } 00059 00060 uint16_t ADC_READ(void) { 00061 while(ADC->FIFO_STATUSbits.EMPTY); // loop while empty 00062 return ADC->FIFO_READ; // upper 4 bits are channel number 00063 } 00064 00065 00066 void adc_service(void) { 00067 uint16_t value; 00068 uint8_t channel; 00069 while (ADC->FIFO_STATUSbits.EMPTY == 0) { 00070 value = ADC->FIFO_READ; 00071 channel = value >> 12; 00072 if (channel < NUM_ADC_CHAN) adc_reading[channel] = value & 0xFFF; 00073 } 00074 } 00075 00076 void adc_init(void) { 00077 uint8_t n; 00078 00079 ADC->CLOCK_DIVIDER = 80; // 300 KHz 00080 ADC->PRESCALE = ADC_PRESCALE_VALUE - 1; // divide by 24 for 1MHz. 00081 00082 ADC->CONTROL = 1; 00083 00084 // The ON-TIME must always be 10µs or greater - typical On-Time value = 0x000A (10dec) 00085 ADC->ON_TIME = 10; 00086 00087 /* 00088 NOTE 00089 The ADC analog block requires 6 ADC_Clocks per conversion, and the 00090 ADC_Clock must 300kHz or less. With 6 clocks/conversion and a 33.33µs 00091 clock period: 00092 * The ADC convert time must always be 20µs or greater 00093 * If the ADC_Clock is a frequency lower than 300kHz, the convert time 00094 must always be 6 ADC_Clock periods or greater 00095 * For override mode, extend convert time to 40µs minimum or greater 00096 For the convert time: 00097 * This delay is a function of the Prescale Clock (typically 1 MHz) 00098 * The register must be initialized for proper operation 00099 * For a 20µs convert time with 1MHz, value = 0x0014 (20dec) 00100 * If convert time is insufficient, inaccurate sample data will result 00101 */ 00102 ADC->CONVERT_TIME = 1000000 / (115200 / 8) - 1; 00103 00104 ADC->MODE = 0; // Automatic 00105 00106 #if ADC_USE_INTERRUPTS 00107 ADC->FIFO_CONTROL = 7; 00108 #else 00109 ADC->FIFO_CONTROL = 0; 00110 #endif 00111 00112 #if ADC_USE_TIMER 00113 ADC->SR_1_HIGH = 0x0000; 00114 ADC->SR_1_LOW = (REF_OSC / ADC_PRESCALE_VALUE) / (115200 / 8) + 1; 00115 #endif 00116 00117 ADC->SEQ_1 = 0 00118 #if ADC_USE_TIMER 00119 | (1 << 15) // sequence based on Timer 1. 00120 #else 00121 | (0 << 15) // sequence based on convert time. 00122 #endif 00123 | ADC_CHANS_ENABLED; 00124 00125 ADC->CONTROL = 0xF001 00126 //#if ADC_USE_TIMER 00127 | (1 << 1) // Timer 1 enable 00128 //#endif 00129 ; 00130 ADC->OVERRIDE = (1 << 8); 00131 00132 for (n=0; n<=8; n++) { 00133 if ((ADC_CHANS_ENABLED >> n) & 1) { 00134 gpio_select_function(30 + n, 1); // Function 1 = ADC 00135 gpio_set_pad_dir(30 + n, PAD_DIR_INPUT); 00136 } 00137 } 00138 }