tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_Maxim/TARGET_MAX32610/analogin_api.c

   1 /*******************************************************************************
   2  * Copyright (C) 2015 Maxim Integrated Products, Inc., All Rights Reserved.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
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   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included
  12  * in all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  15  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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  18  * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20  * OTHER DEALINGS IN THE SOFTWARE.
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  22  * Except as contained in this notice, the name of Maxim Integrated
  23  * Products, Inc. shall not be used except as stated in the Maxim Integrated
  24  * Products, Inc. Branding Policy.
  25  *
  26  * The mere transfer of this software does not imply any licenses
  27  * of trade secrets, proprietary technology, copyrights, patents,
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  32  */
  33
  34 #include "mbed_assert.h"
  35 #include "analogin_api.h"
  36 #include "clkman_regs.h"
  37 #include "pwrman_regs.h"
  38 #include "afe_regs.h"
  39 #include "PeripheralPins.h"
  40
  41 #define PGA_TRK_CNT     0x1F
  42 #define ADC_ACT_CNT     0x1
  43 #define ADC_PGA_CNT     0x1
  44 #define ADC_ACQ_CNT     0x1
  45 #define ADC_SLP_CNT     0x1
  46
  47 //******************************************************************************
  48 void analogin_init(analogin_t *obj, PinName pin)
  49 {
  50     // Make sure pin is an analog pin we can use for ADC
  51     MBED_ASSERT((ADCName)pinmap_peripheral(pin, PinMap_ADC) != (ADCName)NC);
  52
  53     // Set the object pointer
  54     obj->adc = MXC_ADC;
  55     obj->adccfg = MXC_ADCCFG;
  56     obj->adc_fifo = MXC_ADC_FIFO;
  57     obj->adc_pin = pin;
  58
  59     // Set the ADC clock to the system clock frequency
  60     MXC_SET_FIELD(&MXC_CLKMAN->clk_ctrl, MXC_F_CLKMAN_CLK_CTRL_ADC_SOURCE_SELECT,
  61         (MXC_F_CLKMAN_CLK_CTRL_ADC_GATE_N | (MXC_E_CLKMAN_ADC_SOURCE_SELECT_SYSTEM <<
  62         MXC_F_CLKMAN_CLK_CTRL_ADC_SOURCE_SELECT_POS)));
  63
  64     // Enable AFE power
  65     MXC_PWRMAN->pwr_rst_ctrl |= MXC_F_PWRMAN_PWR_RST_CTRL_AFE_POWERED;
  66
  67     // Setup and hold window
  68     MXC_SET_FIELD(&obj->adc->tg_ctrl0, MXC_F_ADC_TG_CTRL0_PGA_TRK_CNT, PGA_TRK_CNT);
  69
  70     // Setup sampling count and timing
  71     MXC_SET_FIELD(&obj->adc->tg_ctrl1, (MXC_F_ADC_TG_CTRL1_PGA_ACQ_CNT |
  72         MXC_F_ADC_TG_CTRL1_ADC_ACQ_CNT | MXC_F_ADC_TG_CTRL1_ADC_SLP_CNT),
  73         ((ADC_PGA_CNT << MXC_F_ADC_TG_CTRL1_PGA_ACQ_CNT_POS) |
  74         (ADC_ACQ_CNT << MXC_F_ADC_TG_CTRL1_ADC_ACQ_CNT_POS) |
  75         (ADC_SLP_CNT << MXC_F_ADC_TG_CTRL1_ADC_SLP_CNT_POS) |
  76         (MXC_F_ADC_TG_CTRL1_ADC_BRST_CNT)));
  77 }
  78
  79 //******************************************************************************
  80 float analogin_read(analogin_t *obj)
  81 {
  82     // Convert integer to float
  83     return (((float)analogin_read_u16(obj)/(float)0xFFFF));
  84 }
  85
  86 //******************************************************************************
  87 uint16_t analogin_read_u16(analogin_t *obj)
  88 {
  89     // Set the pin to take readings from
  90     unsigned mux_pos;
  91     unsigned diff = 0;
  92     if(obj->adc_pin >> PORT_SHIFT == 0xB) {
  93         mux_pos = (obj->adc_pin & 0xF) + 8;
  94     } else {
  95         mux_pos = (obj->adc_pin & 0xF);
  96     }
  97
  98     if(obj->adc_pin >> PORT_SHIFT == 0xC) {
  99         diff = 1;
 100         mux_pos = (obj->adc_pin & 0xF) + 8;
 101     }
 102
 103     // Reset the ADC
 104     obj->adc->ctrl0 |= MXC_F_ADC_CTRL0_CPU_ADC_RST;
 105
 106     // Enable the ADC
 107     obj->adc->ctrl0 |= MXC_F_ADC_CTRL0_CPU_ADC_EN;
 108
 109     // Setup the ADC clock
 110     MXC_SET_FIELD(&obj->adc->ctrl0, (MXC_F_ADC_CTRL0_ADC_MODE | MXC_F_ADC_CTRL0_AVG_MODE |
 111         MXC_F_ADC_CTRL0_ADC_CLK_MODE | MXC_F_ADC_CTRL0_ADC_BI_POL),
 112         ((MXC_E_ADC_MODE_SMPLCNT_FULL_RATE << MXC_F_ADC_CTRL0_ADC_MODE_POS) |
 113         (MXC_E_ADC_AVG_MODE_FILTER_OUTPUT << MXC_F_ADC_CTRL0_AVG_MODE_POS) |
 114         (0x2 << MXC_F_ADC_CTRL0_ADC_CLK_MODE_POS) |
 115         MXC_F_ADC_CTRL0_ADC_CLK_EN));
 116
 117     // Setup the input multiplexor
 118     MXC_SET_FIELD(&obj->adc->pga_ctrl, (MXC_F_ADC_PGA_CTRL_MUX_CH_SEL |
 119         MXC_F_ADC_PGA_CTRL_MUX_DIFF | MXC_F_ADC_PGA_CTRL_PGA_GAIN),
 120         ((mux_pos << MXC_F_ADC_PGA_CTRL_MUX_CH_SEL_POS) |
 121         (diff << MXC_F_ADC_PGA_CTRL_MUX_DIFF_POS)));
 122
 123     // Setup voltage reference
 124     MXC_SET_FIELD(&MXC_AFE->ctrl1, MXC_F_AFE_CTRL1_REF_ADC_VOLT_SEL,
 125         (MXC_F_AFE_CTRL1_REF_ADC_POWERUP | MXC_F_AFE_CTRL1_REF_BLK_POWERUP |
 126         (MXC_E_AFE_REF_VOLT_SEL_1500 << MXC_F_AFE_CTRL1_REF_ADC_VOLT_SEL_POS)));
 127
 128     // Clear the done bit
 129     obj->adc->intr = MXC_F_ADC_INTR_DONE_IF;
 130
 131     // Take one sample
 132     obj->adc->tg_ctrl0 |= (1 << MXC_F_ADC_TG_CTRL0_ADC_SMPL_CNT_POS);
 133
 134     // Set the start bit to take the sample
 135     obj->adc->ctrl0 |= MXC_F_ADC_CTRL0_CPU_ADC_START;
 136
 137     // Wait for the conversion to complete
 138     while(!(obj->adc->intr & MXC_F_ADC_INTR_DONE_IF)) {}
 139
 140     // Get sample from the fifo
 141     uint16_t sample = (uint16_t)(obj->adc->out & 0xFFFF);
 142
 143     // Disable ADC
 144     obj->adc->ctrl0 &= ~MXC_F_ADC_CTRL0_CPU_ADC_EN;
 145
 146     return (sample - 1);
 147 }