Diff: targets/TARGET_Maxim/TARGET_MAX32620/analogin_api.c

Revision:

149:156823d33999

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_Maxim/TARGET_MAX32620/analogin_api.c	Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,145 @@
+/*******************************************************************************
+ * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
+ * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the name of Maxim Integrated
+ * Products, Inc. shall not be used except as stated in the Maxim Integrated
+ * Products, Inc. Branding Policy.
+ *
+ * The mere transfer of this software does not imply any licenses
+ * of trade secrets, proprietary technology, copyrights, patents,
+ * trademarks, maskwork rights, or any other form of intellectual
+ * property whatsoever. Maxim Integrated Products, Inc. retains all
+ * ownership rights.
+ *******************************************************************************
+ */
+
+#include "mbed_assert.h"
+#include "analogin_api.h"
+#include "clkman_regs.h"
+#include "pwrman_regs.h"
+#include "trim_regs.h"
+#include "PeripheralPins.h"
+
+#define PGA_TRK_CNT     0x1F
+#define ADC_ACT_CNT     0x1
+#define ADC_PGA_CNT     0x1
+#define ADC_ACQ_CNT     0x1
+#define ADC_SLP_CNT     0x1
+
+#define ADC_FULL_SCALE          0x3FF
+#define ADC_EXTERNAL_LAST_INPUT 3
+
+// Only allow initialization once
+static int initialized = 0;
+
+//******************************************************************************
+void analogin_init(analogin_t *obj, PinName pin)
+{
+    // Make sure pin is an analog pin we can use for ADC
+    MBED_ASSERT((ADCName)pinmap_peripheral(pin, PinMap_ADC) != (ADCName)NC);
+
+    // Set the object pointer
+    obj->adc = MXC_ADC;
+    obj->adc_pin = pin;
+
+    if (initialized == 0) {
+        // Enable AFE power
+        MXC_PWRMAN->pwr_rst_ctrl |= MXC_F_PWRMAN_PWR_RST_CTRL_AFE_POWERED;
+
+        // Enable the clock
+        MXC_CLKMAN->clk_ctrl |= MXC_F_CLKMAN_CLK_CTRL_ADC_CLOCK_ENABLE;
+
+        // Enable clock gate
+        MXC_CLKMAN->clk_gate_ctrl2 |= MXC_F_CLKMAN_CLK_GATE_CTRL2_ADC_CLK_GATER;
+
+        // Enable interface clock
+        obj->adc->ctrl |= MXC_F_ADC_CTRL_ADC_CLK_EN;
+
+        if ((MXC_TRIM->reg11_adc_trim0 == 0xFFFFFFFF) && (MXC_TRIM->reg12_adc_trim1 == 0xFFFFFFFF)) {
+            // Set default trim for untrimmed parts.
+            MXC_TRIM->reg11_adc_trim0 = 0x02000200;
+            MXC_TRIM->reg12_adc_trim1 = 0x02000200;
+        }
+
+        // Clear ADC ready interrupt (wite 1 to clr)
+        obj->adc->intr = (obj->adc->intr & 0xFFFF) | MXC_F_ADC_INTR_ADC_REF_READY_IF;
+
+        // Using internal reference of 1.20V
+
+        // Enable ADC power bypass the buffer
+        obj->adc->ctrl |= (MXC_F_ADC_CTRL_ADC_PU | MXC_F_ADC_CTRL_ADC_REFBUF_PU |
+                           MXC_F_ADC_CTRL_ADC_CHGPUMP_PU | MXC_F_ADC_CTRL_BUF_BYPASS);
+
+        // Wait for ADC ready
+        while (!(obj->adc->intr & MXC_F_ADC_INTR_ADC_REF_READY_IF));
+
+        initialized = 1;
+    }
+}
+
+//******************************************************************************
+float analogin_read(analogin_t *obj)
+{
+    // Convert integer to float
+    return (((float)analogin_read_u16(obj)/(float)ADC_FULL_SCALE));
+}
+
+//******************************************************************************
+uint16_t analogin_read_u16(analogin_t *obj)
+{
+    // Set the pin to take readings from
+    uint32_t adc_input = PINNAME_TO_PIN(obj->adc_pin);
+
+    // Select the channel
+    obj->adc->ctrl &= ~MXC_F_ADC_CTRL_ADC_CHSEL;
+    obj->adc->ctrl |= (adc_input << MXC_F_ADC_CTRL_ADC_CHSEL_POS) & MXC_F_ADC_CTRL_ADC_CHSEL;
+
+    // We want unity gain, to get full 0-Vref range
+    // So, both ref and adc input scale should be enabled
+    obj->adc->ctrl |= MXC_F_ADC_CTRL_ADC_SCALE | MXC_F_ADC_CTRL_ADC_REFSCL;
+
+    // Not using internal buffer, disable anyway
+    obj->adc->ctrl &= ~MXC_F_ADC_CTRL_BUF_PU;
+    obj->adc->ctrl |= MXC_F_ADC_CTRL_BUF_BYPASS;
+
+    // Normal LSB justified data alignment
+
+    // Not using limits
+
+    // Clear ADC done flag (wite 1 to clr)
+    obj->adc->intr = (obj->adc->intr & 0xFFFF) | MXC_F_ADC_INTR_ADC_DONE_IF;
+
+    // Start the conversion
+    obj->adc->ctrl |= MXC_F_ADC_CTRL_CPU_ADC_START;
+
+    // Wait for ADC done
+    while (!(obj->adc->intr & MXC_F_ADC_INTR_ADC_DONE_IF));
+
+    // Get sample from the fifo
+    uint16_t sample = obj->adc->data;
+
+    // Check for overflow, hardware will report overflow as 0
+    if (obj->adc->status & MXC_F_ADC_STATUS_ADC_OVERFLOW) {
+        sample = (uint16_t)ADC_FULL_SCALE;
+    }
+
+    return sample;
+}