cc2538: Add adc driver and example

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-04 20:39:56 +01:00 · 2013-11-04 20:39:56 +01:00 · dbba311270
commit dbba311270
parent 79e6514c80
13 changed files with 511 additions and 4 deletions
--- a/cpu/cc2538/dev/adc.c
+++ b/cpu/cc2538/dev/adc.c
@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2013, ADVANSEE - http://www.advansee.com/
+ * Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+/**
+ * \addtogroup cc2538-adc
+ * @{
+ *
+ * \file
+ * Implementation of the cc2538 ADC driver
+ */
+#include "contiki.h"
+#include "dev/soc-adc.h"
+#include "dev/cctest.h"
+#include "dev/rfcore-xreg.h"
+#include "dev/adc.h"
+#include "reg.h"
+
+#include <stdint.h>
+
+/*---------------------------------------------------------------------------*/
+void
+adc_init(void)
+{
+  /* Start conversions only manually */
+  REG(SOC_ADC_ADCCON1) |= SOC_ADC_ADCCON1_STSEL;
+}
+/*---------------------------------------------------------------------------*/
+int16_t
+adc_get(uint8_t channel, uint8_t ref, uint8_t div)
+{
+  uint32_t cctest_tr0, rfcore_xreg_atest;
+  int16_t res;
+
+  /* On-chip temperature sensor */
+  if(channel == SOC_ADC_ADCCON_CH_TEMP) {
+    /* Connect the temperature sensor to the ADC */
+    cctest_tr0 = REG(CCTEST_TR0);
+    REG(CCTEST_TR0) = cctest_tr0 | CCTEST_TR0_ADCTM;
+
+    /* Enable the temperature sensor */
+    rfcore_xreg_atest = REG(RFCORE_XREG_ATEST);
+    REG(RFCORE_XREG_ATEST) = (rfcore_xreg_atest & ~RFCORE_XREG_ATEST_ATEST_CTRL) |
+                             RFCORE_XREG_ATEST_ATEST_CTRL_TEMP;
+  }
+
+  /* Start a single extra conversion with the given parameters */
+  REG(SOC_ADC_ADCCON3) = (REG(SOC_ADC_ADCCON3) &
+                          ~(SOC_ADC_ADCCON3_EREF | SOC_ADC_ADCCON3_EDIV | SOC_ADC_ADCCON3_ECH)) |
+                         ref | div | channel;
+
+  /* Poll until end of conversion */
+  while(!(REG(SOC_ADC_ADCCON1) & SOC_ADC_ADCCON1_EOC));
+
+  /* Read conversion result, reading SOC_ADC_ADCH last to clear
+   * SOC_ADC_ADCCON1.EOC */
+  res  = REG(SOC_ADC_ADCL) & 0xfc;
+  res |= REG(SOC_ADC_ADCH) << 8;
+
+  /* On-chip temperature sensor */
+  if(channel == SOC_ADC_ADCCON_CH_TEMP) {
+    /* Restore the initial temperature sensor state and connection (better for
+     * power consumption) */
+    REG(RFCORE_XREG_ATEST) = rfcore_xreg_atest;
+    REG(CCTEST_TR0) = cctest_tr0;
+  }
+
+  /* Return conversion result */
+  return res;
+}
+
+/** @} */