From 766a2388d46f49e07ec0280fa4f3d254367850d1 Mon Sep 17 00:00:00 2001
From: utzig <utzig@35acf78f-673a-0410-8e92-d51de3d6d3f4>
Date: Sun, 29 Jun 2014 23:06:17 +0000
Subject: AVR HAL ported from RT-2 (serial/pal/hal tested)

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@6999 35acf78f-673a-0410-8e92-d51de3d6d3f4
---
 os/hal/ports/AVR/adc_lld.c | 190 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 190 insertions(+)
 create mode 100644 os/hal/ports/AVR/adc_lld.c

(limited to 'os/hal/ports/AVR/adc_lld.c')

diff --git a/os/hal/ports/AVR/adc_lld.c b/os/hal/ports/AVR/adc_lld.c
new file mode 100644
index 000000000..e41a2122e
--- /dev/null
+++ b/os/hal/ports/AVR/adc_lld.c
@@ -0,0 +1,190 @@
+/*
+    ChibiOS/RT - Copyright (C) 2006-2014 Giovanni Di Sirio
+
+    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.
+*/
+
+/**
+ * @file    AVR/adc_lld.c
+ * @brief   ADC Driver subsystem low level driver source.
+ *
+ * @addtogroup ADC
+ * @{
+ */
+
+#include "hal.h"
+
+#if HAL_USE_ADC || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Driver local definitions.                                                 */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver exported variables.                                                */
+/*===========================================================================*/
+/** @brief ADC1 driver identifier.*/
+#if AVR_ADC_USE_ADC1 || defined(__DOXYGEN__)
+ADCDriver ADCD1;
+#endif
+/*===========================================================================*/
+/* Driver local variables.                                                   */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver local functions.                                                   */
+/*===========================================================================*/
+
+static size_t getAdcChannelNumberFromMask(uint8_t mask, uint8_t currentChannel) {
+
+  for (uint8_t i = 0; mask > 0; i++) {
+    if (mask & 0x01) {
+      if (!currentChannel)
+        return i;
+      currentChannel--;
+    }
+    mask >>= 1;
+  }
+
+  /* error, should never reach this line */
+}
+
+static void setAdcChannel(uint8_t channelNum) {
+
+  ADMUX = (ADMUX & 0xf8) | (channelNum & 0x07);
+
+}
+
+/*===========================================================================*/
+/* Driver interrupt handlers.                                                */
+/*===========================================================================*/
+
+#include <util/delay.h>
+
+OSAL_IRQ_HANDLER(ADC_vect) {
+
+  OSAL_IRQ_PROLOGUE();
+  uint8_t low = ADCL;
+  uint8_t high = ADCH;
+  uint16_t result = (high << 8) | low;
+
+  ADCD1.samples[ADCD1.currentBufferPosition] = result;
+  ADCD1.currentBufferPosition++;
+
+  size_t bufferSize = ADCD1.depth * ADCD1.grpp->num_channels;
+  size_t currentChannel = ADCD1.currentBufferPosition % ADCD1.grpp->num_channels;
+  size_t currentIteration = ADCD1.currentBufferPosition / ADCD1.grpp->num_channels;
+  if (ADCD1.grpp->circular && currentChannel == 0 && currentIteration == ADCD1.depth/2) {
+    _adc_isr_half_code(&ADCD1);
+  }
+
+  if (ADCD1.currentBufferPosition == bufferSize) {
+    _adc_isr_full_code(&ADCD1);
+  } else {
+    setAdcChannel(getAdcChannelNumberFromMask(ADCD1.grpp->channelsMask,currentChannel));
+    ADCSRA |= 1 << ADSC;
+  }
+
+  OSAL_IRQ_EPILOGUE();
+}
+
+/*===========================================================================*/
+/* Driver exported functions.                                                */
+/*===========================================================================*/
+
+/**
+ * @brief   Low level ADC driver initialization.
+ *
+ * @notapi
+ */
+void adc_lld_init(void) {
+
+  adcObjectInit(&ADCD1);
+
+  //prescaler 128, only value possible at 20Mhz, interrupt
+  ADCSRA = (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0) | (1 << ADIE);
+
+  ADCSRB = 0; //single shot
+
+  //uso aref, only valid for arduino. arduino ha aref collegato
+  ADMUX = (0 << REFS1) | (0 << REFS0);
+
+}
+
+/**
+ * @brief   Configures and activates the ADC peripheral.
+ *
+ * @param[in] adcp      pointer to the @p ADCDriver object
+ *
+ * @notapi
+ */
+void adc_lld_start(ADCDriver *adcp) {
+
+  if (adcp->state == ADC_STOP) {
+    /* Clock activation.*/
+    ADCSRA |= (1 << ADEN);
+  }
+
+  if (adcp->config != NULL) {
+    ADMUX = (adcp->config->analog_reference << REFS0);
+  }
+}
+
+/**
+ * @brief   Deactivates the ADC peripheral.
+ *
+ * @param[in] adcp      pointer to the @p ADCDriver object
+ *
+ * @notapi
+ */
+void adc_lld_stop(ADCDriver *adcp) {
+
+  if (adcp->state == ADC_READY) {
+    /* Clock de-activation.*/
+    ADCSRA &= ~(1 << ADEN);
+  }
+
+}
+
+/**
+ * @brief   Starts an ADC conversion.
+ *
+ * @param[in] adcp      pointer to the @p ADCDriver object
+ *
+ * @notapi
+ */
+void adc_lld_start_conversion(ADCDriver *adcp) {
+
+  adcp->currentBufferPosition=0;
+
+  setAdcChannel(getAdcChannelNumberFromMask(adcp->grpp->channelsMask,0));
+  ADCSRA |= 1 << ADSC;
+
+}
+
+/**
+ * @brief   Stops an ongoing conversion.
+ *
+ * @param[in] adcp      pointer to the @p ADCDriver object
+ *
+ * @notapi
+ */
+void adc_lld_stop_conversion(ADCDriver *adcp) {
+
+    ADCSRA &= ~(1 << ADSC);
+
+}
+
+#endif /* HAL_USE_ADC */
+
+/** @} */
-- 
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