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authorJérémy Dufour2008-03-27 23:38:26 +0100
committerJérémy Dufour2008-03-27 23:38:26 +0100
commitf4d29f0c30e8af182de049f06ef3ef939f255309 (patch)
treeb2134ec498f4373e51deb99dca7600ce403e9bd6 /digital/io/src/sharp.c
parentcf45668e3f5f7c18954555185fde0d7906e610aa (diff)
* digital/io/src
- add sharp module with hysteresis support.
Diffstat (limited to 'digital/io/src/sharp.c')
-rw-r--r--digital/io/src/sharp.c162
1 files changed, 162 insertions, 0 deletions
diff --git a/digital/io/src/sharp.c b/digital/io/src/sharp.c
new file mode 100644
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+/* sharp.c */
+/* io - Input & Output with Artificial Intelligence (ai) support on AVR. {{{
+ *
+ * Copyright (C) 2008 Dufour Jrmy
+ *
+ * APBTeam:
+ * Web: http://apbteam.org/
+ * Email: team AT apbteam DOT org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * }}} */
+
+#include "sharp.h"
+
+#include "modules/adc/adc.h" /* ADC functions */
+#include "io.h"
+
+/**
+ * Cached array of raw sharp values.
+ */
+uint16_t sharp_values_[SHARP_NUMBER];
+
+/**
+ * Low (0 index) and high (1 index) thresholds for interpreted sharp values.
+ */
+uint16_t sharp_threshold[SHARP_NUMBER][2];
+
+/**
+ * Hysteresis.
+ */
+uint8_t sharp_hysteresis_[SHARP_NUMBER];
+
+/**
+ * Hysteresis threshold.
+ */
+#define SHARP_HYSTERESIS_THRESHOLD 3
+
+/**
+ * Previous sharp interpreted values.
+ */
+uint8_t sharp_previous_values_[SHARP_NUMBER];
+
+/* Initialize sharp module. */
+void
+sharp_init (void)
+{
+ /* Pins are in input mode by default */
+
+ /* ADC initialize */
+ adc_init ();
+}
+
+/* Update read data from sharps. */
+void
+sharp_update (uint8_t sharp_mask)
+{
+ uint8_t compt;
+
+ /* Go through the bit mask */
+ for (compt = 0; compt < SHARP_NUMBER; compt++)
+ {
+ /* Check if the bit/sharp id is set */
+ if (bit_is_set (sharp_mask, compt))
+ {
+ /* Start the capture */
+ adc_start (compt + 1);
+ /* Wait until ADC mesure is finished */
+ while (!adc_checkf ())
+ ;
+ /* Store the value */
+ sharp_values_[compt] = adc_read ();
+ }
+ }
+}
+
+/* Get raw cached data from sharps. */
+uint16_t
+sharp_get_raw (uint8_t sharp_id)
+{
+ /* Sanity check */
+ if (sharp_id < SHARP_NUMBER)
+ /* Return raw cached value */
+ return sharp_values_[sharp_id];
+ return 0;
+}
+
+/* Configure the thresholds of a sharp. */
+void
+sharp_set_threshold (uint8_t sharp_id, uint16_t low, uint16_t high)
+{
+ /* Sanity check */
+ if (sharp_id < SHARP_NUMBER)
+ {
+ /* Set low and high threshold */
+ sharp_threshold[sharp_id][0] = low;
+ sharp_threshold[sharp_id][1] = high;
+ }
+}
+
+/* Get interpreted value from sharps. */
+uint8_t
+sharp_get_interpreted (uint8_t sharp_id)
+{
+ uint8_t current_state;
+
+ /* Sanity check */
+ if (sharp_id < SHARP_NUMBER)
+ {
+ /* Check if sharp state is lower than the low threshold */
+ if (sharp_values_[sharp_id] < sharp_threshold[sharp_id][0])
+ /* Update current state seen by the sharp */
+ current_state = 0;
+ /* Check if sharp state is higher than the high threshold */
+ else if (sharp_values_[sharp_id] > sharp_threshold[sharp_id][1])
+ /* Update current state seen by the sharp */
+ current_state = 1;
+ /* In the middle */
+ else
+ /* Return the previous value */
+ return sharp_previous_values_[sharp_id];
+
+ /* Manage the hysteresis */
+ /* Check if previous value is the current state */
+ if (sharp_previous_values_[sharp_id] == current_state)
+ {
+ /* Reset hysteresis */
+ sharp_hysteresis_[sharp_id] = SHARP_HYSTERESIS_THRESHOLD;
+ /* Return current state */
+ return current_state;
+ }
+ /* Otherwise, check if this sharp value has been the same
+ * SHARP_HYSTERESIS_THRESHOLD times */
+ else if (sharp_hysteresis_[sharp_id]-- == 0)
+ {
+ /* Current value change (for SHARP_HYSTERESIS_THRESHOLD times)! */
+ /* Update previous value */
+ sharp_previous_values_[sharp_id] = current_state;
+ /* Reset hysteresis */
+ sharp_hysteresis_[sharp_id] = SHARP_HYSTERESIS_THRESHOLD;
+ /* Return current state */
+ return current_state;
+ }
+ else
+ /* Return previous state */
+ return sharp_previous_values_[sharp_id];
+ }
+ /* Error */
+ return 2;
+}