GADC implementation with demo program

Also includes driver for AT91SAM7 cpu

1 files changed, 190 insertions, 0 deletions

diff --git a/include/gadc/lld/gadc_lld.h b/include/gadc/lld/gadc_lld.h
new file mode 100644
index 00000000..f9cc8b47
--- /dev/null
+++ b/include/gadc/lld/gadc_lld.h
@@ -0,0 +1,190 @@
+/*
+    ChibiOS/GFX - Copyright (C) 2012, 2013
+                 Joel Bodenmann aka Tectu <joel@unormal.org>
+
+    This file is part of ChibiOS/GFX.
+
+    ChibiOS/GFX 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 3 of the License, or
+    (at your option) any later version.
+
+    ChibiOS/GFX 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, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * @file    include/gadc/lld/gadc_lld.h
+ * @brief   GADC - Periodic ADC driver header file.
+ *
+ * @defgroup Driver Driver
+ * @ingroup GADC
+ * @{
+ */
+
+#ifndef _GADC_LLD_H
+#define _GADC_LLD_H
+
+#include "gfx.h"
+
+#if GFX_USE_GADC || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Type definitions                                                          */
+/*===========================================================================*/
+
+/**
+ * @brief				The structure passed to start a timer conversion
+ * @note				We use the structure instead of parameters purely to save
+ * 						interrupt stack space which is very limited in some platforms.
+ * @{
+ */
+typedef struct GadcLldTimerData_t {
+	uint32_t		physdev;		/* @< A value passed to describe which physical ADC devices/channels to use. */
+	adcsample_t		*buffer;		/* @< The static buffer to put the ADC samples into. */
+	size_t			count;			/* @< The number of conversions to do before doing a callback and stopping the ADC. */
+	bool_t			now;			/* @< Trigger the first conversion now rather than waiting for the first timer interrupt (if possible) */
+	} GadcLldTimerData;
+/* @} */
+
+/**
+ * @brief				The structure passed to start a non-timer conversion
+ * @note				We use the structure instead of parameters purely to save
+ * 						interrupt stack space which is very limited in some platforms.
+ * @{
+ */
+typedef struct GadcLldNonTimerData_t {
+	uint32_t		physdev;		/* @< A value passed to describe which physical ADC devices/channels to use. */
+	adcsample_t		*buffer;		/* @< The static buffer to put the ADC samples into. */
+	} GadcLldNonTimerData;
+/* @} */
+
+/**
+ * @brief				These routines are the callbacks that the driver uses.
+ * @details				Defined in the high level GADC code.
+ *
+ * @notapi
+ * @{
+ */
+extern void GADC_ISR_CompleteI(ADCDriver *adcp, adcsample_t *buffer, size_t n);
+extern void GADC_ISR_ErrorI(ADCDriver *adcp, adcerror_t err);
+/**
+ * @}
+ */
+
+/**
+ * @brief				This can be incremented by the low level driver if a timer interrupt is missed.
+ * @details				Defined in the high level GADC code.
+ *
+ * @notapi
+ */
+extern volatile bool_t GADC_Timer_Missed;
+
+/*===========================================================================*/
+/* External declarations.                                                    */
+/*===========================================================================*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief				Initialise the driver
+ *
+ * @api
+ */
+void gadc_lld_init(void);
+
+/**
+ * @brief				Get the number of samples in a conversion.
+ * @details				Calculates and returns the number of samples per conversion for the specified physdev.
+ *
+ * @param[in] physdev		A value passed to describe which physical ADC devices/channels to use.
+ *
+ * @note				A physdev describing a mono device would return 1, a stereo device would return 2.
+ * 						For most ADC's physdev is a bitmap so it is only a matter of counting the bits.
+ *
+ * @api
+ */
+size_t gadc_lld_samples_per_conversion(uint32_t physdev);
+
+/**
+ * @brief				Start a periodic timer for high frequency conversions.
+ *
+ * @param[in] physdev		A value passed to describe which physical ADC devices/channels to use.
+ * @param[in] frequency		The frequency to create ADC conversions
+ *
+ * @note				The exact meaning of physdev is hardware dependent. It describes the channels
+ * 						the will be used later on when a "timer" conversion is actually scheduled.
+ * @note				It is assumed that the timer is capable of free-running even when the ADC
+ * 						is stopped or doing something else.
+ * @details				When a timer interrupt occurs a conversion should start if these is a "timer" conversion
+ * 						active.
+ * @note				If the ADC is stopped, doesn't have a "timer" conversion active or is currently executing
+ * 						a non-timer conversion then the interrupt can be ignored other than (optionally) incrementing
+ * 						the GADC_Timer_Missed variable.
+ *
+ * @api
+ */
+void gadc_lld_start_timer(uint32_t physdev, uint32_t frequency);
+
+/**
+ * @brief				Stop the periodic timer for high frequency conversions.
+ * @details				Also stops any current "timer" conversion (but not a current "non-timer" conversion).
+ *
+ * @param[in] physdev	A value passed to describe which physical ADC devices/channels in use.
+ *
+ * @note				The exact meaning of physdev is hardware dependent.
+ *
+ * @api
+ */
+void gadc_lld_stop_timer(uint32_t physdev);
+
+/**
+ * @brief				Start a "timer" conversion.
+ * @details				Starts a series of conversions triggered by the timer.
+ *
+ * @param[in] pgtd		Contains the parameters for the timer conversion.
+ *
+ * @note				The exact meaning of physdev is hardware dependent. It is likely described in the
+ * 						drivers gadc_lld_config.h
+ * @note				Some versions of ChibiOS actually call the callback function more than once, once
+ * 						at the half-way point and once on completion. The high level code handles this.
+ * @note				The driver should call @p GADC_ISR_CompleteI() when it completes the operation
+ * 						(or at the half-way point), or @p GAD_ISR_ErrorI() on an error.
+ * @note				The high level code ensures that this is not called while a non-timer conversion is in
+ * 						progress
+ *
+ * @iclass
+ */
+void gadc_lld_adc_timerI(GadcLldTimerData *pgtd);
+
+/**
+ * @brief				Start a "non-timer" conversion.
+ * @details				Starts a single conversion now.
+ *
+ * @param[in] pgntd		Contains the parameters for the non-timer conversion.
+ *
+ * @note				The exact meaning of physdev is hardware dependent. It is likely described in the
+ * 						drivers gadc_lld_config.h
+ * @note				The driver should call @p GADC_ISR_CompleteI() when it completes the operation
+ * 						or @p GAD_ISR_ErrorI() on an error.
+ * @note				The high level code ensures that this is not called while a timer conversion is in
+ * 						progress
+ *
+ * @iclass
+ */
+void gadc_lld_adc_nontimerI(GadcLldNonTimerData *pgntd);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GFX_USE_GADC */
+
+#endif /* _GADC_LLD_H */
+/** @} */