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authorinmarket <andrewh@inmarket.com.au>2014-02-19 00:36:52 +1000
committerinmarket <andrewh@inmarket.com.au>2014-02-19 00:36:52 +1000
commit37966ff16d923bbca53c9464815cb49cbd7fc3be (patch)
treed92db57067ffadd50cadf3ccf70efba3ac16e114 /src/gadc/sys_defs.h
parent1e131851d6732e22f055c893face6b473a26f111 (diff)
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Integrate the include files with each module. Simplifies structure of code.
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+/*
+ * This file is subject to the terms of the GFX License. If a copy of
+ * the license was not distributed with this file, you can obtain one at:
+ *
+ * http://ugfx.org/license.html
+ */
+
+/**
+ * @file src/gadc/sys_defs.h
+ *
+ * @addtogroup GADC
+ *
+ * @brief Module to abstract the very variable ADC interfaces of the underlying systems
+ *
+ * @details The reason why ChibiOS/GFX has it's own ADC abstraction is because
+ * the Chibi-OS drivers are very CPU specific and do not
+ * provide a way across all hardware platforms to create periodic
+ * ADC conversions. There are also issues with devices with different
+ * characteristics or periodic requirements on the same ADC
+ * device (but different channels). This layer attempts to solve these
+ * problems to provide a architecture neutral API. It also provides extra
+ * features such as multi-buffer chaining for high speed ADC sources.
+ * It provides one high speed virtual ADC device (eg a microphone) and
+ * numerous low speed (less than 100Hz) virtual ADC devices (eg dials,
+ * temperature sensors etc). The high speed device has timer based polling
+ * to ensure exact conversion periods and a buffer management system.
+ * The low speed devices are assumed to be non-critical timing devices
+ * and do not have any buffer management.
+ * Note that while only one high speed device has been provided it can
+ * be used to read multiple physical ADC channels on the one physical
+ * ADC device.
+ * All callback routines are thread based unlike the Chibi-OS interrupt based
+ * routines.
+ *
+ * @{
+ */
+
+#ifndef _GADC_H
+#define _GADC_H
+
+#include "gfx.h"
+
+#if GFX_USE_GADC || defined(__DOXYGEN__)
+
+/* Include the driver defines */
+#include "gadc_lld_config.h"
+
+/*===========================================================================*/
+/* Type definitions */
+/*===========================================================================*/
+
+// Event types for GADC
+#define GEVENT_ADC (GEVENT_GADC_FIRST+0)
+
+/**
+ * @brief The High Speed ADC event structure.
+ * @{
+ */
+typedef struct GEventADC_t {
+ #if GFX_USE_GEVENT || defined(__DOXYGEN__)
+ /**
+ * @brief The type of this event (GEVENT_ADC)
+ */
+ GEventType type;
+ #endif
+
+ /**
+ * @brief The event flags
+ */
+ uint16_t flags;
+ /**
+ * @brief The event flag values.
+ * @{
+ */
+ #define GADC_HSADC_LOSTEVENT 0x0001 /**< @brief The last GEVENT_HSDADC event was lost */
+ /** @} */
+ /**
+ * @brief The number of conversions in the buffer
+ */
+ size_t count;
+ /**
+ * @brief The buffer containing the conversion samples
+ */
+ adcsample_t *buffer;
+} GEventADC;
+/** @} */
+
+/**
+ * @brief A callback function (executed in a thread context) for a low speed conversion
+ */
+typedef void (*GADCCallbackFunction)(adcsample_t *buffer, void *param);
+
+/**
+ * @brief A callback function (executed in an ISR context) for a high speed conversion
+ */
+typedef void (*GADCISRCallbackFunction)(adcsample_t *buffer, size_t size);
+
+/*===========================================================================*/
+/* External declarations. */
+/*===========================================================================*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Initialise the high speed ADC.
+ * @details Initialises but does not start the 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
+ * @param[in] buffer The static buffer to put the ADC samples into.
+ * @param[in] bufcount The total number of conversions that will fit in the buffer.
+ * @param[in] samplesPerEvent The number of conversions to do before returning an event.
+ *
+ * @note If the high speed ADC is running it will be stopped. The Event subsystem is
+ * disconnected from the high speed ADC and any binary semaphore event is forgotten.
+ * @note bufcount must be greater than countPerEvent (usually 2 or more times) otherwise
+ * the buffer will be overwritten with new data while the application is still trying
+ * to process the old data.
+ * @note Due to a bug/feature in Chibi-OS countPerEvent must be even. If bufcount is not
+ * evenly divisable by countPerEvent, the remainder must also be even.
+ * @note The physdev parameter may be used to turn on more than one ADC channel.
+ * Each channel is then interleaved into the provided buffer. Note 'bufcount'
+ * and 'countPerEvent' parameters describe the number of conversions not the
+ * number of samples.
+ * As an example, if physdev turns on 2 devices then the buffer contains
+ * alternate device samples and the buffer must contain 2 * bufcount samples.
+ * The exact meaning of physdev is hardware dependent.
+ * @note The buffer is circular. When the end of the buffer is reached it will start
+ * putting data into the beginning of the buffer again.
+ * @note The event listener must process the event (and the data in it) before the
+ * next event occurs. If not, the following event will be lost.
+ * @note If bufcount is evenly divisable by countPerEvent, then every event will return
+ * countPerEvent conversions. If bufcount is not evenly divisable, it will return
+ * a block of samples containing less than countPerEvent samples when it reaches the
+ * end of the buffer.
+ * @note While the high speed ADC is running, low speed conversions can only occur at
+ * the frequency of the high speed events. Thus if high speed events are
+ * being created at 50Hz (eg countPerEvent = 100, frequency = 5kHz) then the maximum
+ * frequency for low speed conversions will be 50Hz.
+ *
+ * @api
+ */
+void gadcHighSpeedInit(uint32_t physdev, uint32_t frequency, adcsample_t *buffer, size_t bufcount, size_t samplesPerEvent);
+
+#if GFX_USE_GEVENT || defined(__DOXYGEN__)
+ /**
+ * @brief Turn on sending results to the GEVENT sub-system.
+ * @details Returns a GSourceHandle to listen for GEVENT_ADC events.
+ *
+ * @note The high speed ADC will not use the GEVENT system unless this is
+ * called first. This saves processing time if the application does
+ * not want to use the GEVENT sub-system for the high speed ADC.
+ * Once turned on it can only be turned off by calling @p gadcHighSpeedInit() again.
+ * @note The high speed ADC is capable of signalling via this method, an ISR callback and a
+ * binary semaphore at the same time.
+ *
+ * @return The GSourceHandle
+ *
+ * @api
+ */
+ GSourceHandle gadcHighSpeedGetSource(void);
+#endif
+
+/**
+ * @brief Allow retrieving of results from the high speed ADC using an ISR callback.
+ *
+ * @param[in] isrfn The callback function (called in an ISR context).
+ *
+ * @note Passing a NULL for isrfn will turn off signalling via this method as will calling
+ * @p gadcHighSpeedInit().
+ * @note The high speed ADC is capable of signalling via this method, a binary semaphore and the GEVENT
+ * sub-system at the same time.
+ *
+ * @api
+ */
+void gadcHighSpeedSetISRCallback(GADCISRCallbackFunction isrfn);
+
+/**
+ * @brief Allow retrieving of results from the high speed ADC using a Binary Semaphore and a static event buffer.
+ *
+ * @param[in] pbsem The semaphore is signaled when data is available.
+ * @param[in] pEvent The static event buffer to place the result information.
+ *
+ * @note Passing a NULL for pbsem or pEvent will turn off signalling via this method as will calling
+ * @p gadcHighSpeedInit().
+ * @note The high speed ADC is capable of signalling via this method, an ISR callback and the GEVENT
+ * sub-system at the same time.
+ *
+ * @api
+ */
+void gadcHighSpeedSetBSem(gfxSem *pbsem, GEventADC *pEvent);
+
+/**
+ * @brief Start the high speed ADC conversions.
+ * @pre It must have been initialised first with @p gadcHighSpeedInit()
+ *
+ * @api
+ */
+void gadcHighSpeedStart(void);
+
+/**
+ * @brief Stop the high speed ADC conversions.
+ *
+ * @api
+ */
+void gadcHighSpeedStop(void);
+
+/**
+ * @brief Perform a single low speed ADC conversion
+ * @details Blocks until the conversion is complete
+ * @pre This should not be called from within a GTimer callback as this routine
+ * blocks until the conversion is ready.
+ *
+ * @param[in] physdev A value passed to describe which physical ADC devices/channels to use.
+ * @param[in] buffer The static buffer to put the ADC samples into.
+ *
+ * @note This may take a while to complete if the high speed ADC is running as the
+ * conversion is interleaved with the high speed ADC conversions on a buffer
+ * completion.
+ * @note The result buffer must be large enough to store one sample per device
+ * described by the 'physdev' parameter.
+ * @note If calling this routine would exceed @p GADC_MAX_LOWSPEED_DEVICES simultaneous low
+ * speed devices, the routine will wait for an available slot to complete the
+ * conversion.
+ * @note Specifying more than one device in physdev is possible but discouraged as the
+ * calculations to ensure the high speed ADC correctness will be incorrect. Symptoms
+ * from over-running the high speed ADC include high speed samples being lost.
+ *
+ * @api
+ */
+void gadcLowSpeedGet(uint32_t physdev, adcsample_t *buffer);
+
+/**
+ * @brief Perform a low speed ADC conversion with callback (in a thread context)
+ * @details Returns FALSE if there are no free low speed ADC slots. See @p GADC_MAX_LOWSPEED_DEVICES for details.
+ *
+ * @param[in] physdev A value passed to describe which physical ADC devices/channels to use.
+ * @param[in] buffer The static buffer to put the ADC samples into.
+ * @param[in] fn The callback function to call when the conversion is complete.
+ * @param[in] param A parameter to pass to the callback function.
+ *
+ * @return FALSE if no free low speed ADC slots.
+ *
+ * @note This may be safely called from within a GTimer callback.
+ * @note The callback may take a while to occur if the high speed ADC is running as the
+ * conversion is interleaved with the high speed ADC conversions on a buffer
+ * completion.
+ * @note The result buffer must be large enough to store one sample per device
+ * described by the 'physdev' parameter.
+ * @note As this routine uses a low speed ADC, it asserts if you try to run more than @p GADC_MAX_LOWSPEED_DEVICES
+ * at the same time.
+ * @note Specifying more than one device in physdev is possible but discouraged as the
+ * calculations to ensure the high speed ADC correctness will be incorrect. Symptoms
+ * from over-running the high speed ADC include high speed samples being lost.
+ *
+ * @api
+ */
+bool_t gadcLowSpeedStart(uint32_t physdev, adcsample_t *buffer, GADCCallbackFunction fn, void *param);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GFX_USE_GADC */
+
+#endif /* _GADC_H */
+/** @} */
+