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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/gadc.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 */
#define GADC_HSADC_RUNNING 0x0002 /**< @brief The High Speed ADC is currently running */
#define GADC_HSADC_GOTBUFFER 0x0004 /**< @brief A buffer is ready for processing */
#define GADC_HSADC_STALL 0x0008 /**< @brief The High Speed ADC has stalled due to no free buffers */
/** @} */
} 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)(void);
/*===========================================================================*/
/* 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
*
* @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 ChibiOS ONLY: Due to a bug in ChibiOS each buffer on the free-list must contain an even number of
* samples and for multi-channel devices it must hold a number of samples that is evenly divisible
* by 2 times the number of active channels.
* @note The physdev parameter may be used to turn on more than one ADC channel.
* Each channel is then interleaved into the provided buffer. Make sure your buffers all hold
* a number of samples evenly divisible by the number of active channels.
* As an example, if physdev turns on 2 devices then the buffer contains
* alternate device samples and the buffer must contain multiples of 2 samples.
* The exact meaning of physdev is hardware dependent.
* @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 100 samples/buffer, frequency = 5kHz) then the maximum
* frequency for low speed conversions will be 50Hz.
* @note Only a single sample format is supported - that provided by the GADC driver. That sample
* format applies to both high speed and low speed sampling.
*
* @api
*/
void gadcHighSpeedInit(uint32_t physdev, uint32_t frequency);
#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 blocked thread and the GEVENT
* sub-system at the same time.
*
* @api
*/
void gadcHighSpeedSetISRCallback(GADCISRCallbackFunction isrfn);
/**
* @brief Get a filled buffer from the ADC
* @return A GDataBuffer pointer or NULL if the timeout is exceeded
*
* @param[in] ms The maximum amount of time in milliseconds to wait for data if some is not currently available.
*
* @note After processing the data, your application must return the buffer to the free-list so that
* it can be used again. This can be done using @p gfxBufferRelease().
* @note A buffer may be returned to the free-list before you have finished processing it provided you finish
* processing it before GADC re-uses it. This is useful when RAM usage is critical to reduce the number
* of buffers required. It works before the free list is a FIFO queue and therefore buffers are kept
* in the queue as long as possible before they are re-used.
* @note The function ending with "I" is the interrupt class function.
* @api
* @{
*/
GDataBuffer *gadcHighSpeedGetData(delaytime_t ms);
GDataBuffer *gadcHighSpeedGetDataI(void);
/** @} */
/**
* @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 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 device stalling or 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 internal memory allocation fails
*
* @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 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 */
/** @} */
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