/* ChibiOS/GFX - Copyright (C) 2012 Joel Bodenmann aka Tectu 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 . */ /** * @file include/gadc/gadc.h * @brief GADC - Periodic ADC subsystem header file. * * @addtogroup GADC * * @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 { /** * @brief The type of this event (GEVENT_ADC) */ GEventType type; /** * @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) */ typedef void (*GADCCallbackFunction)(adcsample_t *buffer, void *param); /*===========================================================================*/ /* 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] countPerEvent The number of conversions to do before returning an event. * * @note If the high speed ADC is running it will be stopped. * @note Due to a bug 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 is likely to be 50Hz (although it might be * 100Hz on some hardware). * * @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 cannot be turned off. * @note The high speed ADC is capable of signalling via this method and a binary semaphore * at the same time. * * @api */ GSourceHandle gadcHighSpeedGetSource(void); #endif /** * @brief Allow retrieving of results from the high speed ADC using a Binary Semaphore and a static event buffer. * * @param[in] pbsem The binary 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. * @note The high speed ADC is capable of signalling via this method and the GEVENT * sub-system at the same time. * * @api */ void gadcHighSpeedSetBSem(BinarySemaphore *pbsem, GEventADC *pEvent); /** * @brief Start the high speed ADC conversions. * @pre It must have been initialised first with @p gadcHighSpeedInit() * * @api */ GSourceHandle 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. * * @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 gadcLowSpeedStart(uint32_t physdev, adcsample_t *buffer, GADCCallbackFunction fn, void *param); #ifdef __cplusplus } #endif #endif /* GFX_USE_GADC */ #endif /* _GADC_H */ /** @} */