/*
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/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 {
#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)
*/
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. 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 overwitten with new data while the application is still trying
* to process the old data.
* @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 can only be turned off by calling @p gadcHighSpeedInit() again.
* @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 as will calling
* @p gadcHighSpeedInit().
* @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
*/
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.
*
* @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 */
/** @} */