332 lines
12 KiB
C
332 lines
12 KiB
C
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/**************************************************************************/
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/*!
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@file tsl2561.c
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@author K. Townsend (microBuilder.eu)
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@brief Drivers for the TAOS TSL2561 I2C digital luminosity sensor
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@section DESCRIPTION
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The TSL2561 is a 16-bit digital luminosity sensor the approximates
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the human eye's response to light. It contains one broadband
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photodiode that measures visible plus infrared light (channel 0)
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and one infrared photodiode (channel 1).
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@section EXAMPLE
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@code
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#include "drivers/sensors/tsl2561/tsl2561.h"
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...
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uint16_t broadband, ir;
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uint32_t lux;
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// Initialise luminosity sensor
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tsl2561Init();
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// Optional ... default setting is 400ms with no gain
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// Set timing to 101ms with no gain
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tsl2561SetTiming(TSL2561_INTEGRATIONTIME_101MS, TSL2561_GAIN_0X);
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// Check luminosity level and calculate lux
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tsl2561GetLuminosity(&broadband, &ir);
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lux = tsl2561CalculateLux(broadband, ir);
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printf("Broadband: %u, IR: %u, Lux: %d %s", broadband, ir, lux, CFG_PRINTF_NEWLINE);
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@endcode
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@section LICENSE
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Software License Agreement (BSD License)
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Copyright (c) 2010, microBuilder SARL
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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3. Neither the name of the copyright holders nor the
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names of its contributors may be used to endorse or promote products
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derived from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
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EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**************************************************************************/
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#include "tsl2561.h"
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static const uint32_t tsl2561_i2c_id = 0;
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static bool _tsl2561Initialised = 0;
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static tsl2561IntegrationTime_t _tsl2561IntegrationTime = TSL2561_INTEGRATIONTIME_402MS;
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static tsl2561Gain_t _tsl2561Gain = TSL2561_GAIN_0X;
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/**************************************************************************/
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/*!
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@brief Writes an 8 bit values over I2C
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*/
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/**************************************************************************/
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tsl2561Error_t tsl2561Write8 (uint8_t reg, uint8_t value)
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{
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platform_i2c_send_start(tsl2561_i2c_id);
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platform_i2c_send_address(tsl2561_i2c_id, TSL2561_ADDRESS, PLATFORM_I2C_DIRECTION_TRANSMITTER);
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platform_i2c_send_byte(tsl2561_i2c_id, reg);
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platform_i2c_send_byte(tsl2561_i2c_id, value);
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platform_i2c_send_stop(tsl2561_i2c_id);
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return TSL2561_ERROR_OK;
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}
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/**************************************************************************/
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/*!
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@brief Reads a 16 bit values over I2C
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*/
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/**************************************************************************/
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tsl2561Error_t tsl2561Read16(uint8_t reg, uint16_t *value)
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{
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platform_i2c_send_start(tsl2561_i2c_id);
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platform_i2c_send_address(tsl2561_i2c_id, TSL2561_ADDRESS, PLATFORM_I2C_DIRECTION_TRANSMITTER);
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platform_i2c_send_byte(tsl2561_i2c_id, reg);
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platform_i2c_send_stop(tsl2561_i2c_id);
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platform_i2c_send_start(tsl2561_i2c_id);
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platform_i2c_send_address(tsl2561_i2c_id, TSL2561_ADDRESS, PLATFORM_I2C_DIRECTION_RECEIVER);
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uint8_t ch_high = platform_i2c_recv_byte(tsl2561_i2c_id, 0);
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platform_i2c_send_stop(tsl2561_i2c_id);
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platform_i2c_send_start(tsl2561_i2c_id);
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platform_i2c_send_address(tsl2561_i2c_id, TSL2561_ADDRESS, PLATFORM_I2C_DIRECTION_TRANSMITTER);
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platform_i2c_send_byte(tsl2561_i2c_id, reg);
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platform_i2c_send_stop(tsl2561_i2c_id);
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platform_i2c_send_start(tsl2561_i2c_id);
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platform_i2c_send_address(tsl2561_i2c_id, TSL2561_ADDRESS, PLATFORM_I2C_DIRECTION_RECEIVER);
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uint8_t ch_low = platform_i2c_recv_byte(tsl2561_i2c_id, 0);
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platform_i2c_send_stop(tsl2561_i2c_id);
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// Shift values to create properly formed integer (low byte first)
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*value = (ch_low | (ch_high << 8));
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return TSL2561_ERROR_OK;
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}
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/**************************************************************************/
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/*!
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@brief Enables the device
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*/
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/**************************************************************************/
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tsl2561Error_t tsl2561Enable(void)
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{
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if (!_tsl2561Initialised) tsl2561Init();
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// Enable the device by setting the control bit to 0x03
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return tsl2561Write8(TSL2561_COMMAND_BIT | TSL2561_REGISTER_CONTROL, TSL2561_CONTROL_POWERON);
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}
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/**************************************************************************/
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/*!
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@brief Disables the device (putting it in lower power sleep mode)
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*/
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/**************************************************************************/
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tsl2561Error_t tsl2561Disable(void)
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{
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if (!_tsl2561Initialised) tsl2561Init();
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// Turn the device off to save power
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return tsl2561Write8(TSL2561_COMMAND_BIT | TSL2561_REGISTER_CONTROL, TSL2561_CONTROL_POWEROFF);
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}
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/**************************************************************************/
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/*!
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@brief Initialises the I2C block
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*/
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/**************************************************************************/
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tsl2561Error_t tsl2561Init(uint8_t sda, uint8_t scl)
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{
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// Initialise I2C
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platform_i2c_setup(tsl2561_i2c_id, sda, scl, PLATFORM_I2C_SPEED_SLOW);
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_tsl2561Initialised = 1;
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// Set default integration time and gain
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tsl2561SetTiming(_tsl2561IntegrationTime, _tsl2561Gain);
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// Note: by default, the device is in power down mode on bootup
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return TSL2561_ERROR_OK;
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}
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/**************************************************************************/
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/*!
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@brief Sets the integration time and gain (controls sensitivity)
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*/
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/**************************************************************************/
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tsl2561Error_t tsl2561SetTiming(tsl2561IntegrationTime_t integration, tsl2561Gain_t gain)
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{
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if (!_tsl2561Initialised) tsl2561Init();
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tsl2561Error_t error = TSL2561_ERROR_OK;
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// Enable the device by setting the control bit to 0x03
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error = tsl2561Enable();
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if (error) return error;
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// Turn the device off to save power
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error = tsl2561Write8(TSL2561_COMMAND_BIT | TSL2561_REGISTER_TIMING, integration | gain);
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if (error) return error;
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// Update value placeholders
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_tsl2561IntegrationTime = integration;
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_tsl2561Gain = gain;
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// Turn the device off to save power
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error = tsl2561Disable();
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if (error) return error;
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return error;
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}
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/**************************************************************************/
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/*!
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@brief Reads the luminosity on both channels from the TSL2561
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*/
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/**************************************************************************/
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tsl2561Error_t tsl2561GetLuminosity (uint16_t *broadband, uint16_t *ir)
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{
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if (!_tsl2561Initialised) tsl2561Init();
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tsl2561Error_t error = TSL2561_ERROR_OK;
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// Enable the device by setting the control bit to 0x03
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error = tsl2561Enable();
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if (error) return error;
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// Wait x ms for ADC to complete
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switch (_tsl2561IntegrationTime)
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{
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case TSL2561_INTEGRATIONTIME_13MS:
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systickDelay(14);
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break;
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case TSL2561_INTEGRATIONTIME_101MS:
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systickDelay(102);
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break;
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default:
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systickDelay(400);
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break;
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}
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// Reads two byte value from channel 0 (visible + infrared)
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error = tsl2561Read16(TSL2561_COMMAND_BIT | TSL2561_WORD_BIT | TSL2561_REGISTER_CHAN0_LOW, broadband);
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if (error) return error;
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// Reads two byte value from channel 1 (infrared)
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error = tsl2561Read16(TSL2561_COMMAND_BIT | TSL2561_WORD_BIT | TSL2561_REGISTER_CHAN1_LOW, ir);
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if (error) return error;
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// Turn the device off to save power
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error = tsl2561Disable();
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if (error) return error;
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return error;
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}
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/**************************************************************************/
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/*!
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@brief Calculates LUX from the supplied ch0 (broadband) and ch1
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(IR) readings
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*/
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/**************************************************************************/
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uint32_t tsl2561CalculateLux(uint16_t ch0, uint16_t ch1)
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{
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unsigned long chScale;
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unsigned long channel1;
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unsigned long channel0;
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switch (_tsl2561IntegrationTime)
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{
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case TSL2561_INTEGRATIONTIME_13MS:
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chScale = TSL2561_LUX_CHSCALE_TINT0;
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break;
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case TSL2561_INTEGRATIONTIME_101MS:
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chScale = TSL2561_LUX_CHSCALE_TINT1;
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break;
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default: // No scaling ... integration time = 402ms
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chScale = (1 << TSL2561_LUX_CHSCALE);
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break;
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}
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// Scale for gain (1x or 16x)
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if (!_tsl2561Gain) chScale = chScale << 4;
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// scale the channel values
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channel0 = (ch0 * chScale) >> TSL2561_LUX_CHSCALE;
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channel1 = (ch1 * chScale) >> TSL2561_LUX_CHSCALE;
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// find the ratio of the channel values (Channel1/Channel0)
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unsigned long ratio1 = 0;
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if (channel0 != 0) ratio1 = (channel1 << (TSL2561_LUX_RATIOSCALE+1)) / channel0;
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// round the ratio value
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unsigned long ratio = (ratio1 + 1) >> 1;
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unsigned int b, m;
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#ifdef TSL2561_PACKAGE_CS
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if ((ratio >= 0) && (ratio <= TSL2561_LUX_K1C))
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{b=TSL2561_LUX_B1C; m=TSL2561_LUX_M1C;}
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else if (ratio <= TSL2561_LUX_K2C)
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{b=TSL2561_LUX_B2C; m=TSL2561_LUX_M2C;}
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else if (ratio <= TSL2561_LUX_K3C)
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{b=TSL2561_LUX_B3C; m=TSL2561_LUX_M3C;}
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else if (ratio <= TSL2561_LUX_K4C)
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{b=TSL2561_LUX_B4C; m=TSL2561_LUX_M4C;}
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else if (ratio <= TSL2561_LUX_K5C)
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{b=TSL2561_LUX_B5C; m=TSL2561_LUX_M5C;}
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else if (ratio <= TSL2561_LUX_K6C)
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{b=TSL2561_LUX_B6C; m=TSL2561_LUX_M6C;}
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else if (ratio <= TSL2561_LUX_K7C)
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{b=TSL2561_LUX_B7C; m=TSL2561_LUX_M7C;}
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else if (ratio > TSL2561_LUX_K8C)
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{b=TSL2561_LUX_B8C; m=TSL2561_LUX_M8C;}
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#else
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if ((ratio >= 0) && (ratio <= TSL2561_LUX_K1T))
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{b=TSL2561_LUX_B1T; m=TSL2561_LUX_M1T;}
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else if (ratio <= TSL2561_LUX_K2T)
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{b=TSL2561_LUX_B2T; m=TSL2561_LUX_M2T;}
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else if (ratio <= TSL2561_LUX_K3T)
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{b=TSL2561_LUX_B3T; m=TSL2561_LUX_M3T;}
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else if (ratio <= TSL2561_LUX_K4T)
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{b=TSL2561_LUX_B4T; m=TSL2561_LUX_M4T;}
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else if (ratio <= TSL2561_LUX_K5T)
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{b=TSL2561_LUX_B5T; m=TSL2561_LUX_M5T;}
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else if (ratio <= TSL2561_LUX_K6T)
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{b=TSL2561_LUX_B6T; m=TSL2561_LUX_M6T;}
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else if (ratio <= TSL2561_LUX_K7T)
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{b=TSL2561_LUX_B7T; m=TSL2561_LUX_M7T;}
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else if (ratio > TSL2561_LUX_K8T)
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{b=TSL2561_LUX_B8T; m=TSL2561_LUX_M8T;}
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#endif
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unsigned long temp;
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temp = ((channel0 * b) - (channel1 * m));
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// do not allow negative lux value
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if (temp < 0) temp = 0;
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// round lsb (2^(LUX_SCALE-1))
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temp += (1 << (TSL2561_LUX_LUXSCALE-1));
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// strip off fractional portion
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uint32_t lux = temp >> TSL2561_LUX_LUXSCALE;
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// Signal I2C had no errors
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return lux;
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}
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