kopia lustrzana https://github.com/OpenRTX/OpenRTX
82 wiersze
3.3 KiB
C
82 wiersze
3.3 KiB
C
/***************************************************************************
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* Copyright (C) 2020 - 2022 by Federico Amedeo Izzo IU2NUO, *
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* Niccolò Izzo IU2KIN, *
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* Silvano Seva IU2KWO *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 3 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program; if not, see <http://www.gnu.org/licenses/> *
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***************************************************************************/
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#include <battery.h>
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#include <hwconfig.h>
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#include <math.h>
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/*
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* Minimum and maximum battery voltages expressed in fixed point Q8.8 format.
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* Obtained by multiplying the values in volt by 256.
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*/
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#if defined BAT_LIPO_1S
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static const uint16_t bat_v_min = 0x039C; // 3.61V
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static const uint16_t bat_v_max = 0x0426; // 4.15V
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#elif defined BAT_LIPO_2S
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static const uint16_t bat_v_min = 0x071A; // 7.10V
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static const uint16_t bat_v_max = 0x0819; // 8.10V
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#elif defined BAT_LIPO_3S
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static const uint16_t bat_v_min = 0x0AD4; // 10.83V
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static const uint16_t bat_v_max = 0x0C73; // 12.45V
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#elif defined BAT_NONE
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// Nothing to do, just avoid arising the compiler error
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#else
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#error Please define a battery type into platform/targets/.../hwconfig.h
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#endif
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uint8_t battery_getCharge(uint16_t vbat)
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{
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#ifdef BAT_NONE
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/* Return full charge if no battery is present. */
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(void) vbat;
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return 100;
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#else
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/*
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* Compute battery percentage by linear interpolation between zero and full
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* charge voltage values using Q8.8 fixed-point math to avoid using both
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* floating point and 64 bit variables, for maximum portability.
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*
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* Given that battery voltage parameter is an unsigned 16 bit value expressing
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* the voltage in mV, we first have to convert it to Q8.8 before computing
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* the charge percentage.
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*
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* Comparison between battery percentage computed using fixed point and
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* floating point routines on a voltage range from 10.83V to 12.45V with
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* increments of 1mV resulted in an average error of -0.015%, maximum error
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* of 0.79% and minimum error of -0.78%
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*/
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uint32_t vb = vbat << 16;
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vb = vb / 1000;
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vb = (vb + 256) >> 8;
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uint32_t diff = vb - bat_v_min;
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uint32_t range = bat_v_max - bat_v_min;
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uint32_t result = ((diff << 8) / range) * 100;
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result += 128;
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result >>= 8;
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if(result > 100) result = 100;
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return result;
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#endif
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}
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