69f4ffe686
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@17627 a1c6a512-1295-4272-9138-f99709370657
124 lines
4.3 KiB
C
124 lines
4.3 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2002 by Heikki Hannikainen, Uwe Freese
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* Revisions copyright (C) 2005 by Gerald Van Baren
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*
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* All files in this archive are subject to the GNU General Public License.
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* See the file COPYING in the source tree root for full license agreement.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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/* FIXME: This is just the Gigabeat F/X file with a different name... */
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#include "config.h"
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#include "adc.h"
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#include "powermgmt.h"
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/**
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* Fixed-point natural log
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* taken from http://www.quinapalus.com/efunc.html
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* "The code assumes integers are at least 32 bits long. The (positive)
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* argument and the result of the function are both expressed as fixed-point
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* values with 16 fractional bits, although intermediates are kept with 28
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* bits of precision to avoid loss of accuracy during shifts."
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*/
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static long flog(int x)
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{
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long t,y;
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y=0xa65af;
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if(x<0x00008000) x<<=16, y-=0xb1721;
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if(x<0x00800000) x<<= 8, y-=0x58b91;
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if(x<0x08000000) x<<= 4, y-=0x2c5c8;
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if(x<0x20000000) x<<= 2, y-=0x162e4;
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if(x<0x40000000) x<<= 1, y-=0x0b172;
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t=x+(x>>1); if((t&0x80000000)==0) x=t,y-=0x067cd;
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t=x+(x>>2); if((t&0x80000000)==0) x=t,y-=0x03920;
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t=x+(x>>3); if((t&0x80000000)==0) x=t,y-=0x01e27;
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t=x+(x>>4); if((t&0x80000000)==0) x=t,y-=0x00f85;
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t=x+(x>>5); if((t&0x80000000)==0) x=t,y-=0x007e1;
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t=x+(x>>6); if((t&0x80000000)==0) x=t,y-=0x003f8;
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t=x+(x>>7); if((t&0x80000000)==0) x=t,y-=0x001fe;
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x=0x80000000-x;
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y-=x>>15;
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return y;
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}
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const unsigned short battery_level_dangerous[BATTERY_TYPES_COUNT] =
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{
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3450
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};
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const unsigned short battery_level_shutoff[BATTERY_TYPES_COUNT] =
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{
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3400
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};
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/* voltages (millivolt) of 0%, 10%, ... 100% when charging disabled */
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const unsigned short percent_to_volt_discharge[BATTERY_TYPES_COUNT][11] =
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{
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/* Toshiba Gigabeat Li Ion 830mAH figured from discharge curve */
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{ 3480, 3550, 3590, 3610, 3630, 3650, 3700, 3760, 3800, 3910, 3990 },
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};
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/* voltages (millivolt) of 0%, 10%, ... 100% when charging enabled */
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const unsigned short percent_to_volt_charge[11] =
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{
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/* Toshiba Gigabeat Li Ion 830mAH */
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3480, 3550, 3590, 3610, 3630, 3650, 3700, 3760, 3800, 3910, 3990
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};
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/* Returns battery voltage from ADC [millivolts] */
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unsigned int battery_adc_voltage(void)
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{
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/* ADC reading 0-1023 = 2400mV-4700mV */
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return ((adc_read(ADC_BATTERY) * 2303) >> 10) + 2400;
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}
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/* Returns battery charge current from ADC [milliamps] */
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int battery_adc_charge_current(void)
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{
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/* Positive reading = charger to battery
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* Negative reading = battery to charger terminal
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* ADC reading -512-511 = -2875mA-2875mA */
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unsigned int value = adc_read(ADC_CHARGER_CURRENT);
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return (((int)value << 22) >> 22) * 2881 >> 9;
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}
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/* Returns battery temperature from ADC [deg-C] */
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unsigned int battery_adc_temp(void)
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{
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unsigned int value = adc_read(ADC_BATTERY_TEMP);
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/* E[volts] = value * 2.3V / 1023
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* R[ohms] = E/I = E[volts] / 0.00002[A] (Thermistor bias current source)
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*
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* Steinhart-Hart thermistor equation (sans "C*ln^2(R)" term because it
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* has negligible effect):
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* [A + B*ln(R) + D*ln^3(R)] = 1 / T[<5B>K]
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*
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* Coeffients that fit experimental data (one thermistor so far, one run):
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* A = 0.0013002631685462800
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* B = 0.0002000841932612330
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* D = 0.0000000640446750919
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*
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* Fixed-point output matches the floating-point version for each ADC
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* value.
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*/
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int R = 2070000 * value;
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long long ln = flog(R) + 83196;
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long long t0 = 425890304133ll;
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long long t1 = 1000000*ln;
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long long t3 = ln*ln*ln / 13418057;
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return ((32754211579494400ll / (t0 + t1 + t3)) - 27315) / 100;
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}
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