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rockbox/firmware/powermgmt.c
Heikki Hannikainen 9872b66cd1 Use average of two samples at both ends of the range for calculating smoother delta values. 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@1716 a1c6a512-1295-4272-9138-f99709370657
2002-08-13 16:06:29 +00:00

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Heikki Hannikainen
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "sh7034.h"
#include "kernel.h"
#include "thread.h"
#include "system.h"
#include "debug.h"
#include "panic.h"
#include "adc.h"
#include "string.h"
#include "sprintf.h"
#include "ata.h"
#include "power.h"
#include "powermgmt.h"
#ifdef SIMULATOR
int battery_level(void)
{
return 100;
}
bool battery_level_safe(void)
{
return true;
}
#else /* not SIMULATOR */
static char power_stack[DEFAULT_STACK_SIZE];
static char power_thread_name[] = "power";
unsigned short power_history[POWER_HISTORY_LEN];
#ifdef HAVE_CHARGE_CTRL
char power_message[POWER_MESSAGE_LEN] = "";
char charge_restart_level = CHARGE_RESTART_HI;
#endif
/* Returns battery level in percent */
int battery_level(void)
{
int level = 0;
int c = 0;
int i;
/* calculate average over last 3 minutes (skip empty samples) */
for (i = 0; i < 3; i++)
if (power_history[POWER_HISTORY_LEN-1-i]) {
level += power_history[POWER_HISTORY_LEN-1-i];
c++;
}
if (c)
level = level / c; /* avg */
else /* history was empty, get a fresh sample */
level = (adc_read(ADC_UNREG_POWER) * BATTERY_SCALE_FACTOR) / 10000;
if(level > BATTERY_LEVEL_FULL)
level = BATTERY_LEVEL_FULL;
if(level < BATTERY_LEVEL_EMPTY)
level = BATTERY_LEVEL_EMPTY;
return ((level-BATTERY_LEVEL_EMPTY) * 100) / BATTERY_RANGE;
}
/* Tells if the battery level is safe for disk writes */
bool battery_level_safe(void)
{
/* I'm pretty sure we don't want an average over a long time here */
if (power_history[POWER_HISTORY_LEN-1])
return power_history[POWER_HISTORY_LEN-1] > BATTERY_LEVEL_DANGEROUS;
else
return adc_read(ADC_UNREG_POWER) > (BATTERY_LEVEL_DANGEROUS * 10000) / BATTERY_SCALE_FACTOR;
}
/*
* This power thread maintains a history of battery voltage
* and implements a charging algorithm.
* Battery 'fullness' can be determined by the voltage drop, see:
*
* http://www.nimhbattery.com/nimhbattery-faq.htm questions 3 & 4
* http://www.powerpacks-uk.com/Charging%20NiMh%20Batteries.htm
* http://www.angelfire.com/electronic/hayles/charge1.html (soft start idea)
* http://www.powerstream.com/NiMH.htm (discouraging)
* http://www.panasonic.com/industrial/battery/oem/images/pdf/nimhchar.pdf
* http://www.duracell.com/oem/Pdf/others/nimh_5.pdf (discharging)
* http://www.duracell.com/oem/Pdf/others/nimh_6.pdf (charging)
*
* Charging logic which we're starting with (by Linus, Hes, Bagder):
*
* 1) max 16 hrs charge time (just in negative delta detection fails)
* 2) Stop at negative delta of 5 mins
* 3) Stop at 15 mins of zero-delta or below
* 4) minimum of 15 mins charge time before 2) is applied
* 5) after end of charging, wait for charge go down 80%
* before charging again if in 'no-use overnight charging mode'
* and down to 10% if in 'fixed-location mains-powered usage mode'
*/
static void power_thread(void)
{
int i;
int avg, ok_samples, spin_samples;
#ifdef HAVE_CHARGE_CTRL
int delta;
int charged_time = 0;
#endif
while (1)
{
/* Make POWER_AVG measurements and calculate an average of that to
* reduce the effect of backlights/disk spinning/other variation.
*/
ok_samples = spin_samples = avg = 0;
for (i = 0; i < POWER_AVG_N; i++) {
if (ata_disk_is_active()) {
if (!ok_samples) {
/* if we don't have any good non-disk-spinning samples,
* we take a sample anyway in case the disk is going
* to spin all the time.
*/
avg += adc_read(ADC_UNREG_POWER);
spin_samples++;
}
} else {
if (spin_samples) /* throw away disk-spinning samples */
spin_samples = avg = 0;
avg += adc_read(ADC_UNREG_POWER);
ok_samples++;
}
sleep(HZ*POWER_AVG_SLEEP);
}
avg = avg / ((ok_samples) ? ok_samples : spin_samples);
/* rotate the power history */
for (i = 0; i < POWER_HISTORY_LEN-1; i++)
power_history[i] = power_history[i+1];
/* insert new value in the end, in centivolts 8-) */
power_history[POWER_HISTORY_LEN-1] = (avg * BATTERY_SCALE_FACTOR) / 10000;
#ifdef HAVE_CHARGE_CTRL
if (charger_inserted()) {
if (charger_enabled) {
/* charger inserted and enabled */
charged_time++;
if (charged_time > CHARGE_MAX_TIME) {
DEBUGF("power: charged_time > CHARGE_MAX_TIME, enough!\n");
/* have charged too long and deltaV detection did not work! */
charger_enable(false);
snprintf(power_message, POWER_MESSAGE_LEN, "Chg tmout %d min", CHARGE_MAX_TIME);
/* Perhaps we should disable charging for several
hours from this point, just to be sure. */
} else {
if (charged_time > CHARGE_MIN_TIME) {
/* have charged continuously over the minimum charging time,
* so we monitor for deltaV going negative. Multiply things
* by 100 to get more accuracy without floating point arithmetic.
* power_history[] contains centivolts so after multiplying by 100
* the deltas are in tenths of millivolts (delta of 5 is
* 0.0005 V).
*/
delta = ( power_history[POWER_HISTORY_LEN-1] * 100
+ power_history[POWER_HISTORY_LEN-2] * 100
- power_history[POWER_HISTORY_LEN-1-CHARGE_END_NEGD+1] * 100
- power_history[POWER_HISTORY_LEN-1-CHARGE_END_NEGD] * 100 )
/ CHARGE_END_NEGD / 2;
if (delta < -100) { /* delta < -10 mV */
DEBUGF("power: short-term negative delta, enough!\n");
charger_enable(false);
snprintf(power_message, POWER_MESSAGE_LEN, "end negd %d %dmin", delta, charged_time);
} else {
/* if we didn't disable the charger in the previous test, check for low positive delta */
delta = ( power_history[POWER_HISTORY_LEN-1] * 100
+ power_history[POWER_HISTORY_LEN-2] * 100
- power_history[POWER_HISTORY_LEN-1-CHARGE_END_ZEROD+1] * 100
- power_history[POWER_HISTORY_LEN-1-CHARGE_END_ZEROD] * 100 )
/ CHARGE_END_ZEROD / 2;
if (delta < 1) { /* delta < 0.1 mV */
DEBUGF("power: long-term small positive delta, enough!\n");
charger_enable(false);
snprintf(power_message, POWER_MESSAGE_LEN, "end lowd %d %dmin", delta, charged_time);
}
}
}
}
} else {
/* charged inserted but not enabled */
/* if battery is not full, enable charging */
if (battery_level() < charge_restart_level) {
DEBUGF("power: charger inserted and battery not full, enabling\n");
charger_enable(true);
charged_time = 0;
snprintf(power_message, POWER_MESSAGE_LEN, "Chg started at %d%%", battery_level());
}
}
} else {
/* charger not inserted */
if (charger_enabled) {
/* charger not inserted but was enabled */
DEBUGF("power: charger disconnected, disabling\n");
charger_enable(false);
snprintf(power_message, POWER_MESSAGE_LEN, "Charger disc");
}
/* charger not inserted and disabled, so we're discharging */
}
#endif /* HAVE_CHARGE_CTRL*/
/* sleep for roughly a minute */
sleep(HZ*(60 - POWER_AVG_N * POWER_AVG_SLEEP));
}
}
void power_init(void)
{
/* init history to 0 */
memset(power_history, 0x00, sizeof(power_history));
#ifdef HAVE_CHARGE_CTRL
snprintf(power_message, POWER_MESSAGE_LEN, "Powermgmt started");
#endif
create_thread(power_thread, power_stack, sizeof(power_stack), power_thread_name);
}
#endif /* SIMULATOR */
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