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rockbox/firmware/powermgmt.c
Heikki Hannikainen a4cb4aff7b Tune charging algorithm: use more voltage samples (4 per minute) and discard 
samples taken while the disk is spinning. If no 'disk idle' samples are
available, use the ones we have anyway (yeah, maybe we could interpolate too).
Also tuned the deltas detection too, and fixed some comments. This seems to
work quite a bit better for me.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@1682 a1c6a512-1295-4272-9138-f99709370657
2002-08-12 12:19:25 +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-1-CHARGE_END_NEGD] * 100 )
/ CHARGE_END_NEGD;
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-1-CHARGE_END_ZEROD] * 100 )
/ CHARGE_END_ZEROD;
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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