Rockbox Development > New Ports
SanDisk Sansa c200v2, m200v4, clipv1, clipv2, clip+, and fuzev2
bertrik:
I did a few battery runtime benches on my clip v1.
Somehow my clip v1 (1GB with FM) seems to get a lot longer runtime than those of other people.
I'm getting more than 8h with rockbox while other people seem to get only around 5h30.
I wonder what causes these runtime differences between people. I think it's not just a bad battery because people with low runtime in rockbox still seem to get normal runtimes in the OF.
* Could it be a difference in the Clip hardware perhaps? I do remember that some Clip v1s need the backlight voltage to be turned on while other work without it, for example.
* There's a number on the bottom of my Clip v1 (1GB with FM), saying BB0806AYJK. Perhaps this can be correlated to rockbox runtime.
* Or maybe we're neglecting to set some kind of power management setting?
To experiment a bit, I ran a benchmark with the CPU voltage regulator forced in a different mode: "direct length regulation" instead of auto (which probably chooses the "charge pump with length regulation" mode under light loads). With this change I got 5h48 runtime instead of 8h14, much closer to the result of other people.
saratoga:
Its possible we don't init some piece of hardware, and some clips default to different settings. I know with PP different PP devices would boot with random pieces of hardware enabled, resulting in different idle currents until we figured out how to turn them off. Something similar may be happening here.
matsch:
--- Quote from: bertrik on February 08, 2010, 12:59:14 PM ---I did a few battery runtime benches on my clip v1.
Somehow my clip v1 (1GB with FM) seems to get a lot longer runtime than those of other people.
I'm getting more than 8h with rockbox while other people seem to get only around 5h30.
To experiment a bit, I ran a benchmark with the CPU voltage regulator forced in a different mode: "direct length regulation" instead of auto (which probably chooses the "charge pump with length regulation" mode under light loads). With this change I got 5h48 runtime instead of 8h14, much closer to the result of other people.
--- End quote ---
There is bit 7 in AS314_CP_DCDC3_SETTING which defines a lower margin for changing to length regulator when setting to 1. In rockbox it is set to 0. Maybe there are some clips having a lower input voltage for the regulator. The voltage margin after the charge pump voltage divider is to low and they stay in length regulation. There is register IOVDDp in the as3525 data sheet. If it is set to 1 (2.99V) risk is higher for length regulator only.
FlynDice:
This is how I understand the charge pump/length regulation scheme. There are some charts in the datasheet graphing voltage vs current for both methods of regulation. The charge pump is the more efficient method to provide current but cannot maintain the voltage in the desired range at higher current draws. When the voltage drops too much it switches to length regulation to provide the needed current and maintain an acceptable voltage. So if you change the switching margin what you are doing is allowing the voltage to get lower before switching to length regulation. I don't know if that's OK or not... I checked on an almost empty battery and it was still running in charge pump mode.
FlynDice:
@ funman:
Here is the code I tested for clip+ dualboot: http://pastie.org/815858. It seems to work as far as branching to the OF when a button is pushed but there's something weird going on if there's no button pushed. It should just take an extra 4 secs then boot the of. Instead it just stays dark. I thought perhaps it was just the timer on the lcd but pushing a button won't wake the display. Interestingly, a normal power off pwr button press does power down normally. No need for the long power reset. I tried removing the last 4 sec delay and this was still happening.
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