logs archiveBotHelp.net / Freenode / #43oh / 2015 / August / 5 / 2
Spirilis
if you need it divided down further.... then you need to divide down the SMCLK to help it out
Amperture
and SMCLK is the one usually driving the various periphs like the Timer and USCI
Spirilis
yep
Amperture
Okay, now I'm feeling less like an as****e.
So when you say "terribly innacurate" in regard to the DCO and VLO.
Spirilis
well
DCO is reasonable
but drifts a bit by temperature I think
like +/-2% I think?
VLO is something like +/-30% I believe
averages 11000 ticks/second or maybe 10000 but with changes in temperature or voltage or whatever... look out
Amperture
One of my projects involves a--purely decorative, not necessary to be lab-accurate--RTC.
Spirilis
still, crystals and resonators command a much tighter tolerance than that
yeah, any RTC should use the LFXT1 with a watch crystal (tuning fork 32.768KHz XTAL)
MSP430 G2xxx series also has "software switchable" built in load capacitors for that which is cool
so it can be tuned slightly
Amperture
I was sitting here thinking I could get away with not using LFXT1, and running the timer off of DCO
Spirilis
even still, you'll notice it drifting by seconds a day or something
Amperture
To reduce cost and need to solder
Spirilis
it might work, but it won't be accurate
drifting by minutes a day I guess
Amperture
Makes me wish I could find (I feel like they must exist, I'm just not looking hard enough on digikey or mouser)
32kHz oscillators in the bigger through-hole can packages
Spirilis
Maxim DS3231 I2C RTC
Amperture
that you find 8MHz clocks coming in
Spirilis
Oscillator is built in
Addressable over I2C
well, this isn't through hole
but someone made a breakout for it called the ChronoDot that is through hole (it's a module)
expensive for what it is though
like $30 or some sh*t
anyway I used one of those in my wife's car with my first arduino project I did
it's highly accurate and 3 years later, still right on the minute
sitting in the trunk exposed to heat, freezing temps throughout the year
Amperture
Interesting
Spirilis
er nm, adafruit sells chronodot for $17.50
was thinking of the tilt compensated digital compass I bought from pololu :)
Amperture
http://www.ebay.com/itm/RTC-Real-Time-Clock-Memory-Module-For-Arduino-DS3231-AT24C32-IIC-Precision-/201263884692?hash=item2edc432994
Spirilis
it'll run off 3.3V too, in fact it comes with a coin cell battery holder for its battery backup
wow that's nice
haha $9.50 shipping
thought there was a catch :)
Amperture
http://www.ebay.com/itm/DS3231-AT24C32-IIC-module-precision-Real-time-clock-module-memory-module-Arduino-/400503978923?hash=item5d3fe5bbab $1.98 shipping
Spirilis
nice
if that is legit, it's a good way to roll
gotta check its power consumption though
that AT24C32 not sure how "low power" it is
if that matters
Amperture
Then you just have to hope and pray the chip isn't faked
Spirilis
yeah
and inaccurate as hell
the DS3231 from mouser et al isn't cheap anyhow, like $3+
Amperture
and frankly, even if it is, you can then buy the chip on its own, and you already have a breakout board
Spirilis
er no try $8+ in single qty
Amperture
oohhhhh
hmm
Spirilis
yeah I betcha that's fake but who knows
Amperture
I still like the idea of doing the RTC internally
Spirilis
I do know the TI Wolverine RTC_B has a trim feature so if you have a very accurate frequency counter you can tune it with that
(MSP430FR5969 et al)
still needs a 32.768KHz XTAL but tunable
yeah I mean if it works for you and you have support for "tuning" it in system... why not
probably good enough for a cheap joke
Amperture
It's just for a decorative clock, so accuracy isn't a big deal.
and I can put in tuning buttons.
cambazz
/quit
Spirilis
/ragequit
Amperture
android authority writing an article about the new PD USB-C chip
Am I crazy for noticing that the image they used in the lead (lede?) must be quite old?
http://www.androidauthority.com/texas-instruments-launches-usb-type-c-pd-controller-631245/
amstan
the one which says stellaris MCUs?
not sure
neat.. so they're saying all i need is that chip and it can give power from typeC?
that's pretty cool
3A of power essentially
doesn't do the smpsuing though
what if i want 5A of 5V?
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