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mkoswatte
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 Posted: Thu Nov 13, 2008 12:34 am Post subject: Implementing Real Time Clock in the ATmega128 |
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Hello I am new to Atmel
I am trying to make a data collecting device and send data over GPRS
but problem is I need to integrate real time clock calender in the device
to gather information when the data is collected?
There are two options
1.Use Atmega128 timer/clock
2.Use separate chip with clock calender
But i need to have separate battery powered system to keep the time up to
date
so what is the most soot-able way to keep accurate clock without any error
and low power consumption from above two?
Please reply with at least short answer if you know any!
Thanks!
Regard
Manula |
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Cesar Rabak
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| Posted: Thu Nov 13, 2008 12:47 am Post subject: Re: Implementing Real Time Clock in the ATmega128 |
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mkoswatte escreveu:
| Quote: | Hello I am new to Atmel
I am trying to make a data collecting device and send data over GPRS
but problem is I need to integrate real time clock calender in the device
to gather information when the data is collected?
There are two options
1.Use Atmega128 timer/clock
2.Use separate chip with clock calender
If you're going to use GPRS can't you get the time from the Operator? |
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Vladimir Vassilevsky
Guest
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| Posted: Thu Nov 13, 2008 1:01 am Post subject: Re: Implementing Real Time Clock in the ATmega128 |
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mkoswatte wrote:
| Quote: | Hello I am new to Atmel
I am trying to make a data collecting device and send data over GPRS
but problem is I need to integrate real time clock calender in the device
to gather information when the data is collected?
There are two options
1.Use Atmega128 timer/clock
2.Use separate chip with clock calender
But i need to have separate battery powered system to keep the time up to
date so what is the most soot-able way to keep accurate clock without any error
and low power consumption from above two?
|
If you are planning to keep the device in the low power sleep mode for a
long time, I wouldn't advise using the internal RTC of Atmega128. The
internal RTC consumption is somewhat 100 times higher than that of a
typical RTC chip. With the internal RTC, it wouldn't be practical to
operate from a coin cell.
Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com |
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MK
Guest
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| Posted: Thu Nov 13, 2008 8:36 am Post subject: Re: Implementing Real Time Clock in the ATmega128 |
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"Vladimir Vassilevsky" <antispam_bogus@hotmail.com> wrote in message
news:PJFSk.6322$x%.5195@nlpi070.nbdc.sbc.com...
| Quote: |
mkoswatte wrote:
Hello I am new to Atmel
I am trying to make a data collecting device and send data over GPRS
but problem is I need to integrate real time clock calender in the device
to gather information when the data is collected?
There are two options
1.Use Atmega128 timer/clock
2.Use separate chip with clock calender
But i need to have separate battery powered system to keep the time up to
date so what is the most soot-able way to keep accurate clock without
any error
and low power consumption from above two?
If you are planning to keep the device in the low power sleep mode for a
long time, I wouldn't advise using the internal RTC of Atmega128. The
internal RTC consumption is somewhat 100 times higher than that of a
typical RTC chip. With the internal RTC, it wouldn't be practical to
operate from a coin cell.
Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
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Vlad is right about the ATmega128 but the new parts are a bit better - the
Xmega series draws 650nA in RTC mode (average will be higher since the
processor will need to wake to service the clock). If you are new to Atmel
it might make sense to use one of the more modern parts (but do check
availability before you are committed to it !).
Michael Kellett |
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Frnak McKenney
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| Posted: Thu Nov 13, 2008 7:51 pm Post subject: Re: Implementing Real Time Clock in the ATmega128 |
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On Wed, 12 Nov 2008 12:34:48 -0600, mkoswatte <mkoswatte@yahoo.com> wrote:
| Quote: | Hello I am new to Atmel
I am trying to make a data collecting device and send data over GPRS
but problem is I need to integrate real time clock calender in the device
to gather information when the data is collected?
There are two options
1.Use Atmega128 timer/clock
2.Use separate chip with clock calender
But i need to have separate battery powered system to keep the time up to
date
so what is the most soot-able way to keep accurate clock without any error
and low power consumption from above two?
|
The DS1307 from Maxim/Dallas. It keeps a leap-year-compensated
calendar-clock, provides a small amount of NVRAM, and will
automatically switch to a backup power source (e.g. 3V coin cell)
when its primary power drops off.
http://www.maxim-ic.com/
There are other DS130x chips with different feature sets.
One caveat: don't leave the backup power pin unconnected. <grin!>
Enjoy...
--
Recessions are the market's way of teaching Americans Economics.
--
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney ayut mined spring dawt cahm (y'all) |
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mkoswatte
Guest
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| Posted: Sat Nov 15, 2008 4:29 pm Post subject: Re: Implementing Real Time Clock in the ATmega128 |
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| Quote: | If you're going to use GPRS can't you get the time from the Operator?
Oh Thanks Machan! for reminding me that.I have totally forget it |
do you think it is possible always to get the correct time from the
operator? is it reliable way of tracking time? |
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mkoswatte
Guest
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| Posted: Sat Nov 15, 2008 4:35 pm Post subject: Re: Implementing Real Time Clock in the ATmega128 |
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| Quote: |
mkoswatte wrote:
Hello I am new to Atmel
I am trying to make a data collecting device and send data over GPRS
but problem is I need to integrate real time clock calender in the
device
to gather information when the data is collected?
There are two options
1.Use Atmega128 timer/clock
2.Use separate chip with clock calender
But i need to have separate battery powered system to keep the time up
to
date so what is the most soot-able way to keep accurate clock without
any error
and low power consumption from above two?
If you are planning to keep the device in the low power sleep mode for a
long time, I wouldn't advise using the internal RTC of Atmega128. The
internal RTC consumption is somewhat 100 times higher than that of a
typical RTC chip. With the internal RTC, it wouldn't be practical to
operate from a coin cell.
Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
Thanks Vladimir! |
I also want to supply power from a coin cell I will try a RTC chip
can you tell me what should be the most sooitable features(Interfaces
I2C?) that the chip should have to easily communicate with Atmega 64/128. |
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Paul Keinanen
Guest
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| Posted: Sat Nov 15, 2008 4:46 pm Post subject: Re: Implementing Real Time Clock in the ATmega128 |
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On Sat, 15 Nov 2008 04:29:42 -0600, "mkoswatte" <mkoswatte@yahoo.com>
wrote:
| Quote: |
If you're going to use GPRS can't you get the time from the Operator?
Oh Thanks Machan! for reminding me that.I have totally forget it
do you think it is possible always to get the correct time from the
operator? is it reliable way of tracking time?
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This is usable as long as you can accept a second or two jitter in the
timing.
For instance NTP assumes that the propagation delay is the same in
both directions, which necessarily is not the case with GPRS.
Paul |
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mkoswatte
Guest
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| Posted: Sat Nov 15, 2008 7:15 pm Post subject: Re: Implementing Real Time Clock in the ATmega128 |
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| Quote: | On Sat, 15 Nov 2008 04:29:42 -0600, "mkoswatte" <mkoswatte@yahoo.com
wrote:
If you're going to use GPRS can't you get the time from the Operator?
Oh Thanks Machan! for reminding me that.I have totally forget it
do you think it is possible always to get the correct time from the
operator? is it reliable way of tracking time?
This is usable as long as you can accept a second or two jitter in the
timing.
For instance NTP assumes that the propagation delay is the same in
both directions, which necessarily is not the case with GPRS.
Paul
Thanks Paul!Your suggestion will be very very good! |
will tell what is happening next!
Regard Manula |
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