Hi all.

Yet another request for help in the selection of an appropriate uC.

I would like to construct a data logger. This data logger may be
located in areas remote from power and human kind. It will read 1-Wire
interfaced weather instruments at an interval of 2 seconds and store
the weather data over an extended period of time, such as a year. The
weather data acquired should be stored with the date and time. The
stored data will have to be transferred to a PC at some point. The
requirements for such a data logger would be:
1. Very small power consumption. It would be nice if the uC would be
capable of operating from the merest suggestion of a hint of a
picowatt :)
2. A 1-Wire interface would be nice. This would make the development
process easier.
3. The ability to store perhaps 2GB of data. I believe this would
require the means to either write/read a MMC/SD card or a USB memory
device (a memory stick, I believe these are called). It would be nice
if the uC had the capability to access the MMC/SD or USB directly
although using one of the more common uC interfaces (e.g. SPI) is
probably all that can be expected.
4. PROM - I do not know what size the program will be - yet.
5. RAM - I think writing to MMC/SD/USB memory is probably more
efficient in blocks of, say, 512 or 1024 bytes. Therefore there should
be enough RAM to store at least 512 bytes of the data to be logged in
addition to the RAM required for normal temporary storage. So, I guess
the minimum should be at least 1.5k. If I wish to read back the data
written for verification purposes then that would probably increase to
2k.
6. The ability to transfer the stored data to a PC. If a USB memory
device (stick) is used then this is already addressed, assuming that
FAT is used. If MMC/SD then an appropriate reader could be used  - but
this would push up the overall cost. An alternative might be to have
some form of high speed data transfer mechanism, e.g. 10/100/1000
ethernet or possibly a USB port for communication with the PC. A
standard serial connection running at a sustained rate of 115k baud
would take 48 hours to transfer 2GB, if I did the calculations
correctly - a 10Mb connection 33 minutes, I think.
7. A real time clock
8. Some mechanism to configure the device - for example the date and
time; this could be via a PC link or perhaps the use of on-board
switches and an LCD. If switches/LCD then the ability to drive an LCD
would be required. If a PC link then perhaps an RS232 interface, or
the use of the previously mentioned USB/Ethernet interfaces (but this
could perhaps make things a tad more complicated than they need to
be). Of course, I could provide both an on-board mechanism to
configure the device and a PC link.
9. Reasonable overall cost.
10. The availability of evaluation boards at perhaps $100 or less.
11. Free or cheap development tools

12. In addition to the above. I would prefer not to purchase any
device that is made in a part of the world that does not treat its
people well, if that is possible.

About me...
I have discovered that the best way to learn a subject is to give
oneself a project that is of real use - hence the above. I studied
electronics in college in the early '80s. There, we did some work with
the Intel 8085 and the Rockwell 6502. We used machine code and
assembler with the 8085 and basic with the Rockwell device. RS232 did
exist at that time, but USB, SPI, etc did not and I will have to learn
what I will need to know about any of these that I might use. I have
little knowledge about ethernet. I have had a long-term desire to
pursue this field (uCs) but not the resources, particularly the time,
until now. I taught myself C - I havn't been the same since :) - in
the early '90s, but have not had much use of it since.

I do understand that uC selection is usually a compromise of the
features available versus those required.

Perhaps some of you will know of a uC that fits the bill, or comes
close.
This is not urgent. I do not plan to start this project for a few
months, but I would like to make use of the time to conduct research.
I believe the most important decision that I need to make is which uC
to use.

Thank you all.
Take care.

On May 3, 10:51 am, AC Me <mmal...@gofree.indigo.ie> wrote:
> Hi all.
>
> Yet another request for help in the selection of an appropriate uC.
>
> I would like to construct a data logger. This data logger may be
> located in areas remote from power and human kind. It will read 1-Wire
> interfaced weather instruments at an interval of 2 seconds and store
> the weather data over an extended period of time, such as a year. The
> weather data acquired should be stored with the date and time. The
> stored data will have to be transferred to a PC at some point. The
> requirements for such a data logger would be:
> 1. Very small power consumption. It would be nice if the uC would be
> capable of operating from the merest suggestion of a hint of a
> picowatt :)

If you put the uC in standby between readings, it can extend battery
life substantially.  For example, our custom chip run at 800uA and
standby at 80uA.  It can run standby for 100 days and forever with a
small solar cell.

> 4. PROM - I do not know what size the program will be - yet.

We have 16K One Time Programmable PROM.

> 7. A real time clock

Yes.

> 8. Some mechanism to configure the device - for example the date and
> time; this could be via a PC link or perhaps the use of on-board
> switches and an LCD. If switches/LCD then the ability to drive an LCD
> would be required.

Yes, we have LCD driver (up to 12 segments and 4 commons)

> 9. Reasonable overall cost.

50 cents for the uC.

> 10. The availability of evaluation boards at perhaps $100 or less.

5 dollars for the evaluation board.

> 11. Free or cheap development tools

Yes, free C compiler.

>
> About me...
> I have discovered that the best way to learn a subject is to give
> oneself a project that is of real use - hence the above. I studied
> electronics in college in the early '80s. There, we did some work with
> the Intel 8085 and the Rockwell 6502.

Yes, it's a 6502 core in a 32 pins QFP (5mm x 5mm)

AC Me wrote:

> I would like to construct a data logger. This data logger may be
> located in areas remote from power and human kind. It will read 1-Wire
> interfaced weather instruments at an interval of 2 seconds and store
> the weather data over an extended period of time, such as a year.

That's not going to be cheap.  You're talking about several tens of 
megabytes of data there!

> The
> weather data acquired should be stored with the date and time. 

That's at least 3 bytes for the time-stamp alone, and you would be 
storing 15 million samples per year.  That makes 45 MB before you've 
stored the first bit of actual payload data.

> 1. Very small power consumption. It would be nice if the uC would be
> capable of operating from the merest suggestion of a hint of a
> picowatt :)

> 2. A 1-Wire interface would be nice. This would make the development
> process easier.

I'm afraid that combination is flat-out impossible.  The 1-wire protocol 
itself burns a lot more than a pico-watt on average, what with the line 
drivers fighting against the pull-up resistor every bit of the way.

> 3. The ability to store perhaps 2GB of data. I believe this would
> require the means to either write/read a MMC/SD card or a USB memory
> device (a memory stick, I believe these are called).

A micro with a USB host implementation would be way beyond your power 
budget.  Writing flash is in itself quite an energy-consuming operation.

> 6. The ability to transfer the stored data to a PC. If a USB memory
> device (stick) is used then this is already addressed, assuming that
> FAT is used. If MMC/SD then an appropriate reader could be used  - but
> this would push up the overall cost. An alternative might be to have
> some form of high speed data transfer mechanism, e.g. 10/100/1000
> ethernet or possibly a USB port for communication with the PC.

No, those wouldn't be alternatives, cost-wise, to a simple memory card 
reader for the PC to be equipped with.  Those are on the order of 10$ a 
pop, retail.

On May 3, 11:41 am, Hans-Bernhard Br=F6ker <HBBroe...@t-online.de>
wrote:
> AC Me wrote:
> > I would like to construct a data logger. This data logger may be
> > located in areas remote from power and human kind. It will read 1-Wire
> > interfaced weather instruments at an interval of 2 seconds and store
> > the weather data over an extended period of time, such as a year.
>
> That's not going to be cheap.  You're talking about several tens of
> megabytes of data there!
>
> > The
> > weather data acquired should be stored with the date and time.
>
> That's at least 3 bytes for the time-stamp alone, and you would be
> storing 15 million samples per year.  That makes 45 MB before you've
> stored the first bit of actual payload data.

A 45MB compact flash is less than $1, if you can still find it so
small.
A couple of Gs are reasonable in price too.

>  Writing flash is in itself quite an energy-consuming operation.

But you can buffer the data and only write every few minutes.

The response (trimmed) below, sounds great, but who is "We" mentioned 
just before item 7 below? I checked 'linnix.info-for.us' but that URL
is 'Parked'. So where do I go to check out this '6502 core' uP?
At this price, I'm ready to order! Thanks. 

On Sat, 03 May 2008 11:21:44 -0700, linnix wrote:

> On May 3, 10:51 am, AC Me <mmal...@gofree.indigo.ie> wrote:
>> Hi all.
>>
>> Yet another request for help in the selection of an appropriate uC.
(snip)
> 
> We have 16K One Time Programmable PROM.
> 
>> 7. A real time clock
> 
> Yes.
> 
>> 8. Some mechanism to configure the device - for example the date and
>> time; this could be via a PC link or perhaps the use of on-board
>> switches and an LCD. If switches/LCD then the ability to drive an LCD
>> would be required.
> 
> Yes, we have LCD driver (up to 12 segments and 4 commons)
> 
>> 9. Reasonable overall cost.
> 
> 50 cents for the uC.
> 
>> 10. The availability of evaluation boards at perhaps $100 or less.
> 
> 5 dollars for the evaluation board.
> 
>> 11. Free or cheap development tools
> 
> Yes, free C compiler.
> 
> 
>> About me...
>> I have discovered that the best way to learn a subject is to give
>> oneself a project that is of real use - hence the above. I studied
>> electronics in college in the early '80s. There, we did some work with
>> the Intel 8085 and the Rockwell 6502.
> 
> Yes, it's a 6502 core in a 32 pins QFP (5mm x 5mm)

On May 3, 12:45 pm, Roland Latour <bo...@bogus.com> wrote:
> The response (trimmed) below, sounds great, but who is "We" mentioned
> just before item 7 below? I checked 'linnix.info-for.us' but that URL
> is 'Parked'. So where do I go to check out this '6502 core' uP?
> At this price, I'm ready to order! Thanks.

The initial batch is being die-bonded at the moment, but we should
have them ready in a couple of week.  The chip spec is at:

http://san-tech-lcd.info/proto/

There is a web contact form at the bottom.

>
>
>
> On Sat, 03 May 2008 11:21:44 -0700, linnix wrote:
> > On May 3, 10:51 am, AC Me <mmal...@gofree.indigo.ie> wrote:
> >> Hi all.
>
> >> Yet another request for help in the selection of an appropriate uC.
> (snip)
>
> > We have 16K One Time Programmable PROM.
>
> >> 7. A real time clock
>
> > Yes.
>
> >> 8. Some mechanism to configure the device - for example the date and
> >> time; this could be via a PC link or perhaps the use of on-board
> >> switches and an LCD. If switches/LCD then the ability to drive an LCD
> >> would be required.
>
> > Yes, we have LCD driver (up to 12 segments and 4 commons)
>
> >> 9. Reasonable overall cost.
>
> > 50 cents for the uC.
>
> >> 10. The availability of evaluation boards at perhaps $100 or less.
>
> > 5 dollars for the evaluation board.
>
> >> 11. Free or cheap development tools
>
> > Yes, free C compiler.
>
> >> About me...
> >> I have discovered that the best way to learn a subject is to give
> >> oneself a project that is of real use - hence the above. I studied
> >> electronics in college in the early '80s. There, we did some work with
> >> the Intel 8085 and the Rockwell 6502.
>
> > Yes, it's a 6502 core in a 32 pins QFP (5mm x 5mm)

linnix wrote:
> On May 3, 11:41 am, Hans-Bernhard Bröker <HBBroe...@t-online.de>
> wrote:
>> AC Me wrote:
>>> I would like to construct a data logger. This data logger may be
>>> located in areas remote from power and human kind. It will read 1-Wire
>>> interfaced weather instruments at an interval of 2 seconds and store
>>> the weather data over an extended period of time, such as a year.
>> That's not going to be cheap.  You're talking about several tens of
>> megabytes of data there!
>>
>>> The
>>> weather data acquired should be stored with the date and time.
>> That's at least 3 bytes for the time-stamp alone, and you would be
>> storing 15 million samples per year.  That makes 45 MB before you've
>> stored the first bit of actual payload data.
> 
> A 45MB compact flash is less than $1, if you can still find it so
> small.
> A couple of Gs are reasonable in price too.
> 
>>  Writing flash is in itself quite an energy-consuming operation.
> 
> But you can buffer the data and only write every few minutes.
> 
Sure it is possible.  But as a beginners project?  What is you power 
budget? How many what hours is the protect?  Many small MCUs can do the 
job PIC, AVR, MP430.  None can talk to a USB Stick without another chip. 
  This should kill you power budget.  None have a 1-wire interface.  I 
am not sure any thing does.
What do you know, any software or hardware?  ASM, C, Basic?

linnix wrote:
> On May 3, 12:45 pm, Roland Latour <bo...@bogus.com> wrote:
> 
>>The response (trimmed) below, sounds great, but who is "We" mentioned
>>just before item 7 below? I checked 'linnix.info-for.us' but that URL
>>is 'Parked'. So where do I go to check out this '6502 core' uP?
>>At this price, I'm ready to order! Thanks.
> 
> 
> The initial batch is being die-bonded at the moment, but we should
> have them ready in a couple of week.  The chip spec is at:
> 
> http://san-tech-lcd.info/proto/
> 
>>>16K One Time Programmable PROM.
>>>A real time clock
>>>LCD driver (up to 12 segments and 4 commons)
>>>50 cents for the uC.
>>>5 dollars for the evaluation board.
>>>free C compiler.
>>>6502 core in a 32 pins QFP (5mm x 5mm)

Interesting looking device.

What volumes is the 50c price point for ?
is that price for the die, or the tested/packaged device ?

With OTP, what yields do you expect ? (as you cannot test the OTP)

What debug pathway is there for this device ?

SST had a Flash 28p Device with a 6502 core, called the SST65P542R,
which targeted remote control. The 2001 data sheet can still be found,
but the chip seems to no longer exist.

-jg

On May 3, 7:41=A0pm, Hans-Bernhard Br=F6ker <HBBroe...@t-online.de> wrote:
> AC Me wrote:
> > I would like to construct a data logger. This data logger may be
> > located in areas remote from power and human kind. It will read 1-Wire
> > interfaced weather instruments at an interval of 2 seconds and store
> > the weather data over an extended period of time, such as a year.
>
> That's not going to be cheap. =A0You're talking about several tens of
> megabytes of data there!

I believe about 2GB of data. Hence my desire to use an USB memory
stick,
which was mentioned later in the post.
This can be used to log the data, which can then be transferred to a
PC and
the data on the USB memory device can be erased to allow re-use. A
2GB
memory stick costs about =8012 ($18) here, and the price is reducing.
>
> > The
> > weather data acquired should be stored with the date and time.
>
> That's at least 3 bytes for the time-stamp alone, and you would be
> storing 15 million samples per year. =A0That makes 45 MB before you've
> stored the first bit of actual payload data.
>
> > 1. Very small power consumption. It would be nice if the uC would be
> > capable of operating from the merest suggestion of a hint of a
> > picowatt :)
> > 2. A 1-Wire interface would be nice. This would make the development
> > process easier.
>
> I'm afraid that combination is flat-out impossible. =A0The 1-wire protocol=

> itself burns a lot more than a pico-watt on average, what with the line
> drivers fighting against the pull-up resistor every bit of the way.

I was attempting to use humour to emphasise that low power consumtion
is important. I guess I should stick to the day job :).
>
> > 3. The ability to store perhaps 2GB of data. I believe this would
> > require the means to either write/read a MMC/SD card or a USB memory
> > device (a memory stick, I believe these are called).
>
> A micro with a USB host implementation would be way beyond your power
> budget. =A0Writing flash is in itself quite an energy-consuming operation.=


Is there an alternative means to store 2GB of data?
>
> > 6. The ability to transfer the stored data to a PC. If a USB memory
> > device (stick) is used then this is already addressed, assuming that
> > FAT is used. If MMC/SD then an appropriate reader could be used =A0- but=

> > this would push up the overall cost. An alternative might be to have
> > some form of high speed data transfer mechanism, e.g. 10/100/1000
> > ethernet or possibly a USB port for communication with the PC.
>
> No, those wouldn't be alternatives, cost-wise, to a simple memory card
> reader for the PC to be equipped with. =A0Those are on the order of 10$ a
> pop, retail.

OK. So an Ethernet or USB comms capability to allow data transfer is
out.
But this has an impact on how I connect to the device (the data
logger) for
configuration purposes. The PC I am using to write this does not have
a
9-pin, or 15-pin, serial port. Are there other, common, means to
communicate
with the device? Or should I consider the use of USB/Ethernet for this
purpose?

Thanks for the reply.

Mike

On May 4, 6:21=A0am, Neil <NeilKu...@worldnet.att.net> wrote:
> linnix wrote:
> > On May 3, 11:41 am, Hans-Bernhard Br=F6ker <HBBroe...@t-online.de>
> > wrote:
> >> AC Me wrote:
> >>> I would like to construct a data logger. This data logger may be
> >>> located in areas remote from power and human kind. It will read 1-Wire=

> >>> interfaced weather instruments at an interval of 2 seconds and store
> >>> the weather data over an extended period of time, such as a year.
> >> That's not going to be cheap. =A0You're talking about several tens of
> >> megabytes of data there!
>
> >>> The
> >>> weather data acquired should be stored with the date and time.
> >> That's at least 3 bytes for the time-stamp alone, and you would be
> >> storing 15 million samples per year. =A0That makes 45 MB before you've
> >> stored the first bit of actual payload data.
>
> > A 45MB compact flash is less than $1, if you can still find it so
> > small.
> > A couple of Gs are reasonable in price too.
>
> >> =A0Writing flash is in itself quite an energy-consuming operation.
>
> > But you can buffer the data and only write every few minutes.
>
> Sure it is possible. =A0But as a beginners project? =A0What is you power
> budget? How many what hours is the protect? =A0Many small MCUs can do the
> job PIC, AVR, MP430. =A0None can talk to a USB Stick without another chip.=

> =A0 This should kill you power budget. =A0None have a 1-wire interface. =
=A0I
> am not sure any thing does.
> What do you know, any software or hardware? =A0ASM, C, Basic?- Hide quoted=
 text -
>
> - Show quoted text -

Thanks for the response. I would like the power consumption to be as
low as possible.
The time taken to bring this to completion is not important to me. The
primary purpose is
so that I can learn. I have looked at lots and lots of uCs and just
became even more
bewildered than I am normally :). That's why I asked you guys - I
though I might get a list
of a few uCs that come close and from which I could choose the most
appropriate device.

For instance, the PIC18F97J60 has 10BT ethernet, but no USB, no 1-Wire
and no LCD
drive capability. The PIC18F85J90 has an LCD drive capability, but no
ethernet or USB.
The PIC 18F13K50 has USB 2.0, but no ethernet or LCD. The MSP430CG4616
has LCD
but no ethernet, no USB, etc. The Atmel AT32UC3A0512 has 10/100
ethernet and USB but
no LCd and is knda high power (in my view although Atmel claim low
power). The Maxim
MAXQ2000 has a RTC, LCD, 1-Wire but no USB or ethernet.

=46rom other posts to this forum, I note that a company called FTDI
manufacture a chip
(well chips) to add a USB port to a uC using SPI, if I recall
correctly.

So perhaps the MAXIM part might be the most suitable, if I add the
FTDI part?
That would still leave the matter of communicating with a PC for
configuration
purposes. Any ideas?

=46rom my original post, I did (a long time ago) use machine code,
assembler and BASIC.
I taught myself C in the early '90s, but havn't had much experience
using this since then.

Mike