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microcontroller selection

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ssylee

New Member
I'm selecting a microcontroller to process input data from other external circuits and store text data for 2 or 3 days at each storage run. I also need the microcontroller to be low power-consuming as I need a selected battery to supply enough power to the microcontroller to last at least 2 or 3 days. I'm basically confused about the specifications that I need to look for in a microcontroller. From my understanding, microcontrollers are selected based on CPU speed, ROM/other storage capacity, amount of I/O ports and A/D converters, power consumption, and price. Can anyone suggest any more specifications that I need to look for?
 

eng1

New Member
Vdd vs. Clock frequency: if you decide the voltage, the maximum clock frequency specification must be met. For example: uC=PIC12F629, Vdd=3 V, fmax=10 MHz.
 
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ericgibbs

Well-Known Member
Most Helpful Member
ssylee said:
I'm selecting a microcontroller to process input data from other external circuits and store text data for 2 or 3 days at each storage run.
What will be the size of the stored text files?

I also need the microcontroller to be low power-consuming as I need a selected battery to supply enough power to the microcontroller to last at least 2 or 3 days.
What limitations do you have on the battery voltage/capacity?

I'm basically confused about the specifications that I need to look for in a microcontroller. From my understanding, microcontrollers are selected based on CPU speed,
Are the input data rates high and do they require lots of data processing?

ROM/other storage capacity, amount of I/O ports and A/D converters,
Do you require RS232 or other type of communication with a remote PC?

power consumption, and price.
Power consumption and price will be controlled by the requirements, as above.

Can anyone suggest any more specifications that I need to look for?
Let us have more detail on the questions asked, I am sure we could recommend a range of PIC devices.

Regards
 

bloody-orc

New Member
Make a list of what you need the microcontroller to do and then start searching. Open atmel.com and look the AVR's (8 bit micros). you can most definitely find what you need from there.
 

ssylee

New Member
Quote:
Originally Posted by ssylee
I'm selecting a microcontroller to process input data from other external circuits and store text data for 2 or 3 days at each storage run.
What will be the size of the stored text files?
Stored text files would be around 64 to 128 kb.

I also need the microcontroller to be low power-consuming as I need a selected battery to supply enough power to the microcontroller to last at least 2 or 3 days.
What limitations do you have on the battery voltage/capacity?
Battery voltage and capacity either follow the off-the-shelf ones or follow custom-made rechargeable batteries

I'm basically confused about the specifications that I need to look for in a microcontroller. From my understanding, microcontrollers are selected based on CPU speed,
Are the input data rates high and do they require lots of data processing?
Lots of data processing isn't really required, but input data rate could be quite high.

ROM/other storage capacity, amount of I/O ports and A/D converters,
Do you require RS232 or other type of communication with a remote PC?
I either need to plug in RS232 or better yet, just plug it into usb.

power consumption, and price.
Power consumption and price will be controlled by the requirements, as above.

Can anyone suggest any more specifications that I need to look for?
 

ericgibbs

Well-Known Member
Most Helpful Member
hi ssylee,
I will have a look thru the PIC specs and get back to you.
It looks like it will be a 18Fxxxx device with USB, the storage capacity of 128Kb maybe a problem, you may require extra flash storage.

A good site to browse thru is www.microchip.com

If you want to include a previous post in your reply, use the 'Quote' reply option.

Regards
 

ericgibbs

Well-Known Member
Most Helpful Member
hi,
The PIC 18F2455 has USB.
For extra storage space the 24FC512 CMOS serial EEPROM.

Download the datasheets from www.microchip.com
 

dipmicro

Member
If this is a commercial application (i.e. development hours cost money), did you consider a PDA with extension I/O card? Of course the built-in battery would not last for 2-3 days of constant full-power but standby-wakeup cycle may work.
 

beachracer

New Member
I too am in need of direction:

I need to take the on/off output from an array of 8 photo-sensors per board/circuit and translate/transfer them into an SQL database on a remote standalone system.

* Power supply is not an issue.

* I can use PS2, Serial or Bluetooth for transport of data.

* Data reporting rate is as low as once every 1 or 2 seconds per sensor (this is very flexible).

Seems simple enough - I just don't want to trip up on a small detail.

Suggestions?

Thanks

br
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Like you say, sounds simple - serial seems the obvious choice, as it's the easiest of the three to use - something as simple as a 16F628 using it's internal 4MHz oscillator is all you need. Send the 8 bits as a single byte, it's really very easy.

My tutorial 7.6 doesn't pretty well what you need, although it sends the data as 8 ASCII characters, 0's and 1's - which may suit you?.
 

beachracer

New Member
Nigel Goodwin said:
Like you say, sounds simple - serial seems the obvious choice, as it's the easiest of the three to use - something as simple as a 16F628 using it's internal 4MHz oscillator is all you need. Send the 8 bits as a single byte, it's really very easy.

My tutorial 7.6 doesn't pretty well what you need, although it sends the data as 8 ASCII characters, 0's and 1's - which may suit you?.
Thanks and awsome. I recieve my IR circuits tomorrow. I will review the tutorial and likely surface with some amateurish questions. Actually to keep the S2N ratio down I will PM you with some specifics.

Sadly, my late business partner was the microcontroller expert - I get the theory just rarely did any programming (I did do a fair bit of burning though) so I'm good with the colours just not with the brus strokes.

Thanks for the direction and help.

br
 
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