Question about DS18B20 and also KingBright 2 digit 7-segment LED
I'm pretty new to this so if I'm posting in the wrong forum, I apologize. I have two questions I was hoping someone could help me with.
Firstly, I'm working on a little project for monitoring temperatures (various locations within a room). I've seen a few of these out there - but I'm wanting to make my own as an entry project into micro-electronics.![tongue.gif](http://forums.parallax.com/images/smilies/tongue.gif)
Question 1:
I've got a BS2px24 attached to my Board of Education and right now am simply trying to read a DS18B20 (temp chip).
I've simply copied and pasted the Parallax example program used for OWIN and OWOUT into my dev. environment. (obviously making sure the pins match how I have the Board of Education setup).
When I run the program all I seem to get is 255 for everything - or $FF is you prefer.
The example program says it's meant to work with the DS1820, but can anyone see a reason it wouldn't work with the DS18B20. From reading through both datasheets - it seems they have the same ROM functions.
Question 2:
I'll be using a 2-digit 7-segment LED display from KingBright (it's blue
)
I've been able to successfully configure a single digit 7-segment (control it from a PBASIC program, etc) but can someone point me to a document that explains how to wire a 2, or 3 digit display on the BOE?
My problem comes from trying to figure out where to get the additional pins on the BOE.
In a more general sense, what do you do when you need to control more than 16 pins? Surely peoples projects have to exceed the board's limit now and again? Again - I'm sure it's trivial - just a fundamental point I don't understand yet.
Thanks Much!
Firstly, I'm working on a little project for monitoring temperatures (various locations within a room). I've seen a few of these out there - but I'm wanting to make my own as an entry project into micro-electronics.
![tongue.gif](http://forums.parallax.com/images/smilies/tongue.gif)
Question 1:
I've got a BS2px24 attached to my Board of Education and right now am simply trying to read a DS18B20 (temp chip).
I've simply copied and pasted the Parallax example program used for OWIN and OWOUT into my dev. environment. (obviously making sure the pins match how I have the Board of Education setup).
When I run the program all I seem to get is 255 for everything - or $FF is you prefer.
The example program says it's meant to work with the DS1820, but can anyone see a reason it wouldn't work with the DS18B20. From reading through both datasheets - it seems they have the same ROM functions.
Question 2:
I'll be using a 2-digit 7-segment LED display from KingBright (it's blue
![smurf.gif](http://forums.parallax.com/images/smilies/smurf.gif)
I've been able to successfully configure a single digit 7-segment (control it from a PBASIC program, etc) but can someone point me to a document that explains how to wire a 2, or 3 digit display on the BOE?
My problem comes from trying to figure out where to get the additional pins on the BOE.
In a more general sense, what do you do when you need to control more than 16 pins? Surely peoples projects have to exceed the board's limit now and again? Again - I'm sure it's trivial - just a fundamental point I don't understand yet.
Thanks Much!
Comments
·· On the 1-Wire device, please attach (not paste) the code you are running for verification.· As for expanding digits or even I/O, there are many ways to do this.· For the digits you could use a 7-Segment driver chip such as the MAX7219 or the MC14489.· Each of these is controlled by 3 I/O pins and can control 8 displays or 5 displays, respectively.· When expanding I/O, this can be done using shift registers.· There are examples of all these things in our Stamp Works manual, which can be downloaded free as a PDF file from the bottom of the following page.· I hope this helps.· Take care.
http://www.parallax.com/detail.asp?product_id=27220
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Chris Savage
Parallax Tech Support
I've attached the code I'm currently using to try and communicate with the DS18B20 as Project_002.bpx
Additionally, here is the output I am getting