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1  Forum 2005-2010 (read only) / Interfacing / Re: using the tx and rx lines on: June 23, 2010, 01:19:18 pm
Ok, I looked at your programs again and I am doing the same thing to get the same results.   >smiley-sad I tried extra reads, swapping logic on Chip Select and the only thing that caused more consistent results was slowing the clock rate down.  I don't have an oscilliscope (yet) but I wonder if the clock still runs when you aren't transmitting or have the SS_PIN selected.

One thing I did do was tried hooking both 3.3 and 5v up on their respective pins.  I tried the 3.3v first and it kept shutting down the Duemilnove (to much draw?).  It wasn't till after I tried the 5v that I noticed the note about not using both at the same time.  I hope I didn't blow some circuit on the SS5500.  I haven't yet put a continuity tester on my wiring to see if I accidently put a short in to the 3.3v while wiring up all the GND pins.

I'm going to try and switch to the Vout method just to get going on the project.  I may come back and revisit the UART and SPI methods later.  I guess my first attempt again with SPI should include a more powerfull 3.3v supply.

I really want to do SPI because my final project calls for this and an SPI display.  Theoretically you can use SPI bus like IC2 with a separate pin for each CS.  Each device is supposed to pass on the commands if CS isn't selected . . . like it is doing right now.  
2  Forum 2005-2010 (read only) / Interfacing / Re: using the tx and rx lines on: June 14, 2010, 08:24:00 am

If you haven't figured it out yet it looks like you are not sending the whole command string.  The most likely reason you are getting what you send is because the board has echo turned on.  You have to send at least 11 bytes (ie '$sure Temp\n') to get a temperature.
3  Forum 2005-2010 (read only) / Interfacing / Re: humidity sensor on: May 14, 2010, 11:06:26 pm
Yes that is a serial type interface, notice the bit shift in the one digital input pin not an analog pin.  A typical thermisister uses an analog input pin.  The schematic and scheme are a single use routine.  The SPI library is reusable code for other SPI devices too.  I haven't read a lot about the subject but I think the difference between SPI and I2C is that I2C allows multiple devices on the same pair of wires and each one is polled using an address.  That is sort of the way ethernet works.  Each packet has a mac address of it's destination.
4  Forum 2005-2010 (read only) / Interfacing / Re: humidity sensor on: May 13, 2010, 11:20:16 pm
The auction mentions SPI.  That is a form of Serial interfacing like I2C.  Other temperature and humidity sensors like from sparkfun and solarbotics use analog inputs like a pot.

There is an SPI library over in the Playground under Interfacing with Hardware. smiley
5  Forum 2005-2010 (read only) / News / Re: How to pronounce "Arduino" ? on: May 08, 2010, 10:26:39 am
I haven't seen any mention of questions 2-3.  I read somewhere, maybe here on or an EBay auction, that it was named after an italian king.

Waiting for my first demon love board to come.  Ok, that is how I pronounce it, I didn't study Italian but it supposedly means 2009.
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