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31  Development / Other Software Development / Re: 1-Wire Slave on: July 18, 2011, 04:08:31 am
I am targetting overdrive mode speeds.
32  Development / Other Software Development / Re: 1-Wire Slave on: July 16, 2011, 04:41:30 am
I was not aware of Maxim I2C 1-Wire bridge.  This could work for some sensors (ones that do not need post processing such as temp compensation, linearization, etc).  Thanks for the tip.  Would not help for actuators of course.

On family code I do not have a plan yet and am open for suggestion.
33  Development / Other Software Development / Re: 1-Wire Slave on: July 14, 2011, 04:19:13 am
8. What do you plan to turn into a 1-Wire slave device?  (e.g. I want to make a servo controllable through 1-Wire)
9. Which libraries do you intend to use?
10. Do you plan to make use of any interrupts?
11. On your slave device, would crippling millis / micros cause problems?  Consider this question carefully.  There are potentially hidden implications (like delay not working).
12. In your 1-Wire master code, do you read and verify the CRC?  Do you discard responses with an invalid CRC?

8. I am trying to use a 1-Wire slave lib to communicate with actautors and sensors over a 3 wire bus (power, gnd, signal).
9. I do not have that fully developed, but an I2C master lib running on a 1 wire slave will be needed to talk to I2C sensors so I can get them on the 1-wire bus.  I think the actuators and sensors will in general make minimal use of libraries, but rather serve as a flexible way to add them to an arduino based master that would add higher level functionality.
10. I general yes, for timing on servo loops and sensor interfaces.
11. Not a problem, it is an expected concession.  I can handle delays direct.
12. Yes, I plan to.

Thanks for your consideration.
34  Development / Other Software Development / Re: 1-Wire Slave on: July 14, 2011, 04:12:11 am

Sorry, missed that.  Yes tuned RC if needed.
35  Development / Other Software Development / Re: 1-Wire Slave on: July 09, 2011, 07:56:40 am
7. How do you plan to generate serial numbers?
Ideally over the 1-wire bus, else program in.

I don't understand.  Please clarify.

Not fully formed as an idea, but I was thinking along the lines of a base S/N that would be recognized as unprogrammed.  The master could then query slave, recognize the base number as a new node on the network, and assign it a new S/N.  I imagine this functionality could be accomplished a number of other ways, so not a hard requirement in my mind.
36  Development / Other Software Development / Re: 1-Wire Slave on: July 08, 2011, 05:04:16 am
5. Are you willing to give up one PWM pin for a 1-Wire slave library?

6. Is there any reason to support multiple 1-Wire devices from a single processor?
Yes, networking of multiple addressable slaves on a bus.  If you mean multiple addresseable slaves on a single processor, I do not have a need at present.

7. How do you plan to generate serial numbers?
Ideally over the 1-wire bus, else program in.
37  Development / Other Software Development / Re: 1-Wire Slave on: July 08, 2011, 04:50:40 am
There have been a few brief discussions of a 1-Wire slave library.  I'd like to revisit the idea.  Some topics to get us started...

1. 1-Wire slave should be available for which processors / boards?
Awesome.  I found this googling "AVR one wire slave".  +1 on a 1-Wiire slave lib.
My list: Same as your core list (ATTiny45/85, ATTiny2313/4313).  My main issue is network comms with low pin count devices.  I'm using TWI/I2C but at present I have to give up /RESET pin to use as I/O, but need to recover its use.  1 wire would be perfect, half duplex master/slave is fine and it would drop me from 4 wire to 3 wire connection which would be great.  Board would be DIY as shown in your Arduino Tiny thread.
2. Is there any reason to support 1 MHz processor speed?
Not for my applications, using 8 MHz internal or 16 MHz external.

3. Is it possible for an AVR processor to run from "parasitic power"?
This would be cool, but not essential for my present app as I need sufficient local power to run other things anyway. May be cool for networked low power sensor apps.

4. Do you think you would have any use for a 1-Wire slave library?
Definitely.  I hope this moves forward, I think the need is there and it would compliment your work on Arduino Tiny core.
38  Using Arduino / Microcontrollers / Re: Serial on attiny2313 using arduino-tiny to USART->I2C gateway on: July 02, 2011, 04:37:51 am
I documented getting TinyWireS working on an ATTiny85 here (,51984.msg447020.html#msg447020) Posts 28 and 29.  May or may not help.  Have not tried it on ATTiny2313 yet.

Are you getting any signs that the '2313 is alive (like a status LED flash)?  How are you clocking '2313?  Vcc is the same value for both Arduino and Tiny?  A 4.7K pull up on each of the correct pins? Carefully check pinout on each end (SCL is pin 19 on 2313 DIP package, SDA on pin 17).  Make sure these match to Arduino pinouts for SCL/SDA.

If none of that helps, not sure what next.  It should work on '2313 if it worked on '85.
39  Using Arduino / Microcontrollers / Re: Is the Arduino in trouble on: June 28, 2011, 04:28:53 am
Well - that's basically happened with the ChipKIT (I think that's right?) - based on the PIC32 line, with a gcc-based compiler for it.

Some quick Google shows the PIC32-gcc compiler from Microchip has a code size limitation of 64K?  You have to pay $800+ to remove limitiations.  If I got that right Arduino is under no threat.  There will be the inevitable market push to 32 bit as a compatible option, the toolchain is the key.  Arduino figured that out at the start.

Whoever commits to the Arduino free tools mindset with compatibility will claim the emerging market (imho).  I hope it is Atmel, but will remain open to options from vendors that get it.
40  Using Arduino / Sensors / Re: sine wave generator on: June 23, 2011, 05:04:14 am
Hi. I just want to know if it is possible to output 25 kHz sine wave using arudino Duemilanove? I will use it to drive my ultrasonic sensor. Thanks! smiley-grin

Did you get an answer to your original question?

Google DDS (for direct digital synthesis), NCO (numeric controlled oscillator) and read up.  These are techniques that let a micro generate programmable sine waves.

Here is a link to a good one

The link shows a fancy filter on the output, but you can get away with a simple RC if your not too picky on bandwidth and distortion.  Try it and let us know how it works.
41  Using Arduino / Microcontrollers / Re: Arduino Tiny on: June 22, 2011, 12:58:00 pm
@MGeo, mcu and clock of your project?

ATtiny85, ATTiny45 at 8 MHz internal osc, ATTiny2313 at 16MHz xtal
42  Using Arduino / Microcontrollers / Re: Arduino Tiny on: June 22, 2011, 04:47:42 am
Have you tried NewSoftwareSerial?

No, I will now though.

For tiny slaves, what about using 1-Wire instead of I2C?  Do you have a need for high-speed communications?

Yes I am looking for high speed comm, half-duplex for sensor/actuator network.  I2C works but with low pin count packages it would be nice to get down to a single wire if it is possible.  Comm is all command / respond so half-duplex would seem ok.  On thinking about your suggestion, 1-Wire looks like it may be ideal but I can find little on 1-Wire slave, only 1-Wire master.  Seems Dallas/Maxim tries to prevent slaves as proprietary.  I don't think they can own the concept of a single bi-directional wire.  Maybe OpenOneWire, based on AVR274 (
43  Using Arduino / Microcontrollers / Re: Arduino Tiny on: June 20, 2011, 05:26:23 am
Have you had any problems with it?  Made any changes?  Thought of any enhancements you'd like added?

No problems once I added pull-ups smiley-red

On enhancements, I would love to add onReceive and onRequest to slave lib but am not up the curve on C++ arduino enough to get very far.  I would love to help though.

For core enhancement, it would be nice to have a TinyDebugSerial Rx to go with the Tx.

I think having a full function I2C slave on ATTiny platform would be killer for the Arduino Tiny platform...big Arduino running I2C master code, and little ATTinyXXs running I2C slave code on a network of sensors, actuators and what not.

What do you say?

Best Regards,
44  Using Arduino / Motors, Mechanics, and Power / Re: controlling speed of simple vibration motor on: June 19, 2011, 08:31:25 am
PWM will variable rpm, model aircraft electric motor speed controls do that all the time.  This will give you open loop speed control of a brush motor.

Here is a Microchip  smiley-eek app note that explains concepts:

If you wanted more precise speed control independent of input voltage there are back-emf sense schemes that measure back-emf during the 'coast' portions of the PWM cycle to close a velocity loop.  Likely more than you are looking for here.

If it matters, remember that the vibratory force is a square function of RPM, (e.g. if you reduce the RPM in half, you will cut the vibratory force generated to 1/4 of the full RPM value).
45  Using Arduino / Microcontrollers / Re: Arduino Tiny on: June 19, 2011, 04:11:55 am
With the library BroHogan published?

Yep, BHogan TinyWireS lib as documented above in Reply #28.

Best Regards,
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