<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:10pt">I have been meaning for a long time to write a blog post along the lines of "How to pick an AVR chip", since I spend a lot of time thinking about that.<br><br>If it's a one-off it's often worth your while to just oversize for your needs. It sounds like the Mega328 is the way to go in your case, I believe that all the tiny max out at 8k(except for the oddball Tiny1634, that doesn't come in DIP anyways. <br><br><div><span>I was going to suggest looking at the (often)slightly cheaper Mega168, since those are all basically the same AVR but with reduced memory sizes.(Maybe a slight peripheral difference). Anyways, on both Digikey and Mouser, the 328 is cheaper than the 168. I think it's probably supply and demand at work for that. I think one of the reasons the 328 is so popular is that it does have
a "sweet spot" in balancing a lot of the amenities within the tiny/mega line. It's a great "default" AVR chip to start a design with, until some other driving factors start elevating the weight given to a particular chip parameter.<br></span></div><div style="color: rgb(0, 0, 0); font-size: 13.3333px; font-family: HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif; background-color: transparent; font-style: normal;"><br><span></span></div><div style="color: rgb(0, 0, 0); font-size: 13.3333px; font-family: HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif; background-color: transparent; font-style: normal;"><span>--Jon<br></span></div><div><br></div> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 10pt;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt;"> <div dir="ltr"> <hr size="1">
<font face="Arial" size="2"> <b><span style="font-weight:bold;">From:</span></b> Charles McClelland <chip@mcclellands.org><br> <b><span style="font-weight: bold;">To:</span></b> The MacDougals <paulmacd@acm.org> <br><b><span style="font-weight: bold;">Cc:</span></b> TriEmbed Discussion <triembed@triembed.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Friday, March 21, 2014 9:36 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [TriEmbed] Giving this Surface Mount Thing a Try - Transistor Help Needed<br> </font> </div> <div class="y_msg_container"><br><div id="yiv2087133051"><div class="yiv2087133051yqt2486624420" id="yiv2087133051yqtfd49051"></div><div><div class="yiv2087133051yqt2486624420" id="yiv2087133051yqtfd39383">Paul, </div><div><br clear="none"></div><div>With the Sleep, I2C, SPI and SD libraries, my code is currently 18k. Guess that settles it unless I was willing to go to a SPI
accelerometer and reduce the code.</div><div><br clear="none"></div><div>I have attached it here: </div></div></div><br><div id="yiv2087133051"><div><div></div><div><br clear="none"></div><div>Thanks,</div><div><br clear="none"></div><div>Chip</div><div><br clear="none"><div><div class="yiv2087133051yqt2486624420" id="yiv2087133051yqtfd16761"><div>On Mar 21, 2014, at 9:19 PM, The MacDougals <<a rel="nofollow" shape="rect" ymailto="mailto:paulmacd@acm.org" target="_blank" href="mailto:paulmacd@acm.org">paulmacd@acm.org</a>> wrote:</div><br class="yiv2087133051Apple-interchange-newline" clear="none"><blockquote type="cite"><div style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;" lang="EN-US"><div class="yiv2087133051WordSection1" style=""><div style="margin:0in 0in
0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73, 125);">How big is your code? If it is 8K or larger, you will have to go through the pain of reducing it. If it is much larger, you may not ever succeed.</span></div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73, 125);">If you decide to try the Tiny, I can help with examples of using pin change interrupt.</span></div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73, 125);"> </span></div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73,
125);">---> Paul</span></div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73, 125);"> </span></div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73, 125);"> </span></div><div><div style="border-style:solid none none;border-top-color:rgb(181, 196, 223);border-top-width:1pt;padding:3pt 0in 0in;"><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><b><span style="font-size:10pt;font-family:Tahoma, sans-serif;">From:</span></b><span style="font-size:10pt;font-family:Tahoma, sans-serif;"><span class="yiv2087133051Apple-converted-space"> </span>Charles McClelland [<a rel="nofollow" shape="rect" ymailto="mailto:chip@mcclellands.org" target="_blank"
href="mailto:chip@mcclellands.org">mailto:chip@mcclellands.org</a>]<span class="yiv2087133051Apple-converted-space"> </span><br clear="none"><b>Sent:</b><span class="yiv2087133051Apple-converted-space"> </span>Friday, March 21, 2014 5:41 PM<br clear="none"><b>To:</b><span class="yiv2087133051Apple-converted-space"> </span>The MacDougals<br clear="none"><b>Cc:</b><span class="yiv2087133051Apple-converted-space"> </span>Glen Smith; TriEmbed Discussion<br clear="none"><b>Subject:</b><span class="yiv2087133051Apple-converted-space"> </span>Re: [TriEmbed] Giving this Surface Mount Thing a Try - Transistor Help Needed</span></div></div></div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">Paul, </div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman',
serif;"> </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">I was planning on using the ATMEGA328 as that is what is on the Arduino Pro Mini board. Now that you mention it, I guess I could use the ATTiny84. I did try to use the pin change interrupt on the ATTiny84 but was not able to get it to awake form sleep except with a LOW signal. I wonder if that may be a limitation of the Sleep library I am using. </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">Back to the chip choice. Please let me know if I am missing anything on this list of pros and cons:</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div
style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">ATTiny84</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span class="yiv2087133051apple-tab-span"> <span class="yiv2087133051Apple-converted-space"> </span></span>- Pros: Cost, size, number of external components required</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span class="yiv2087133051apple-tab-span"> <span class="yiv2087133051Apple-converted-space"> </span></span>- Cons: This board uses both SPI and I2C so would need to learn how to “bit bang”</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span
class="yiv2087133051apple-tab-span"> <span class="yiv2087133051Apple-converted-space"> </span></span>- Don’t know - power / battery life?</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">ATMEGA328</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span class="yiv2087133051apple-tab-span"> <span class="yiv2087133051Apple-converted-space"> </span></span>- Pros: More pins for inputs and indicators (thinking about adding some more controls)</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span
class="yiv2087133051apple-tab-span"> <span class="yiv2087133051Apple-converted-space"> </span></span>- Cons: Cost, size, needs an external crystal</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">The easy choice would be to stay with the ATMEGA328 as I have the sketch working and have developed and field tested the design over the past 6 months. But, am I missing something that could sway me toward the Tiny?</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">Thanks,</div></div><div><div style="margin:0in 0in
0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">Chip</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div><div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">On Mar 21, 2014, at 4:42 PM, The MacDougals <<a rel="nofollow" shape="rect" ymailto="mailto:paulmacd@acm.org" target="_blank" href="mailto:paulmacd@acm.org" style="color:purple;text-decoration:underline;">paulmacd@acm.org</a>> wrote:</div></div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><br clear="none"><br clear="none"></div><div><div><div style="margin:0in 0in
0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73, 125);">Since you are collapsing all of the breakout boards, what are your plans for the processor?</span></div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73, 125);">As I recall, the reason for having to invert the signal was due to a limitation on the external</span></div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73, 125);">interrupt pin of the processor. Newer Atmel chips have pin change interrupts on all pins</span></div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span
style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73, 125);">and can handle either edge. So, if you go with an ATTiny 84 or similar, you don’t need the transistor.</span></div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73, 125);"> </span></div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73, 125);">---> Paul</span></div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73, 125);"> </span></div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span
style="font-size:11pt;font-family:Calibri, sans-serif;color:rgb(31, 73, 125);"> </span></div></div><div><div style="border-style:solid none none;border-top-color:rgb(181, 196, 223);border-top-width:1pt;padding:3pt 0in 0in;"><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><b><span style="font-size:10pt;font-family:Tahoma, sans-serif;">From:</span></b><span class="yiv2087133051apple-converted-space"><span style="font-size:10pt;font-family:Tahoma, sans-serif;"> </span></span><span style="font-size:10pt;font-family:Tahoma, sans-serif;">TriEmbed [<a rel="nofollow" shape="rect" ymailto="mailto:triembed-bounces@triembed.org" target="_blank" href="mailto:triembed-bounces@triembed.org" style="color:purple;text-decoration:underline;">mailto:triembed-bounces@triembed.org</a>]<span class="yiv2087133051apple-converted-space"> </span><b>On Behalf Of<span
class="yiv2087133051apple-converted-space"> </span></b>Charles McClelland<br clear="none"><b>Sent:</b><span class="yiv2087133051apple-converted-space"> </span>Friday, March 21, 2014 3:47 PM<br clear="none"><b>To:</b><span class="yiv2087133051apple-converted-space"> </span>Glen Smith<br clear="none"><b>Cc:</b><span class="yiv2087133051apple-converted-space"> </span>TriEmbed Discussion<br clear="none"><b>Subject:</b><span class="yiv2087133051apple-converted-space"> </span>Re: [TriEmbed] Giving this Surface Mount Thing a Try - Transistor Help Needed</span></div></div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">Glen, </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div
style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">I am using EAGLE - it allows you to set the names so I guess I have to take responsibility - Resister Base (RB) - I am learning so if there is a better naming convention I should be using, I would be open to it.</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">Thanks,</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">Chip</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New
Roman', serif;"> </div></div><div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">On Mar 21, 2014, at 1:29 PM, Glen Smith <<a rel="nofollow" shape="rect" ymailto="mailto:mrglenasmith@gmail.com" target="_blank" href="mailto:mrglenasmith@gmail.com" style="color:purple;text-decoration:underline;"><span style="color:purple;">mrglenasmith@gmail.com</span></a>> wrote:</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><br clear="none"><br clear="none"><br clear="none"></div></div><div><div><div><div><div><div class="yiv2087133051MsoNormal" style="margin:0in 0in 12pt;font-size:12pt;font-family:'Times New Roman', serif;">Charles,</div></div><div class="yiv2087133051MsoNormal" style="margin:0in 0in 12pt;font-size:12pt;font-family:'Times New Roman', serif;">As Bill said, there are single gate IC's to do what you want, a quick glance indicates the
cheapest (in one'sie two'sie quantities) is $0.33. But there are 2222 transistors available in SOT-23 packages: Jameco has them here:<span class="yiv2087133051apple-converted-space"> </span><br clear="none"><a rel="nofollow" shape="rect" target="_blank" href="http://www.jameco.com/webapp/wcs/stores/servlet/StoreCatalogDrillDownView?langId=-1&storeId=10001&catalogId=10001&freeText=2222%20sot-23&search_type=jamecoall" style="color:purple;text-decoration:underline;"><span style="color:purple;">http://www.jameco.com/webapp/wcs/stores/servlet/StoreCatalogDrillDownView?langId=-1&storeId=10001&catalogId=10001&freeText=2222%20sot-23&search_type=jamecoall</span></a><span class="yiv2087133051apple-converted-space"> </span><br clear="none">qty 10 available at $0.09 each. Or, to keep the comparison, DigiKey has them here:<span class="yiv2087133051apple-converted-space"> </span><br clear="none"><a rel="nofollow"
shape="rect" target="_blank" href="http://www.digikey.com/product-search/en?pv7=2&FV=142c0042&k=MMBT2222A&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25" style="color:purple;text-decoration:underline;"><span style="color:purple;">http://www.digikey.com/product-search/en?pv7=2&FV=142c0042&k=MMBT2222A&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25</span></a><span class="yiv2087133051apple-converted-space"> </span><br clear="none">(for one'sie two'sie quantities) at $0.18 each.</div></div><div class="yiv2087133051MsoNormal" style="margin:0in 0in 12pt;font-size:12pt;font-family:'Times New Roman', serif;">It has been far too long since I did transistor circuit design to tell you whether what you have will do the inversion you want, but you can hook it up on a breadboard with your discrete's and see how it
works.</div></div><div class="yiv2087133051MsoNormal" style="margin:0in 0in 12pt;font-size:12pt;font-family:'Times New Roman', serif;">Since I'm sending this note anyway, is there a reason why you chose RA, RB RC designations? It took me a few minutes looking at your circuit to figure out that it was a designator rather than a ResistorCapacitor (RC) network. Maybe it is just what I'm used to working with. Which layout tool are you using? KiCAD or Eagle? If one of them forces me to use RA, RB, RC - I think I will use the other.</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">Glen</div></div></div><div><div class="yiv2087133051MsoNormal" style="margin:0in 0in 12pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div><div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">On Fri, Mar 21, 2014 at 12:46 PM, Bill Farrow <<a rel="nofollow"
shape="rect" ymailto="mailto:bill@arrowsreach.com" target="_blank" href="mailto:bill@arrowsreach.com" style="color:purple;text-decoration:underline;"><span style="color:purple;">bill@arrowsreach.com</span></a>> wrote:</div></div><div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">Charles,</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;">There are single logic gate ICs in surface mount which should do what you want. Here's my quick digikey search.</div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><a rel="nofollow" shape="rect" target="_blank"
href="http://www.digikey.com/product-search/en?pv247=24&pv64=1&pv667=1&pv69=3&FV=fff40027%2Cfff8019d&k=single+gate&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25" style="color:purple;text-decoration:underline;"><span style="color:purple;">http://www.digikey.com/product-search/en?pv247=24&pv64=1&pv667=1&pv69=3&FV=fff40027%2Cfff8019d&k=single+gate&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25</span></a></div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"> </div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="color:rgb(136, 136, 136);"> </span></div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span
style="color:rgb(136, 136, 136);">Bill</span></div></div><div><div style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:'Times New Roman', serif;"><span style="color:rgb(136, 136, 136);"> </span></div></div></div><div class="yiv2087133051MsoNormal" style="margin:0in 0in 12pt;font-size:12pt;font-family:'Times New Roman', serif;"><br clear="none">_______________________________________________<br clear="none">Triangle, NC Embedded Computing mailing list<br clear="none"><a rel="nofollow" shape="rect" ymailto="mailto:TriEmbed@triembed.org" target="_blank" href="mailto:TriEmbed@triembed.org" style="color:purple;text-decoration:underline;"><span style="color:purple;">TriEmbed@triembed.org</span></a><br clear="none"><a rel="nofollow" shape="rect" target="_blank" href="http://mail.triembed.org/mailman/listinfo/triembed_triembed.org" style="color:purple;text-decoration:underline;"><span
style="color:purple;">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org</span></a><br clear="none">TriEmbed web site:<span class="yiv2087133051apple-converted-space"> </span><a rel="nofollow" shape="rect" target="_blank" href="http://triembed.org/" style="color:purple;text-decoration:underline;"><span style="color:purple;">http://TriEmbed.org</span></a></div></div></div></div></div></div></div></div></div></div></blockquote></div></div><div class="yiv2087133051yqt2486624420" id="yiv2087133051yqtfd88289"><br clear="none"></div></div></div></div><br><div class="yqt2486624420" id="yqtfd11493">_______________________________________________<br clear="none">Triangle, NC Embedded Computing mailing list<br clear="none"><a shape="rect" ymailto="mailto:TriEmbed@triembed.org" href="mailto:TriEmbed@triembed.org">TriEmbed@triembed.org</a><br clear="none"><a shape="rect" href="http://mail.triembed.org/mailman/listinfo/triembed_triembed.org"
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