Show Posts
Pages: [1] 2 3 ... 21
1  Using Arduino / Microcontrollers / Re: Why 16 Mhz clock??? on: July 21, 2014, 03:00:47 pm
I cannot even understand what you are trying to say.

inside joke between me and an ambitious moderator.

ive had to set up avr including arduino for couple hundred students and quite a few club members and only 3 cases of trouble at 16mhz so admit the likelihood  is low. at 8mhz margins are slimmer therefor more serious and ive seen lots more cases. the problem is not always clock mismatch between the two devices but also things like slew induced by cable capacitance and noise. we can go on and on about how nice round numbers are but none of that matters if you cant download a program or talk to another piece of gear.

ps lets not even bring up the issues with 1megabaud.
2  Using Arduino / Microcontrollers / Re: Why 16 Mhz clock??? on: July 21, 2014, 09:36:38 am
I think the easy uS timing was a big part of the decision
16MHz works well enough for 115K besides not everyone wants to run that speed

another for no punctuation. lol.

maybe it will get past his time.
3  Using Arduino / Microcontrollers / Re: Why 16 Mhz clock??? on: July 19, 2014, 11:37:34 am
Of course if you used an 8MHz crystal, then yes, the only real difference is that one allows you to do twice as much in the same time.

there is another significant  difference. 16mhz gives marginal divisor for 115kbaud serial and 8mhz is a disaster. in fact a properly tuned internal oscillator can provide more reliable communications.  its unfortunate arduino developers (and many groupies apparently) have infatuation with round numbers. there are many choices close to 16mhz that would give much smaller error for the uart.
4  Using Arduino / Microcontrollers / Re: core13: An Arduino core for the Attiny13 *testers wanted* on: July 19, 2014, 11:22:13 am
recompiling with winavr using "naked" directive will save about 30%. rewriting in asm about half. all tools to these are included in arduino.
5  Using Arduino / Microcontrollers / Re: core13: An Arduino core for the Attiny13 *testers wanted* on: June 07, 2014, 03:31:20 am
Is there a way to have 8 mhz?

8mhz is very easy by simply adjusting the osccal register. i do this on all my t13 projects to compensate for the oddball clock. now the same code works for nearly all my avr projects.
6  Using Arduino / Microcontrollers / Re: Trouble with using the internal clock on: June 04, 2014, 06:53:01 pm
Doesn't matter about the 3.3V, the programmer has no idea, all that is important is the clock frequency and processor. Use the "Arduino pro or mini pro (3.3v,8mhz) with atmega328" entry and you should be fine.

those are for external crystal but op wants internal clock. the easiest solution is to duplicate, rename, and edit one of those for new fuse. h=d0 and l=e2 works for me.
7  Using Arduino / Microcontrollers / Re: Updating the mighty-1284p core on: June 03, 2014, 10:48:11 pm
3 words: emmm.. essss... dosss... lol

ill also say these issues were one of the reasons i switched over to cp2102. far fewer problems with drivers, os compatibility, and handshake signals. not to mention better availability and lower cost.
8  Using Arduino / Microcontrollers / Re: some info regarding nRF24L01+ on: June 02, 2014, 05:24:17 pm
o is correct. ce is not required for successful communication and can simply be pulled up. reading the links and quotes posted here more carefully will confirm this.  those who are not quite so familiar are probably confusing it with csn which is the actual chip select. in fact none of the most popular transceiver chip (cc2500, nrf21l01, 7105, rfm22bm, etc) need more than the same basic 4 spi pins.
9  Using Arduino / Microcontrollers / Re: the DEFINITIVE tiny core package - an impossible dream? on: May 17, 2014, 04:15:51 pm
...if you cheat a lot in height. I don't know where you got "12" from

no cheating needed. 12mm (1/2") is exactly what you get when you solder 2 sils to the sides of a dip. these measurements were made just now with metric caliper but rounded off to nearest mm. and it was obvious you were not trying to make a small pcb.

anyway to finish this discussion and get back to "tiny core"  (im very interested also) ill say its silly to think ANY 14 pin breakout board will be bigger than a 28 pin regardless of chip package.
10  Using Arduino / Microcontrollers / Re: the DEFINITIVE tiny core package - an impossible dream? on: May 17, 2014, 03:54:59 pm
Ummm... that may be smaller from the 'top' but it more than makes up for it in height.

not quite. that photo over 10yrs old and instead of taking new ones heres some measurements:

pro: 19x33x12=7524  SOCKETED " chip with lots of pins soldered to it": 18x34x10=6120

so quite a bit smaller than pro. but not a true comparison considering that there are twice as many USEFUL pins available and it IS serviceable so:

non-socketed "chip with lots of pins soldered to it": 12x34x10=4080

and regarding my original point about 14pin vs promini exactly half that=2040

so about 1/4 promini size. forced to use a pcb it will be slightly larger. still less than 1/3 promini. true there are duplicate pins but unlike promini they are USEFUL duplicates for not only interfacing but also powering sensors, optos, servos, motors, etc etc.

true not everyone needs that kind of i/o but unused can always be ignored and i estimate will work with 90-95% of the  applications out there. sorta like promini or uno but quite a bit more compact and efficient. and a lot lower cost.

11  Using Arduino / Microcontrollers / Re: the DEFINITIVE tiny core package - an impossible dream? on: May 17, 2014, 12:53:42 pm
Did you bother to look at the picture I posted?

yes, and imo a huge waste. your pins are too far away from the dip, the led is about 10x bigger than necessary, similar redundancy of signals as promini, and...

why go on... it could be about half that size (1/3 promini) and retain all functionality. ive done boards for t24-84 and  m8-328,  smd, and dip for both and never considered duplication of isp or serial pins. for my own use i prefer NO pcb at all which is not only smaller but 1/10th cost and virtually zero turnaround. regulator/cap/crystal/led and notice there are power and ground pins available for every i/o. even a few extra because you can never have too many for the peripherals. this could be done with a pcb for little size penalty but also little advantage in my case:

edit: ooops... i misread "package" in the title and realize this is really ot. sorry. but i would like to say that every application needs i/o pins but imo there is little point to resistor (or any components) on reset, duplicating isp and serial pins, and other unneeded stuff.
12  Using Arduino / Microcontrollers / Re: the DEFINITIVE tiny core package - an impossible dream? on: May 17, 2014, 11:14:30 am
A 14-pin DIP on a piece of perfboard will most likely end up bigger than a Pro Mini

its true that a 14pin dip CHIP is bigger than a 32pin qfp CHIP but to imagine a 14pin dip BOARD would be bigger than a promini is ridiculous. specially considering the pin duplication, unnecessary parts, and wasted space from the sparkfun moron designer of promini. bringing out 14 pins to headers would end up much smaller than promini even with the single cap, crystal, and led circuit required. it looks like somebody has never bothered to actually measure either device or even glanced at the mechanicals.

bringing out 14 pins will always take a fraction that of bringing out 28 regardless of chip package all else equal.
13  Using Arduino / Microcontrollers / Re: Updating the mighty-1284p core on: May 16, 2014, 11:20:08 am
I went looking in the Playground for a how-to, and did not find it.  A few statements are made about building a custom bootloader but a "standard process" is not represented - that I can find.

i also had trouble getting the stuff that comes with ide to work. all kinds of issues with paths and h files. last year somebody, i think it was either bill or bill, sent me a zip of the opti source and it just up an ran. the only think different iirc were a couple of new batch files and i think the rest were the same. if nobody else comes along ill see if i can find it.

part of my problem is i work on many different computers, some of which i dont have the option to install or configure. so its a great help for guys like bill, bill, coding badly, and the others to lend a hand.
14  Using Arduino / Microcontrollers / Re: Updating the mighty-1284p core on: May 16, 2014, 11:13:01 am
it is very easy to build custom bootloader images.

its like with the avrdude situation. those who eat, live, and breath compiler find it hard to understand the ones that dont. in this case i was mostly looking for a stable  website like arduino to host a simple hex file that others can be referred to. online sources like git, google, savana, etc can be insanely hard to navigate and decrypt for those unfamiliar.  some of the guys i deal with dont even know how to unzip. how much better to just click and save.

haha... i see you caught my "suppository" dig. not everybody gets me.
15  Using Arduino / Microcontrollers / Re: 1M baud Optiboot for mighty1284p on: May 16, 2014, 08:25:21 am
I'm kind of surprised that you guys are able to get 1-Mbaud comms at all.

unless im mistaken stk500 protocol required pretty solid handshaking (wait for sp?) so its not likely to stream continuous. i think that was one of the reasons  tests from the freaks fellow showed little benefit to high rates beyond 57k and none over 115k. law of diminishing returns..

but i am suprised 1m or even 115k works for so many people due to hardware issues like cable distortions, clock offsets, etc.. when it works for a particular setup it works, but then somebody else tries and... well...
Pages: [1] 2 3 ... 21