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Topic: Want to make an Arduino Mini-kinda Clone? (Read 5865 times) previous topic - next topic

Deviant

I believe that is what the the other post had me do.

It doesn't appear to make any difference.  Whether I try a light resistor or heavy.   On reset the little LED blinks and the mosfet triggers the other LED.

((Replaced the solenoid with an LED so the wife wouldn't kill me and make the news))

Deviant

Aha....

Great success.... or epic failure...  

I had been using pin 13, so I can test the mosfet and other stuff.

There is something strange about the pin 13.  The resistor doesn't seem to matter.

But I moved the pin to 12 and update the code variable.   Without the resistor.  It does funky stuffs... i.e. blink on boot.  With resistor.

It works as advertised.  Now the question is, what's strange about pin13.

jluciani

It shouldn't. On reset the pins initialize as inputs. The pulldown resistor
forces the gate to zero volts. A 10K to 100K resistor should be fine.

You wouldn't happen to be using pin 0 or 1 would you? These pins default to
communications pins on startup.

(* jcl *)
www: http://www.wiblocks.com
twitter: http://twitter.com/wiblocks

jluciani

IIRC pin 13 is the status LED in some bootloaders.

(* jcl *)
www: http://www.wiblocks.com
twitter: http://twitter.com/wiblocks

Deviant

Now, the question is.

Is this something that I should take into account on my PCB?

i.e. One resistor for every pin that I use.  So that they are always happy and dont' do freaky stuffs?

The little pin13 hates me.  It's killed a few brain cells last hour or so....

jluciani

I wouldn't.

Would you put a pull-up on each pin or a pull-down or one of each?
Should you add filter caps to each pin? Transient protection with series
current-limiting resistors?

There are too many possibilities. You would end up with a very large board
with a lot of unpopulated space. These application issues should be addressed
on the main application board.

(* jcl *)
www: http://www.wiblocks.com
twitter: http://twitter.com/wiblocks

Deviant

There is only one board. That's why I wondered if I should do it on the board.  Instead of

I'll have a button that will control a couple solenoids and possibly make some decisions based on other sensors.

I just don't want the solenoids doing anything they shouldn't.  

Until I want them to.

kanchun

I am interested to modify the Arduino Mini to use Atmega328 and also make use of the two extra pins on the PCB.  Since I am new to Arduino, I would like to take suggestion from all of you and publish it in the open source after it is done.  Thanks in advance.

Kan.

Deviant

Was your reply a question or a statement?

What two extra pins are you trying to use?

You should be able to ninja from the eagle files on the main site.  Then modify those to what you need.

I'm assuming that if you use this for commerical purposes, you have to meet the licensing requirements...   Which I think amounts to giving credit on where the original came from.

kanchun

Thanks for your reply.  It is a question since I am getting suggestion.  The Mini board I had in mind will be the same form factor as the Mini and Pro-Mini.  I have everything figured out and I also want to use the two extra pins, pin 19, 22 and attached LED and push switch on these two pins on the pcb. I also thinking of removing the regulator so that to reduce cost.  The finished PCB will plug into a standard 24 pins DIP socket.  Can this be feasible?

Thanks,

Kan.

Deviant

I suspose anything is feasible.  I'm not sure that you will be able to fit two more switchs and an extra LED plus 2 pin outs in the same formfactor of the mini-pro.

It's fairly type as it is.

I haven't tried to put one into a dip24, since that isn't want I wanted.  I'm not using most of the pins.

The smallest I had my eagle files and was able to successfully route all the wires was .7x1.2" or so.  My current layout is .8x2", because I added the pinouts to be able to burn the bootloader and program via usb programmer.

This is my Rev, I want to make sure it is going to work.  Before I start subtracting parts to make it smaller.    The smallest that I think that I can make it.  While staying on a 2 layer board and keeping the connector I want.  Is about .7x1".

whosawhatsis

Pins 19 and 22 are ADC-only. They do not function as digital I/O pins, so you can't run leds with them, and you would have to use analogRead to use a switch with them.

As for your pin 13 weirdness, I can confirm that the bootloader treats pin 13 uniquely, defaulting it to output mode and blinking it on startup.

kanchun

Thanks for your answers and I almost make a big mistake.  I am surprise to see Atmel didn't get a port properly and make them ADC only.
I am going to modify the design and should make it final.  I will remove the regulator circuit and just pull out the pins of 19 and 22.   I am not going to add any more LED nor switch on it.  It will fairly comfortable under one buck.  
My board will be the same size as the Pro Mini and that is 0.7x1.3".
I'll put the ICSP socket outside so that I can also program the bootloader/program if needed.
The remaining question is whether I should use 6 pins or I can use 5 pins for the serial/power/DTR port?  Any idea about the CTS pin?  Should I leave it or I need to keep it?  If I use a 5 pins one, then I can make the board 0.7x1.2", I hope.

whosawhatsis

#73
Aug 17, 2009, 06:18 pm Last Edit: Aug 17, 2009, 06:20 pm by whosawhatsis Reason: 1
On the mini, the CTS pin is connected to ground. The only reason it's there is for compatibility with TTL-232r cables. Other UART devices like Sparkfun's FTDI Basic Breakout use the same pinout so that they can be used interchangeably. You can get rid of it if you want, but you'll be making it a lot more difficult to connect a serial cable for programming.

kanchun

Thanks for your quick reply.
Can you tell me what a TTL-232r cables?  I am planning to build a USB to serial FT232RL Mini USB adapter that fit this board.
Thanks,

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