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1  Using Arduino / LEDs and Multiplexing / Re: 595 Shift Registers on: April 07, 2014, 10:26:40 am
Well... I found out the solution:

Using a pullup resistor into the OE line and only when that uC port goes down, the outputs are enable.

Thank you so much.
2  Using Arduino / LEDs and Multiplexing / 595 Shift Registers on: April 07, 2014, 10:23:53 am
Hey guys!!!

I am experiencing an issue regarding shift registers and its "ability" to randomly (or last shift register state) activate loads.

This issue occurs when I reset the arduino.

If I use an I/O port into the Output Enable pin and at the startup function I'll put that OE pin at 5V can I control this randomness?

Thanks





3  Using Arduino / General Electronics / I2C pull-ups resistors. on: February 05, 2014, 09:25:59 am
Hey smiley

When using the arduino's i2c ports (4/5) is it need to use external pull-up resistors?

As far as I know if the wire library is being used the internal pull-ups are automatically enabled.

Thanks
 
4  General Category / General Discussion / Re: Which is the plural word for Arduino: Arduini or Arduinos? on: October 07, 2013, 03:19:28 am
Thank you guys for the explanation smiley
5  General Category / General Discussion / Which is the plural word for Arduino: Arduini or Arduinos? on: October 04, 2013, 10:01:00 am
Hey,

Can anyone help me about the plural word for Arduino: is it Arduini or Arduinos?

Regards,

Vasco
6  Using Arduino / Microcontrollers / Re: Standalone board with ATMEGA8A on: July 28, 2013, 06:06:18 pm
Quote
I am using an USBasp to do the programming.
Yes, but are you using the "upload" button/command, or the "upload using progammer" (SHIFT-upload button)?
The bootloader uses the "stk500 protocol" over a serial connection.  This is ALSO the protocol and communications channel used by some device programmers (in fact, it is originally a device programmer communications protocol.)  So it's entirely possible that if you are using a USBASP programmer, that it would PARTIALLY work using the "upload" command, when you should be using the "shift-upload" command.

Here's the avrdude command used for "upload" (via the bootloader.) 
avrdude  -q -q -patmega328p -carduino -P/dev/cu.usbmodemfd3141 -b115200 -D -Uflash:w:Blink.cpp.hex:i

And here's the avrdude command used for "upload using programmer" (with "programmer" set to AVRISP.)
avrdude  -q -q -patmega328p -cstk500v1 -P/dev/cu.usbmodemfd3141 -Uflash:w:/Blink.cpp.hex:i
(Note that -carduino is approximately the same as -cstk500v1)

Problem solved! Thank you so much for your help.

I was not aware about the shift+upload.

Also, I was able to program the uC the way I report above because I made a change on the boards.txt file in the "atmega8.upload.protocol" from "arduino" to "usbasp".

I found it strange... But hey! I am not an expert ^^!

Regards
7  Using Arduino / Microcontrollers / Re: Standalone board with ATMEGA8A on: July 28, 2013, 06:22:01 am
Quote
- 10uF capacitor from reset to ground
This is wrong.  The 10uF from reset to ground is a thing done to prevent auto-reset from happening when you use an Arduino as an AVR programmer (using ArduinoISP sketch.)  You shouldn't normally have it there.
(I can't see how that would cause your problems, though.)
I agree with you. This capacitor can't make no harm! Because the reset line is sent from the USBasp directly to the reset pin.

Are you using "upload using programmer" ?  If not, and If your programmer somehow succeeded in being compatible with the Arduino bootloader, it could be getting commands that are incompatible with its functioning.  Specifically, the bootloader erases one page at a time before writing, but a programmer HAS to do a full chip-erase before it starts (HW programmers CAN'T do page erases!)  So when using the bootloader, Arduino gives avrdude the -D flag telling it NOT to do the chip erase; your symptoms could be explained by the programmer trying to overwrite the existing sketch without erasing the old one...
I am using an USBasp to do the programming. I tried with and without bootloader. This symptoms are the same.
I also agree with you. I beliese that USBasp is not able to perform a chip erase before flashing the uC,

The strange thing is that if I use eXtreme Burner to flash there is no problem at all. Maybe there is a bug on arduino IDE!

Regards
8  Using Arduino / Microcontrollers / Re: Standalone board with ATMEGA8A on: July 27, 2013, 03:34:36 pm
New developments:

After erasing the ATMEGA8A on eXtreme Burner I can do the following:

1) Program it OK with arduino.
2) Make a change on the code and flash it again. It's OK.
3) Make a second change on the code and flash it again. It's OK.
4) Third change on the code and a mismatch byte occur!!!

I can also do this after an erase on eXtreme Burner.
1) Program it OK with arduino.
2) Make NO changes on the code and I can flash it infinite times (I tried 4 times in a row so I guess I can say infinite smiley
3) Make a change on the code and flash it again. It's OK
4) Make a second change on the code and flash it again. It's OK
5) Third change on the code and a mismatch byte occur!!!


Now what? smiley-grin
9  Using Arduino / Installation & Troubleshooting / Re: New AUDRINO R3 trouble shooting on: July 27, 2013, 02:57:48 pm
Make sure you're using the right COM Port and your drivers are correctly installed.



10  Using Arduino / Microcontrollers / Re: Standalone board with ATMEGA8A on: July 27, 2013, 02:49:23 pm
Ops... I didn't read this:

----
avrdude: verifying ...
avrdude: verification error, first mismatch at byte 0x0110
         0x63 != 0x61
avrdude: verification error; content mismatch

avrdude done.  Thank you.
----

However, I don't understand why the content is mismatch!

Thanks
11  Using Arduino / Microcontrollers / Standalone board with ATMEGA8A [solved] on: July 27, 2013, 02:19:18 pm
Hey! How've you been?

I know that for some guys ATMEGA8 is so old school but I have a dozen of then and I don't want to toss then out smiley

I made a standalone board using:
- ATMEGA8A
- 16MHz resonator
- ICSP connections so I can use the USBasp
- 10K resistor from Vcc to reset
- 10uF capacitor from reset to ground
- Pushbutton in parallel with the above capacitor
- And a 7805 voltage regulator and the regular in and out capacitors.

The question is:
Whenever I try to re-upload a sketch the uC stays with the old firmware. Arduino IDE says that the upload was successful but it isn't. Why?

If I erase the ATMEGA and try to re-upload everything runs smoothly.

Any help?

Thanks

Regards.




12  Using Arduino / Installation & Troubleshooting / Re: New AUDRINO R3 trouble shooting on: July 27, 2013, 02:08:41 pm
Board == Arduino Uno

Programmer == Arduino as ISP

Also, make sure you're using the right COM port.

And you're done.

Good luck
13  Using Arduino / Displays / Re: LCD 4884 - Soldering the clamps on: June 05, 2013, 04:10:10 am
Sorry for my late feedback.

You're both right:

1) I also believe that the clamps are not meant to be soldered (they are stainless steel)
2) Maybe, bending the inner clamps and then soldering it into the PCB might be a solution
3) I already damaged the LCD (too much heat) but I am using another LCD module which the clamps are firmly attached into the PCB and the electrical contact is excellent.
4) I ordered another LCD (just the LCD) so I can replace the damaged one and still use the whole LCD board

Thank you so much for your help smiley

Regards.
14  Using Arduino / Displays / Re: LCD 4884 - Soldering the clamps on: May 31, 2013, 04:00:55 pm
You likely need to use some flux, when it heats up from the soldering iron it will clean the surfaces and the solder should stick.
Make sure you have a decently sized tip to heat everything up enough for the solder to flow pr0perly.

Thanks for the tip... but I can't get it working. The solder simply wont glue.

I have a quite nice flux but it's useless smiley-sad Maybe the metal shield is not compatible with solder :/

I'll try sanding the metal.
15  Using Arduino / Displays / LCD 4884 - Soldering the clamps on: May 31, 2013, 02:40:53 pm
Hey mates, how have you been?

I recently bought a 4884 LCD.

When I first inspect that piece of hardware I found out that the LCD was not soldered into the PCB. At first I was like:

"Nice, I can inspect the PCB which the LCD is covering". Well, it's exactly like any PCB around! lol.

Later I realized that to make sure the LCD won't flick, I must stick it into the PCB.

That's when the nightmare came. I was trying to solder those 4 holding clamps into the PCB but it's impossible because the solder won't glue into the LCD metal shield.

By the way, this is the back of the LCD module:
http://www.sainsmart.com/zen/albums/SKU/20/20-011/20-011-822/trade_spotting/05.JPG

My question is: Now what? smiley No one had this problem?!

I accept suggestions smiley

Thanks

Regards.

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