7-segment led backpack problems

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mazatty
 
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Joined: Sun Oct 06, 2013 3:00 pm

7-segment led backpack problems

Post by mazatty »

hello, i recently purchaced a red 7-segment led backpack kit. i've gotten it hooked up to one of my digisparks and am having problems with the output. it looks like the display is installed correctly to the board. i know my soldering isn't pretty, but it should still work. i get junk on the display no matter what i send it. i can send commands to blink the display and change the brightness, and they work. i did have to change the calls to 'write()' in the adafruit led backpack library to 'send()' to get things to compile. here is the code i was running when taking the pictures. the brightness changes, but the lit segments don't.

Code: Select all

#include <TinyWireM.h>
#include <USI_TWI_Master.h>

#include <Adafruit_LEDBackpack.h>
#include <Adafruit_GFX.h>

Adafruit_7segment matrix = Adafruit_7segment();

void setup() {
  matrix.begin(0x70);
}

void loop() {
   for (uint16_t counter = 0; counter < 9999; counter++) {

    matrix.setBrightness(counter%15);

    matrix.println(counter);
    matrix.writeDisplay();
    delay(50);
  }

}
thank you for your help.


matt

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adafruit_support_rick
 
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Re: 7-segment led backpack problems

Post by adafruit_support_rick »

I'm afraid I know nothing about the digispark.
Do you need the pullups on SDA and SCL?
Have you got an arduino or Trinket you can test the backpack with?

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mazatty
 
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Re: 7-segment led backpack problems

Post by mazatty »

i do have pullups, 4.7k, on both sda and scl. i don't have anything else to test with.

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adafruit_support_rick
 
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Re: 7-segment led backpack problems

Post by adafruit_support_rick »

But do you need the pullups? What happens if you eliminate them?

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mazatty
 
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Re: 7-segment led backpack problems

Post by mazatty »

from what i read i am suppose to have the pullups. it doesn't appear to make a difference if the pullups are there or not.

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adafruit_support_rick
 
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Re: 7-segment led backpack problems

Post by adafruit_support_rick »

Don't know what to tell you. can you find an arduino someplace to test with?

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mazatty
 
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Re: 7-segment led backpack problems

Post by mazatty »

i've got a new arduino uno on the way. it'll be here in a couple of days.

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jpelectron
 
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Re: 7-segment led backpack problems

Post by jpelectron »

The digispark is an arduino, just with less pins...

The LCD from Digispark has the same pinout as the thing you pictured, see: https://s3.amazonaws.com/digistump-reso ... 7e_lcd.pdf

Pins 1 + 3 on JP3 is the digispark 5-pin connector
Pins 1 + 2 on JP1 is the LCD's 4-pin connector
Pin 1 = SCL
Pin 2 = SDA

Note pin assignements on the Digispark may be different then the numbering scheme your used to on "big arduino" See: https://s3.amazonaws.com/digistump-reso ... ematic.pdf

Also, note this confusing page: http://digistump.com/wiki/digispark/tutorials/modelbi2c
...about some very early digsparks where the LED causes problems with I2C devices

Lastly, could this be a timing issue?
See: http://digistump.com/wiki/digispark/tricks
I have digispark's driving the RGB Led strips from adafruit ( http://www.adafruit.com/products/1461 ) no problem, although with an external 5v supply (not the USB's 5v !!) but I read somewhere these strips were dependent on the 16Mhz as well?

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adafruit_support_rick
 
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Re: 7-segment led backpack problems

Post by adafruit_support_rick »

JPElectron wrote:but I read somewhere these strips were dependent on the 16Mhz as well?
You can run the NeoPixel strips from an 8MHz Trinket.

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