Serial Backpack Power LED and Firmware

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churten
 
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Serial Backpack Power LED and Firmware

Post by churten »

Is it possible to disable (or dim?) the bright red power LED via a command over the USB/serial without new firmware for the ATtiny onboard?

Related, is it possible to flash new firmware to the ATtiny over the USB/serial connection, or would doing that require connecting to what looks like pads for an ICSP header?

Is the firmware source available somewhere that I might try to hack this in myself?

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adafruit_support_rick
 
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Re: Serial Backpack Power LED and Firmware

Post by adafruit_support_rick »

There is no firmware control for the power LED. It is wired in series with a resistor directly between +5 and GND. The only way to disable it is with a pair of wire cutters. The schematic (and a link to the firmware) is available in the tutorial.
To reflash the firmware, you would need to populate the ICSP header pins and use a programmer like the USBtinyISP.

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churten
 
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Re: Serial Backpack Power LED and Firmware

Post by churten »

If my eyes are not missing what's going on, it looks like it should be possible for me to remove the surface mount series resistor and (carefully) wire a "normal" resistor from its LED-side pad to one of the available GPIO pins. Of course, since I already soldered the backpack to the LCD, that plus attaching an ICSP header might be more trouble than it's worth, and electrical tape may be the best route for me here.

At any rate, thanks for the info and the great products :)

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adafruit_support_rick
 
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Re: Serial Backpack Power LED and Firmware

Post by adafruit_support_rick »

Your eyes aren't missing anything. You could certainly mod the board to drive the LED from a GPIO pin instead of directly from 5V.
I considered suggesting that, but I decided to link the schematic instead. I figured that if you couldn't see it for yourself, then you wouldn't have the necessary cred to be hacking the board in the first place :wink: .

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churten
 
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Re: Serial Backpack Power LED and Firmware

Post by churten »

The "UTSL" mantra works for open electronics as well as open source :)

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Re: Serial Backpack Power LED and Firmware

Post by adafruit_support_rick »

Churten wrote:The "UTSL" mantra
You learn something new everyday. Had to look that one up - never heard it before. And you are absolutely correct.
In many ways, that's a concise description of my function here: People ask questions, I UTS for the answers.

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