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• Test boards seem to have a problem

  Anool Mahidharia • 02/13/2018 at 07:52 • 0 comments

  I received a couple of assembled boards with sketchy soldering. I tried to fix those as best as I can. But, the boards cause the computer to reset/reboot when plugged in to the USB port, so something seems to be badly amiss. I'm guessing the ATtiny chips are borked. More updates after I dig in some more.

• Programming morseKey

  Kevin Osborn • 06/10/2017 at 15:22 • 0 comments

  Mitxela (Tim Alex Jacobs) did the firmware based on the VUSB Easylogger code, and points to that if you want to rebuild it. If you are happy with the base functionality, you can just burn the hex file.

  Note: if you want to program the attiny85 in place, do so before soldering on the buzzer, as it overlaps with connector. I have some long headers that I stick in my programmer's cable and wedge it in the holes for a temporary connection to keep from having a big sticky-up header..

  I copied the easylogger source and merged it with mitxela's morsekey main.c. I also edited the Makefile to change the processor type (easylogger used attiny45) and programmer (I use usbtinyisp).

  If you want to change the programmer, it's an easy edit in the Makefile.

  First burn the fuses:

  • make fuse

  which essentially does:

  • avrdude -c usbtiny -p attiny85 -U hfuse:w:0xdd:m -U lfuse:w:0xc1:m

  and then

  • make flash

  which is

  • avrdude -c usbtiny -p attiny85 -U flash:w:main.hex:i
    

• Assembly of first prototypes

  Kevin Osborn • 06/10/2017 at 15:13 • 0 comments

  Wyolum's high school intern assembled the first units without any instructions, an he did a pretty good job. There were two problems that caused them to not work.

  1. The silkscreen on the processor did show where pin 1 was but didn't match the notch notation that would show socket alignment. All the processors were installed backward.

  2. The datasheet for the USB connector has the pins numbered backward from any USB pinout I found online. As a result, 5V and GND (and the data lines) were reversed, blowing out the processor. Flippintgthe connector to the other side of the board works.

  One cosmetic flaw: The electrolytic capacitor should have been lain on it's side.

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