Difference between revisions of "SeriAlpha"

From Hackstrich
(Officially cancelling this project as SFE came out with the same thing.)
 
(7 intermediate revisions by the same user not shown)
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== Project Status ==
 
== Project Status ==
Revision 1 serial number 1 assembled and test code running successfully.  Revision 2 designed, laid out, and sent to @laen for PCBing.
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Revision 1 serial number 1 assembled and test code running successfully.  Revision 2 designed, laid out, and sent to @laen for PCBing.  PCBs and parts for rev 2 received.  Project cancelled as SparkFun came out with basically the same thing.
  
 
== Design Overview/Ideas ==
 
== Design Overview/Ideas ==
* Based around the ATtiny2313 in a QFN20 package
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* Based around the <s>ATtiny2313</s> ATtiny48 in a QFN20 package
 
* Individual transistors for each segment, so it will support all segments on at once and nifty things like PWMing segments
 
* Individual transistors for each segment, so it will support all segments on at once and nifty things like PWMing segments
 
* Built in character generator, so you can just tell the board what letter/number to display.
 
* Built in character generator, so you can just tell the board what letter/number to display.
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== Programming Revision 1 Boards ==
 
== Programming Revision 1 Boards ==
 
Revision 1 boards were accidentally missing a programming header.
 
Revision 1 boards were accidentally missing a programming header.
* MOSI - 5th pin down on I/O headers
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* Add a green wire from the 3rd pin down on the left I/O connector to the last resistor in the first bank under the MCU
* MISO - Tap a wire off the last resistor in the first bank under the MCU
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* Add a green wire from the 4th pin down on the left I/O connector to the first resistor pad in the second bank under the MCU
* SCK - 6th pin down on I/O headers
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* This enables programming via the left connector (top to bottom):
* RESET - Tap a wire off the unstuffed first resistor pad in the second bank under the MCU
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** 1 - GND
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** 2 - GND
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** 3 - MISO
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** 4 - /RESET
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** 5 - MOSI
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** 6 - SCK
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** 7 - VCC
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** 8 - VCC
  
[[Category:Current Projects]]
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[[Category:Cancelled Projects]]

Latest revision as of 13:00, 19 July 2011

SeriAlpha is a small backpack for alphanumeric LEDs (16 segment, specifically). It will accept I2C/SPI communications, and control the LED display attached to it.

Project Status

Revision 1 serial number 1 assembled and test code running successfully. Revision 2 designed, laid out, and sent to @laen for PCBing. PCBs and parts for rev 2 received. Project cancelled as SparkFun came out with basically the same thing.

Design Overview/Ideas

  • Based around the ATtiny2313 ATtiny48 in a QFN20 package
  • Individual transistors for each segment, so it will support all segments on at once and nifty things like PWMing segments
  • Built in character generator, so you can just tell the board what letter/number to display.
  • Targeting the SparkFun-sold 16segment LED displays

Revision 1 Design Issues

  • Unable to disable RESET pin due to silicon errata, so one segment won't work. - Fixed by switching to ATmega48 in revision 2.
  • No bypass caps on PCB - Fixed in revision 2.
  • Board could be smaller if MCU moved to bottom of board - Fixed in revision 2.
  • Resistor networks and dual-transistors would make assembly much easier - Fixed in revision 2.

Programming Revision 1 Boards

Revision 1 boards were accidentally missing a programming header.

  • Add a green wire from the 3rd pin down on the left I/O connector to the last resistor in the first bank under the MCU
  • Add a green wire from the 4th pin down on the left I/O connector to the first resistor pad in the second bank under the MCU
  • This enables programming via the left connector (top to bottom):
    • 1 - GND
    • 2 - GND
    • 3 - MISO
    • 4 - /RESET
    • 5 - MOSI
    • 6 - SCK
    • 7 - VCC
    • 8 - VCC