Difference between revisions of "SeriAlpha"
From Hackstrich
(ATtiny48 is now the MCU.) |
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== Design Overview/Ideas == | == Design Overview/Ideas == | ||
| − | * Based around the ATtiny2313 in a QFN20 package | + | * 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. | ||
Revision as of 00:33, 4 October 2010
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.
Contents
Project Status
Revision 1 serial number 1 assembled and test code running successfully. Revision 2 designed, laid out, and sent to @laen for PCBing.
Design Overview/Ideas
- Based around the
ATtiny2313ATtiny48 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.
- MOSI - 5th pin down on I/O headers
- MISO - Tap a wire off the last resistor in the first bank under the MCU
- SCK - 6th pin down on I/O headers
- RESET - Tap a wire off the unstuffed first resistor pad in the second bank under the MCU
