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.
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.
- 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.
- 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