- Discrete LEDs
- Dot/Bar LEDs
- Matrix LEDs
- 7-Seg LEDs
- Serial -- Software
- Serial -- Hardware
- RS-232 via the MAX3232
- I2C -- EEPROM
- I2C -- DS1307 Real Time Clock
- 1-Wire -- DS18B20, Powered, Single-Drop
- 1-Wire -- DS18B20, Powered, Multi-Drop
- 1-Wire -- DS18B20, Parasitic, Multi-Drop
- TI Link Protocol -- Calculator Demo
- Infrared Communication
- MIDI -- Output Demo
- MIDI -- Input Demo
- MIDI to Analog Synth
LED Bar Graph -- Charlie/Multiplexed
We've really got to get the port pin count down! One approach is to use the circuit of LED Dot Graph via Charlieplexing, then multiplex that using code similar to LED Bar Graph via Multiplexing (the previous project). This reduces things to a very manageable four pins. The circuit is the same as in the former:
And the PMP code is much the same as in the latter project just mentioned. Refer back to the two links just cited for details.
Click to get the source code.
Click to get the schematic PDF.
Next Project: LED Bar Graph -- with the MAX7219