Hardware
Fully re-designed and piano-shaped PCB
Main changes:
- it's a piano! and buttons are more ergonomically aligned
- display is a different, clip-in Nokia 5110 LCD
- added back light to LCD, connected to PWM output
- crystal footprint and frequency, using now 12MHz instead of 16MHz and staying in spec for 3.3V supply voltage
- power supply selector for UART to either feed 5V USB voltage or 3.3V regulator voltage to a UART module, or don't supply any voltage at all if a self-powered USB to serial module is used
- general pin assignment changes for better routing
Firmware
Adjustments to comply with new hardware. No additional functionality.
Main changes:
- comes now with dedicated USB VID/PID pair \o/
- adjusting pin assignments
F_CPUset to 12MHz in Makefile and defined UART baud rate generator constants for 9600, 19200, 38400 and 57600 respectively- adjusted LCD bias system value for new Nokia 5110 display
- updated UART command line output for new versions, dates and URLs
General Notes
Obviously, Revision B hardware won't be compatible with earlier firmware versions and firmware code before commit 731fa44 should be avoided.
Likewise, any firmware after commit b6b119f should never be run on Revision A hardware.