PT6961 LED controller (77 LEDs max), Keyboard scan (30 keys max)
Princeton PT6961 LED controller supports 6 Digits @ 12 Segments or 7 Digits @ 11 Segments. Also supports a scanned keyboard of upto 30 keys. SPI bus interface.
Library for Princeton PT6961 LED driver. Supports 6 digits @ 12 segments or 7 digits @ 11 segments. Also supports keyboard scanning of upto 30 keys. SPI interface.
This LED driver is found in frontpanel controllers of consumer electronics such as DVD players. The added features such as the matrix keyboard scanning are useful in these applications. The typical application schematic is shown below.
The device has a single pin for Data input (commands, LED segments) and Data output (key status). This pin can be connected to mbed SPI MOSI and MISO using a series/pull-up resistor.
The example code was tested on a salvaged display from a DVD/HDD. The LED seems custommade and the mapping between the LEDs and the controller outputs was reverse engineered.
The PT6961 may be found on ebay. Some LED displays have the device embedded. See here:
Note that the PT6961 is very similar to VFD controllers by the same vendor. See here.