this micro-controller firmware controls a vacuum fluorescent display (VFD).

the VFD has been salvaged from a Samsung SER6500 cash register.
it already included supertex HV518 VFD drivers.

the micro-controller used is a STM32F103C8T6.
the software uses the libopencm3 library.

the firmware starts by testing all segments of the VFD, plays an animation, and finally displays the text typed in over the USB CDC ACM or USART1 ports.

the data is shifted out from the micro-controller to the drivers using SPI.
a timer will periodically refresh all parts of the VFD.

more details are available at https://wiki.cuvoodoo.info/doku.php?id=vfd_driver.