rickyjar
Member level 2
User "satanistik” made this driver to enliven a bus magnetic display. At present, many vehicles is imported but there is no documentation concerning original drivers any longer or the companies, which manufactured them, stopped existing a long time ago. The driver can support a matrix with a FP2800A controller, maximally five segments with 28 pixels in each. Matrices can be 8, 13 and 16 pixel high. Work in the double-line mode is possible for 16 pixels. The driver receives announcements on the main similar to RS422 and decodes the frame received.
Transmission speed is 9600bps, however it can be freely defined, also the syntax of the frame can be changed in the program. There are two programs initiated with the driver – front tablet for the tablet with five segments, where a line number and text are displayed in one or two verses and only number for a single segment with auto-justification.
The electronic part of the project is based on the microcontroller ATmega8 in SMD, additionally four CD4094 shift registers control sixteen half-bridges supplying verses. Power supply is a LM317 regulator decreasing voltage from 24 to 20 and DC-DC step down converter from 20 to 5V for uC. The boards were fastened to the casing in plastic rails affixed to the lower lid. On the panel there is a TEST button turning off and on all the points alternatingly. The controlling program was written in the BASCOM, however intervals to support serial transmission and timer to measure out duration of impulses controlling coils were used.
Link to original thread - Sterownik wyświetlacza magnetycznego do autobusu