This post is about the restoration of good old Philips CD Player’s display. In the 80’s, Philips released some types of players which utilized the National Semiconductor’s low pin count LED display: the NSM… series type. In this device there is a 35 bit shift register, and a LED driver, so it was easy to interface to system controller with 2 or 3 wires.
Unfortunately this display device is hard to find nowadays, and after 20-30 years, broken easily. (first just some of the segments, later all of the segment go dark.)
My goal was to keep the original look and feel of my Philips CD371 CD Player’s display, so i decided to disassemble the NSM4202 device to wire each led segment individually, and drive with external circuity. I was thinking that it is easy to implement the original function with a small microcontroller, with time multiplexed LED driving, but the original device is not time multiplexed (not flickered), it has steady and static light. So i looked, and find an excellent device, which has the original functionality for about 5 euros. (ST and MICREL is same)
This device is: Micrel’s MM5450.
…to be continued…
– UPDATE 2011 december 30 – I uploaded a small pdf to show some information about wiring and correct pinouts. You can download here:
NSM4202 or NSM4002 display clone
http://www.youtube.com/watch?v=KivqSCVOFFs
http://www.youtube.com/watch?v=DX2OHoBwQPw