Centronics Interface For Slide Fader

14 Cef8NTRONICS INTERFACE FOR SLIDE FADER The slide fader published earlier this year was originally designed for use with MSX computers. To further boost the interest in this versatile and simple-to-build circuit, an interface was developed that allows the fader to be driven from a standard Centronics port, which is available on practically any type of home computer. The slide fader discussed in Ref. (") is a computer peripheral that makes it poss- ible to control up to four slide projectors independently. Slide carriage control (forward/reverse) and lamp intensity (in 64 steps) are programmable on the com- puter. To keep the operation of the cir- cuit as simple as possible, one 8-bit out- put port is, in principle, required for each projector. The interface circuit de- scribed here effectively extends the num- ber of ports from one to four. One Cen- tronics port can drive up to four inter- faces of the type described here, so that the computer can program up to 16 in- dividual s...