Home Built Bench Power Supply using ATMEGA328P

My workshop has a couple of bench power supply’s, one is an old Farnell TOPS 3D 3-rail tracking job, and the other is a 3-rail CSI CSI3005XIII with Constant Current functions. The farnell is all analogue but has no constant current control (current limiting only). The CSI is good but out the box doesn’t allow you to preset the constant current setting and thats what I want.”