The fx-602p released around 1982 is thought by many as the finest calculator Casio ever made. An evolution of the fx-502p with more memory and an alpha-numeric display. it was the last of the Casio step programmables and alpha was added to compete with the hp41c. hereafter, Casio moved onto basic programmable pocket computers like the fx-700p, although for a time, this model was concurrent with the fx-702p which wasn't sure whether it was a pocket computer or a calculator.
the 10+2 display also accommodates 11 alpha characters consisting of upper and lower case letters together with many useful symbols. the display is clear for a dot matrix type. there is no external contrast control, but the display contrast could be adjusted with a potentiometer after opening the unit.
The unit is programmable with constant memory, totaling of 512 steps and 22 memories (M00-M19 plus MF and M1F). this number can be partitioned, trading in steps for more memories. between 22 and 80 memories are allowed corresponding to between 512 and 32 steps. the base memories cannot be converted into more steps than 512. When you altered the memory partition to gain more memory registers (at the cost of 8 program steps for each memory register), you always got an extra F Register for every 10 Memory registers. If you had M20-M29, you also got M2F as a bonus. Where this extra memory space came from, I don't know.
Programmability is the same as the fx-502p with a comprehensive set of instructions including 4 tests, isz & dsz (increment/decrement and jump if zero) for compact loops, labels, subroutines and indirect addressing. The original F Register (located at the EXP key) was used for number comparisons. There were 4 kinds of comparison: x=0, x?0, x=F and x?F. Although the F register played an important role, there was nothing special about the other F Registers.
Our FX-602P was kindly donated by John D'Arcy of Birmingham
Other Systems Related To PsION:
This exhibit has a reference ID of CH6311. Please quote this reference ID in any communication with the Centre for Computing History.