MM54C90

The MM54C90/MM74C90 decade counter and the MM54C93/MM74C93 binary counter and complementary MOS (CMOS) integrated circuits constructed with N- and P-channel enhancement mode transistors. The 4-bit decade counter can reset to zero or preset to nine by applying appropriate logic level on the R₀₁, R₀₂, R₉₁ and R₉₂ inputs.

Also, a separate flip-flop on the A-bit enables the user to operate it as a divide-by-2, 5 or 10 frequency counter. The 4-bit binary counter can be reset to zero by applying high logic level on inputs R01 and R02, and a separate flip-flop on the A-bit enables the user to operate it as a divide-by-2, -8, or -16 divider. Counting occurs on the negative going edge of the input pulse.