163CHAPTER 7 CLOCK GENERATORThe fastest instruction of theμPD78054 and 78054Y Subseries is executed with two clocks of the CPU clock.Therefore, relationships between the CPU clock (f CPU ) and the minimum instruction execution time are as shown inTable 7-2.Table 7-2. Relationship between CPU Clock and Minimum Instruction Execution TimeCPU Clock (f CPU ) Minimum Instruction Execution Time: 2/f CPUf X 0.4μsf X /2 0.8μsf X /2 2 1.6μsf X /2 3 3.2μsf X /2 4 6.4μsf X /2 5 12.8μsf XT /2 122μsRemarks 1. f X = 5.0 MHz, f XT = 32.768 kHz2. f X : Main system clock oscillation frequency3. f XT : Subsystem clock oscillation frequency
