Read system clock
Function AddressDescription
RDTIM FFDERead system clock

This routine is used to read the system clock. The clock's resolution is a 60th of a second. Three bytes are returned by the routine. The accumulator contains the most significant byte, the X index register contains the next most significant byte, and the Y index register contains the least significant byte.

readClockRead the system clock and store in zero page
STYFREKZPLeast significant byte
STAFREKZP+2Most significant byte

Note: FREKZP (0x00FB) in this example is a 4 byte block of zeropage memory unused by Basic or Kernal and is available for user code.