TIMERS and TIMER/COUNTERS KS57C2308/P2308/C2316/P2316
11-10
TC0 COMPONENT SUMMARY
Mode register (TMOD0) Activates the timer/counter and selects the internal clock frequency or the
external clock source at the TCL0 pin.
Reference register (TREF0) Stores the reference value for the desired number of clock pulses between
interrupt requests.
Counter register (TCNT0) Counts internal or external clock pulses based on the bit settings in TMOD0
and TREF0.
Clock selector circuit Together with the mode register (TMOD0), lets you select one of four internal
clock frequencies or an external clock.
8-bit comparator Determines when to generate an interrupt by comparing the current value of
the counter register (TCNT0) with the reference value previously programmed
into the reference register (TREF0).
Output latch (TOL0) Where a clock pulse is stored pending output to the serial I/O circuit or to the
TC0 output pin, TCLO0.
When the contents of the TCNT0 and TREF0 registers coincide, the
timer/counter interrupt request flag (IRQT0) is set to "1", the status of TOL0 is
inverted, and an interrupt is generated.
Output enable flag (TOE0) Must be set to logic one before the contents of the TOL0 latch can be output to
TCLO0.
Interrupt request flag (IRQT0) Cleared when TC0 operation starts and the TC0 interrupt service routine is
executed and set to 1 whenever the counter value and reference value
coincide.
Interrupt enable flag (IET0) Must be set to logic one before the interrupt requests generated by
timer/counter 0 can be processed.