NEC PD78P214 Manuale Utente
176
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PD78214 Sub-Series
7.3.7 Compare Register and Capture Register Operations
(1) Compare operation
Eight-bit timer/counter 2 performs an operation to compare the values set in the compare registers with timer
count values.
count values.
When the values set in the compare registers (CR20, CR21) coincide with count values of 8-bit timer 2 (TM2),
the coincidence signal is sent to the output control circuit. At the same time, the interrupt requests (INTC20,
INTC21) are generated.
the coincidence signal is sent to the output control circuit. At the same time, the interrupt requests (INTC20,
INTC21) are generated.
After the value of the CR21 register coincides with a count value of TM2, the count value of TM2 can be cleared.
Thus, 8-bit timer/counter 2 can operate as an interval timer for repeatedly counting up to the value set in the
CR21 register.
Thus, 8-bit timer/counter 2 can operate as an interval timer for repeatedly counting up to the value set in the
CR21 register.
Fig. 7-80 Compare Operation
Remark CLR21 = 0, CLR22 = 0
CE2
←1
OVF2
TM2
count value
count value
Count starts
Value of CR21
Value of CR20
Value of CR20
Value of CR21
Coincidence
Coincidence
Coincidence
FFH
FFH
INTC20
interrupt request
0H
INTC21
interrupt request
TO2 pin output
ENTO2=1
ALV2=1
TO3 pin output
ENTO2=1
ALV3=0
Inactive level
Cleared by software
Inactive level
Coincidence
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