NEC PD78212, User Manual

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µ
PD78214 Sub-Series
(1) 8-bit timer 1 (TM1)
TM1 is a timer for counting up with the count clock specified by the lower 4 bits of prescaler mode register
1 (PRM1).
The count operation of TM1 can be enabled or disabled by timer control register 1 (TMC1).
TM1 allows only read operation using an 8-bit manipulation instruction. When the RESET signal is applied,
TM1 is cleared to 00H, and count operation stops.
(2) Compare register (CR10)
The CR10 register is an 8-bit register for holding a value that determines the period of interval timer operation.
When the value of the CR10 register coincides with the value of TM1, an interrupt request (INTC10) is
generated. This coincide with signal functions also as a real-time output port trigger signal. Count value clear
operation can also be performed when the value of CR10 coincides with the value of TM1.
The compare register allows both read and write operations using an 8-bit manipulation instruction. When
the RESET signal is applied, the compare register becomes undefined.
(3) Capture/compare register (CR11)
The CR11 register is an 8-bit register that can be set by capture/compare control register 1 (CRC1) as a compare
register used to detect a coincidence with the count value of TM1 or as a capture register used to capture the
count value of TM1.
(a) When CR11 is set as a compare register
The CR11 register functions as an 8-bit register for holding a value that determines the period of interval
timer operation.
When the value of the CR11 register coincides with the value of TM1, an interrupt request (INTC11) is
generated.
In addition, this coincide with signal functions also as a real-time output port trigger signal. Count value
clear operation can also be performed when the value of CR11 coincides with the value of TM1.
(b) When CR11 is set as a compare register
The CR11 register functions as an 8-bit register that captures the value of TM1 on a valid edge (capture
trigger) appearing on the external interrupt request (INTP0) input pin.
The value of the CR11 register is held until the next capture trigger occurs. After capture operation, TM1
can be cleared.
The CR11 register allows both read and write operations using an 8-bit manipulation instruction. When
the RESET signal is applied, the CR11 register becomes undefined.
(4) Edge detector
The edge detector detects a valid edge of an external input signal.
When the edge detector detects, on the INTP0 input pin, a valid edge specified in external interrupt mode
register 0 (INTM0), INTP0 and a capture trigger are generated. (See
Fig. 11-1 for information about the INTM0
register.)
(5) Prescaler
The prescaler generates count clocks from the internal system clock. From these count clocks generated by
the prescaler, a count clock is selected with the selector for the timer to perform count operation.