External Event Count Mode (Tpnmd2 To Tpnmd0 = 001B) - NEC V850E/PH2 User Manual

9.5.3 External event count mode (TPnMD2 to TPnMD0 = 001B)

In the external event count mode, external event count input (TEVTPn pin input) is used as a count-up
signal. When the external event count mode is set, count-up is performed using external event count
input (TEVTPn pin input), regardless of the setting of the TPnEEE bit of the TPnCTL0 register.
In the external event count mode, a match interrupt request (INTTPnCC0) is output upon a match
between the setting value of the TPnCCR0 register and the value of the 16-bit counter, and the 16-bit
counter is cleared.
When a value is set to the TPnCCR0 register with a write instruction from the CPU, it is transferred to
the CCR0 buffer register through anytime write, and is used as the value for comparison with the 16-bit
counter value.
In the external event count mode, the 16-bit counter is cleared only upon a match between the value of
the 16-bit counter and the value of the CCR0 buffer register.
16-bit counter clearing using the TPnCCR1 register is not performed. However, the setting value of the
TPnCCR1 register is transferred to the CCR1 buffer register and compared with the value of the 16-bit
counter, and an interrupt request (INTTPnCC1) is output if these values match.
Moreover, TOPn1 pin output is also possible by setting the TPnOE1 bit to 1.
The TPnCCR0 register can be rewritten when TPnCE = 1. When the TPnCCR1 register is not used, it is
recommended to set TPnCCR1 to FFFFH.
Cautions: 1. In external event count mode, when the content of the TRnCCR0 register is set to
m, the number of TEVTPn pin input edge detection times is m+1.
2. In external event count mode, do not set TPnCCR0 register to 0000H.
3. When the TPnCCR1 register value is set to 0000H in external event count mode
the corresponding interrupt (INTTPnCC1) does not occur immediately after start,
but after the first overflow of the timer (FFFFH to 0000H).
4. TOPn0 pin output cannot be used in external event count mode. Alternatively use
the interval timer mode (refer to section 9.5.2
in conjunction with TOPn0 pin output.
Remark: n = 0 to 7
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Chapter 9 16-Bit Timer/Event Counter P
User's Manual U16580EE3V1UD00
on page 279) and set TPnEEE = 1