Chapter 4 Setting Methods; Setting The External Event Counter Function Of 16-Bit Timer/Event Counter 00 - NEC 78K0S/K 1+ Series Application Note

External event counter

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Application note (44 pages)

Application note (49 pages)

Table of Contents

This chapter describes the external event counter function of 16-bit timer/event counter 00.

For other initial settings, refer to the

Control Application

Note. For interrupt, refer to the

Generated by Switch Input Application

Program (Low-Voltage Detection) Reset Generation During Detection at Less than 2.7 V Application

For how to set registers, refer to the user's manual of each product (78K0S/KU1+, 78K0S/KY1+, 78K0S/KA1+,

78K0S/KB1+).

For assembler instructions, refer to the

4.1 Setting the External Event Counter Function of 16-bit Timer/Event Counter 00

When using 16-bit timer/event counter 00 as an external event counter, the valid edge of the external event input

(input from the TI000 pin) is counted and an interrupt signal (INTTM000) is generated upon a match between the

TM00 counter and CR000 register.

The INTTM000 signal is generated at the following timings.

• INTTM000 signal generation timing (only first time)

= The number of times the valid edge of the external event input is detected × (CR000 setting value + 2)

• INTTM000 signal generation timing (second and following times)

= The number of times the valid edge of the external event input is detected × (CR000 setting value + 1)

The valid edge is detected for the first time, when the TI000 pin input signal is sampled at the f

the valid edge level is detected for two consecutive times. Therefore, noise with a short pulse width can be eliminated.

The following six types of registers are set when using 16-bit timer/event counter 00 as an external event counter.

• Capture/compare control register 00 (CRC00)

• 16-bit timer capture/compare register 000 (CR000)

• Prescaler mode register 00 (PRM00)

• 16-bit timer mode control register 00 (TMC00)

• Port mode register x (PMx)

• Port mode control register x (PMCx)