Panasonic MN101C77C, F77G Subtitle Sub-subtitle, Main text Key information, Summary, References

About This Manual

„Organization

In this LSI manual, this LSI functions are presented in the following order : overview, basic CPU functions, interrupt functions, port functions, timer functions, serial functions, and other peripheral hardware functions.

Each section contains overview of function, block diagram, control register, operation, and setting example.

„Manual Configuration

Each section of this manual consists of a title, summary, main text, key information, precautions and warnings, and references.

The layout and definition of each section are shown below.

Subtitle

Sub-subtitle

The smallest block in this manual.

Main text

Key information

Important information from the text.

Chapter 2 Basic CPU

2-8 Reset

2-8-1 Reset operation

The CPU contents are reset and registers are initialized when the NRST pin (P.27) is pulled to low.

„Initiating a Reset

There are two methods to initiate a reset.

(1)Drive the NRST pin low for at least four clock cycles.

NRST pin should be holded "low" for more than 4 clock cycles (200 nS at a 20 MHz).

NRST pin

4 clock cycles (200 nS at a 20 MHz)

Figure 2-8-1 Minimum Reset Pulse Width

(2)Setting the P2OUT7 flag of the P2OUT register to "0" outputs low level at P27 (NRST) pin. And transfering to reset by program (software reset) can be executed. If the internal LSI is reset and register is initiated, the P2OUT7 flag becomes "1" and reset is released.

[ Chapter 4. 4-4-2 Registers ]

On this LSI, the starting mode is NORMAL mode that high oscillation is the base clock.

When the power voltage low circuit is connected to NRST pin, circuit that gives pulse for enough low level time at sudeen unconnected. And reset can be generated even if its pulse is low level as the oscillation clock is under 4 clocks, take notice of noise.

Summary

Introduction to the section.

References

References for the main text.

Precautions and warnings

Precautions are listed in case.

Be sure to read these of lost functionality or damage.

II - 44 Reset

About This Manual 1