<About This Manual - 1>
About This Manual
Objective
The primary objective of this LSI manual is to describe the features of this product including an
overview, CPU basic functions, interrupt, port, timer, serial interface, and other peripheral hardware
functions.
Each section consists of brief functional information, block diagrams and the details of control registers
including operation methods and setting examples.
Structure of This Manual
Each section of this manual consists of a title, summary, main text, hint, precautions and warnings, and
references.
The layout and definition of each section are shown below.
This page serves as an example to the explanations above. It may be different on an actual page.
Precautions and
warnings
Please be sure to read
the precautions to preven
any loss of functionality o
damage to the chip.
Main text
Section title
Sub section title
Header
Chapter number and
Chapter title
footer
Hint
chapter 2
Basic CPU
II-48 Reset
2.8 Reset
2.8.1 Reset operation
the CPU contents are reset and registers are intialized when the NRST pin (P
27) is pulled to low.
Initiating a Reset
There are two methods to initiate areset.
(1) Drive the NRST pin low for at least four clock cycles.
NTST pin should be holded "low" for more than 4 clock cycles (200 ns a
t a 20 NHz)
Figure:2.8.1 MInimum Reset PUlse Width
(2) Setting the P2OUT7 flag of the P2OUT register to "0" outputs low level at P
27 (NRST) pin. And transfering to reset by program (software reset) can be
executed. If the internal LSI is reset and register is initiated, the P2OUT
7 flag becomes "1" and reset is released.
On this LSI, the starting mode is NORMAL mode that high oscillation i
s the base clock.
When the power voltage low circuit is connected to NTST pin, circuit t
hat gives pulse for enough low level time at sudeen unconnected. And r
set can be generated even if its pulse is low level as the oscillation
clock is under 4 clocks,take notice of noise.
NRST pin
4 clock cycles
(200 ns at a 20 MHz)
Important information
from the text.
Page # and
section title.
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