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3 external reset pin, External reset pin – FUJITSU F2MCTM-16LX User Manual

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CHAPTER 7 RESETS

7.3

External Reset Pin

The external reset pin (RST pin) is an input pin used exclusively for a reset. Inputting an
L level signal generates an internal reset. For the MB90360-series, resets are generated
in synchronization with the CPU operating clock. However, initialization of external pin
is asynchronous with the CPU operating clock.

Block Diagrams of the External Reset Pin

Block diagram of the external reset pin

Figure 7.3-1 Block Diagram of the External Reset Pin

Note:

Inputs to the RST pin are accepted during cycles in which memory is not affected to prevent memory

from being destroyed by a reset during a write operation.

A clock is required to initialize the internal circuit. In particular, an operation with an external clock

requires clock input together with reset input.

RST

Pch

Nch

Pin

Input buffer

CPU operating clock
(PLL multiplication circuit,
2-frequency division of HCLK)

HCLK: Oscillation clock

Synchronization
circuit

CPU
peripheral function

External pin