ST90135 datasheet(79/190 Pages) STMICROELECTRONICS

Part #	ST90135

Description	8/16-BIT MCU FAMILY WITH UP TO 64K ROM/OTP/EPROM AND UP TO 2K RAM

PDF	190 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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79 / 190 page

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ST90158 - RESET AND CLOCK CONTROL UNIT (RCCU)

6.6 RESET/STOP MANAGER

The Reset/Stop Manager resets the MCU when

one of the three following events occurs:

– A Hardware reset, initiated by a low level on the

RESET pin.

– A Software reset, initiated by a HALT instruction

(when enabled).

– A Watchdog end of count condition.

The event which caused the last Reset is flagged

in the CLK_FLAG register, by setting the SOF-

TRES or the WDGRES bits respectively; a hard-

ware initiated reset will leave both these bits reset.

The hardware reset overrides all other conditions

and forces the ST9 to the reset state. During Re-

set, the internal registers are set to their reset val-

ues, where these are defined, and the I/O pins are

set to the Bidirectional Weak Pull-up mode.

Reset is asynchronous: as soon as the RESET pin

is driven low, a Reset cycle is initiated.

Figure 41. Oscillator Start-up Sequence and Reset Timing

VDD MAX

VDD MIN

OSCIN

INTCLK

RESET

OSCOUT

12ms (5V), 24ms (3V)

VR02085A

ST90135 Datasheet(PDF) 79 Page - STMicroelectronics