ST7232A datasheet(132/157 Pages) STMICROELECTRONICS

Part #	ST7232A

Description	8-BIT MICROCONTROLLER WITH 8K FLASH/ROM, ADC, 4 TIMERS, SPI, SCI INTERFACE

PDF	157 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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132 / 157 page

ST7232A

132/157

CONTROL PIN CHARACTERISTICS (Cont’d)

Figure 74. RESET pin protection1)2)3)4)

1. The reset network protects the device against parasitic resets.

2. The output of the external reset circuit must have an open-drain output to drive the ST7 reset pad. Otherwise the device

can be damaged when the ST7 generates an internal reset (watchdog).

3. Whatever the reset source is (internal or external), the user must ensure that the level on the RESET pin can go below

the VIL max. level specified in Section 12.9.1 . Otherwise the reset will not be taken into account internally.

4. Because the reset circuit is designed to allow the internal RESET to be output in the RESET pin, the user must ensure

that the current sunk on the RESET pin (by an external pull-up for example) is less than the absolute maximum value

specified for IINJ(RESET) in Section 12.2.2 on page 114.

0.01

µF

0.01

µF

VDD

EXTERNAL

RESET

CIRCUIT

USER

VDD

4.7k

Ω

Required

Recommended for EMC

ST72XXX

PULSE

GENERATOR

Filter

RON

VDD

WATCHDOG

INTERNAL

RESET

ST7232A Datasheet(PDF) 132 Page - STMicroelectronics