STM6321/6322/6821/6822/6823/6824/6825

8/21

Ensuring a Valid Reset Output Down to

plications that require valid reset levels down to

(push/pull only, see Figure 9.) and a pull-up resis-

tor to active-high outputs (push/pull only, see Fig-

ure 10.) will ensure that the reset line is valid while

the reset output can no longer sink or source cur-

rent. This scheme does not work with the open

drain outputs of the STM6321/6322/6822.

The resistor value used is not critical, but it must

be large enough not to load the reset output when

cations, 100k

Ω is adequate.

Interfacing to Microprocessors with Bi-

directional Reset Pins

Microprocessors with bi-directional reset pins can

contend with the STM6321/6322/6821/6822/6823/

6824/6825 reset output. For example, if the reset

output is driven high and the microprocessor

wants to pull it low, signal contention will result. To

prevent this from occurring, connect a 4.7k

Ω resis-

tor between the reset output and the microproces-

sor’s reset I/O as in Figure 11..

(Active-Low Push-pull Outputs)

(Active-High, Push-pull Outputs)

Note: This configuration does not work on open drain outputs of the

STM6321/6322/6822.

Figure 11. Interfacing to Microprocessors with

Bi-directional Reset I/O

AI09138

STM6XXX

RST

GND

R1

AI09139

STM6XXX

RST

GND

R1

AI09135

STM6XXX

RST

GND

4.7k

Microprocessor

RST

Buffered Reset to other

System Components

GND