ST6391 datasheet(31/68 Pages) STMICROELECTRONICS

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Figure 30. I/O Configuration Diagram

(Open Drain 12V)

Figure 31. I/O Configuration Diagram (Open Drain 5V, Push-pull)

Input/Output Configurations

The following schematics show the I/O lines hard-

ware configuration for the different options. Figure

30 shows the I/O configuration for an I/O pin with

open-drain 12V capability (standard drive and high

drive). Figure 31 shows the I/O configuration for an

I/O pin with push-pull and with open drain 5V capa-

bility.

Notes :

The WAIT instruction allows the ST639x to be

used in situations where low power consumption is

needed. This can only be achieved however if the

I/O pins either are programmed as inputs with well

defined logic levels or have no power consuming

resistive loads in output mode. As the same die is

used for the different ST639x versions the unavail-

able I/O lines of ST639x should be programmed in

output mode.

Single-bit operations on I/O registers are possible

but care is necessary because reading in input

mode is made from I/O pins while writing will di-

rectly affect the Port data register causing an unde-

sired changes of the input configuration.

INPUT/OUTPUT PORTS (Continued)

ST6391,92,93,95,97,99

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