EM6812F2TP24B datasheet(37/81 Pages) EMMICRO

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EM6812

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10.1.3 IO Operation

Port A input terminal status can always be read directly. All registers influencing the IO modes are bit-wise selectable. The

integrated switchable pull resistors and the selectable output drive mode allow a maximum of different terminal modes.

Refer to Table 32. Port A IO mode for the details.

The default state after power up on all PA terminals is input mode with pull-down resistor.

Table 32. Port A IO modes

Modes

Notes

Input mode

High-Z

Needs external drive

(PA[i] must never be floating)

Input mode with pull-up

Weak Hi

Pull-up has priority over pull-down

Input mode with pull-down

Weak Lo

Default state after Power-up

Output mode, CMOS high drive

Pull resistors disabled

Output mode, CMOS low drive

Pull resistors disabled

Output mode, open drain, high-Z

High-Z

Pull-down disabled

Needs external drive

(PA[i] must never be floating)

Output mode, open drain with pull-up

Weak Hi

Pull-up active

Output mode, open drain drive low

Pull-up disabled

Note:

Every port A input always needs at least one driver. A floating input can generate hazards and may induce cross current in

the input amplifier.

Note:

Avoid high frequency operation and fast transitions on PA7 while the 32kHz Crystal Oscillator is running. PA7 induced

crosstalk on OscOut terminal (PCB, Package) can influence the good Crystal operation.

EM6812F2TP24B Datasheet(PDF) 37 Page - EM Microelectronic - MARIN SA