EZ80L92MCU Datasheet, PDF (55/241 Pages) Zilog, Inc. – eZ80Acclaim Flash Microcontrollers

eZ80L92 MCU
Product Specification
40
Table 6. GPIO Mode Selection
GPIO Px_ALT2 Px_ALT1 Px_DDR Px_DR
Mode Bits7:0 Bits7:0 Bits7:0 Bits7:0 Port Mode
Output
1
0
0
0
0 Output
0
0
0
0
1 Output
1
2
0
0
1
0 Input from pin
High impedance
0
0
1
1 Input from pin
High impedance
3
0
1
0
0 Open-Drain output
0
0
1
0
1 Open-Drain I/O
High impedance
4
0
1
1
0 Open source I/O
High impedance
0
1
1
1 Open source output
1
5
1
0
0
0 Reserved
High impedance
6
1
0
0
1 Interrupt—dual edge triggered High impedance
7
1
0
1
0 Port B, C, or D—alternate function controls port I/O.
1
0
1
1 Port B, C, or D—alternate function controls port I/O.
8
1
1
0
0 Interrupt—active Low
High impedance
1
1
0
1 Interrupt—active High
High impedance
9
1
1
1
0 Interrupt—falling edge triggered High impedance
1
1
1
1 Interrupt—rising edge triggered High impedance
GPIO Mode 1. The port pin is configured as a standard digital output pin. The value writ-
ten to the Port x Data register (Px_DR) is presented on the pin.
GPIO Mode 2. The port pin is configured as a standard digital input pin. The output is
tristated (high impedance). The value stored in the Port x Data register produces no effect.
As in all modes, a Read from the Port x Data register returns the pin’s value. GPIO Mode
2 is the default operating mode following a RESET.
GPIO Mode 3. The port pin is configured as open-drain I/O. The GPIO pins do not feature
an internal pull-up to the supply voltage. To employ the GPIO pin in OPEN-DRAIN
mode, an external pull-up resistor must connect the pin to the supply voltage. Writing a 0
to the Port x Data register outputs a Low at the pin. Writing a 1 to the Port x Data register
results in high-impedance output.
GPIO Mode 4. The port pin is configured as open-source I/O. The GPIO pins do not fea-
ture an internal pull-down to the supply ground. To employ the GPIO pin in OPEN-
SOURCE mode, an external pull-down resistor must connect the pin to the supply ground.
PS013012-1004
PRELIMINARY
General-Purpose Input/Output