AT32UC3C1512C Automotive Atmel Corporation, AT32UC3C1512C Automotive Datasheet - Page 456

• Manufacturer Part Number: AT32UC3C1512C Automotive
• Manufacturer: Atmel Corporation

23.6.2
23.6.2.1
23.6.2.2
23.6.2.3
9166C–AVR-08/11
Advanced Operation
Peripheral I/O Pin Control
Pull-up Resistor, Pull-down Resistor Control
Output Pin Timings
When a GPIO pin is assigned to a peripheral function, i.e. the corresponding bit in GPER is zero,
output and output enable is controlled by the selected peripheral pin. In addition the peripheral
may control some or all of the other GPIO pin functions listed in
ports those features. All pin features not controlled by the selected peripheral is controlled by the
GPIO.
Refer to the Module Configuration section for details regarding implemented GPIO pin functions
and to the Peripheral chapter for details regarding I/O pin function control.
Table 23-1.
Pull-up and pull-down can be configured for each GPIO pin. Pull-up allows the pin and any con-
nected net to be pulled up to VDD if the net is not driven. Pull-down pulls the net to GND.
Pull-up and pull-down are useful for detecting if a pin is unconnected or if a mechanical button is
pressed, for various communication protocols and to keep unconnected pins from floating.
Pull-up can be enabled and disabled by writing a one and a zero respectively to the correspond-
ing bit in the Pull-up Enable Register (PUER). Pull-down can be enabled and disabled by writing
a one and a zero respectively to the corresponding bit in the Pull-down Enable Register (PDER).
Figure 23-3
The same timing applies when performing a ‘set’ or ‘clear’ access, i.e. writing to OVRS or
OVRC. The timing of PVR is also shown.
Figure 23-3. Output Pin Timings
Function name
Output
Output enable
Pull-up
Pull-down
Drive strength
Write OVR to 1
Write OVR to 0
OVR / I/O Line
CLK_GPIO
PVR
shows the timing of the GPIO pin when writing to the Output Value Register (OVR).
I/O Pin function Control
GPIO mode
OVR
ODER
PUER
PDER
ODCRn
PB Access
Peripheral mode
Peripheral
Peripheral
Peripheral if supported, else GPIO
Peripheral if supported, else GPIO
Peripheral if supported, else GPIO
PB Access
Table
23-1, if the peripheral sup-
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