Datasheet

13
SAM9261 [DATASHEET]
Atmel-6062O-ATARM-SAM9261-Datasheet_21-Jun-16
5. I/O Line Considerations
5.1 JTAG Port Pins
TMS, TDI and TCK are Schmitt trigger inputs and have no pull-up resistors.
TDO and RTCK are outputs, driven at up to VDDIOP, and have no pull-up resistor.
The JTAGSEL pin is used to select the JTAG boundary scan when asserted at a high level (tied to VDDBU). It
integrates a permanent pull-down resistor of about 15 kΩ to GNDBU, so that it can be left unconnected for normal
operations.
The NTRST pin is used to initialize the embedded ICE TAP Controller when asserted at a low level. It integrates a
permanent pull-up resistor of about 15 kΩ to VDDIOP, so that it can be left unconnected for normal operations.
5.2 Test Pin
The TST pin is used for manufacturing test purposes when asserted high. It integrates a permanent pull-down
resistor of about 15 kΩ to GNDBU, so that it can be left unconnected for normal operations. Driving this line at a
high level leads to unpredictable results.
5.3 Reset Pin
NRST is an open-drain output integrating a non-programmable pull-up resistor. It can be driven with voltage at up
to VDDIOP. As the product integrates power-on reset cells, the NRST pin can be left unconnected in case no reset
from the system needs to be applied to the product.
The NRST pin integrates a permanent pull-up resistor of 100 kΩ minimum to VDDIOP.
The NRST signal is inserted in the Boundary Scan.
5.4 PIO Controller A, B and C Lines
All the I/O lines PA0 to PA31, PB0 to PB31, and PC0 to PC31 integrate a programmable pull-up resistor of 100 kΩ.
Programming of this pull-up resistor is performed independently for each I/O line through the PIO Controllers.
After reset, all the I/O lines default as inputs with pull-up resistors enabled, except those which are multiplexed with
the External Bus Interface signals that require to be enabled as Peripherals at reset. This is explicitly indicated in
the column “Reset State” of the PIO Controller multiplexing tables.
5.5 Shutdown Logic Pins
The SHDN pin is an output only, driven by Shutdown Controller.
The pin WKUP is an input only. It can accept voltages only between 0V and VDDBU.