SAM9263_14 Datasheet, PDF (456/1024 Pages) ATMEL Corporation – AT91SAM ARM-based Embedded MPU

33.6 Product Dependencies
33.6.1 I/O Lines
Both TWD and TWCK are bidirectional lines, connected to a positive supply voltage via a current source or pull-up
resistor (see Figure 33-2 on page 455). When the bus is free, both lines are high. The output stages of devices
connected to the bus must have an open-drain or open-collector to perform the wired-AND function.
The TWD and TWCK pins may be multiplexed with PIO lines. To enable the TWI, the programmer must perform
the following step:
z Program the PIO controller to dedicate TWD and TWCK as peripheral lines.
The user must not program TWD and TWCK as open-drain. It is already done by the hardware.
33.6.2 Power Management
z Enable the peripheral clock.
The TWI interface may be clocked through the Power Management Controller (PMC), thus the programmer must first
configure the PMC to enable the TWI clock.
33.6.3 Interrupt
The TWI interface has an interrupt line connected to the Advanced Interrupt Controller (AIC). In order to handle
interrupts, the AIC must be programmed before configuring the TWI.
SAM9263 [DATASHEET]
6249L–ATARM–28-Jun-13
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