Atmel Evaluation Kit AT91SAM9X35-EK AT91SAM9X35-EK Data Sheet
Product codes
AT91SAM9X35-EK
717
SAM9X35 [DATASHEET]
11055E–ATARM–10-Mar-2014
38.6 Product Dependencies
38.6.1 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
resistor (see
). 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.
TWD and TWCK pins may be multiplexed with PIO lines. To enable the TWI, the programmer must perform the following
step:
step:
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.
38.6.2 Power Management
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.
configure the PMC to enable the TWI clock.
38.6.3 Interrupt
The TWI interface has an interrupt line connected to the Interrupt Controller. In order to handle interrupts, the Interrupt
Controller must be programmed before configuring the TWI.
Controller must be programmed before configuring the TWI.
Table 38-4. I/O Lines
Instance
Signal
I/O Line
Peripheral
TWI0
TWCK0
PA31
A
TWI0
TWD0
PA30
A
TWI1
TWCK1
PC1
C
TWI1
TWD1
PC0
C
TWI2
TWCK2
PB5
B
TWI2
TWD2
PB4
B
Table 38-5. Peripheral IDs
Instance
ID
TWI0
9
TWI1
10
TWI2
11