AT91SAM7S32-AI ATMEL [ATMEL Corporation], AT91SAM7S32-AI Datasheet - Page 250

• Manufacturer Part Number: AT91SAM7S32-AI
• Description: AT91 ARM Thumb-based Microcontrollers
• Manufacturer: ATMEL [ATMEL Corporation]

Product Dependencies
I/O Lines
Description
Power
Management
Interrupt
250
AT91SAM7S32 Preliminary
Table 56. I/O Lines Description
Both TWD and TWCK are bidirectional lines, connected to a positive supply voltage via a cur-
rent source or pull-up resistor (see Figure 90 on page 249). 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 steps:
•
•
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.
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.
Pin Name
TWD
TWCK
Program the PIO controller to:
–
–
Enable the peripheral clock.
Dedicate TWD and TWCK as peripheral lines.
Define TWD and TWCK as open-drain.
Pin Description
Two-wire Serial Data
Two-wire Serial Clock
6071A–ATARM–28-Oct-04
Input/Output
Input/Output
Type