SAM4L Datasheet, PDF (701/1185 Pages) ATMEL Corporation – ATSAM ARM-based Flash MCU

ATSAM4L4/L2
27.5 Application Block Diagram
Figure 27-2. Application Block Diagram
TWI
Master
TWD
TWCK
VDD
Rp Rp
Atmel TWI
serial EEPROM
Slave 1
I²C RTC
Slave 2
Rp: pull-up value as given by the I2C Standard
I²C LCD
controller
Slave 3
I²C temp
sensor
Slave 4
27.6 I/O Lines Description
Table 27-4.
Pin Name
TWD
TWCK
I/O Lines Description
Pin Description
Two-wire Serial Data
Two-wire Serial Clock
Type
Input/Output
Input/Output
27.7 Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
27.7.1 I/O Lines
TWD and TWCK are bidirectional lines, connected to a positive supply voltage via a current
source or pull-up resistor (see Figure 27-4 on page 703). 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-col-
lector to perform the wired-AND function.
The TWD and TWCK pins may be multiplexed with I/O Controller lines. To enable the TWIM, the
user must perform the following steps:
• Program the I/O Controller to:
– Dedicate TWD, TWCK as peripheral lines.
– Define TWD, TWCK as open-drain.
27.7.2
Power Management
If the CPU enters a sleep mode that disables clocks used by the TWIM, the TWIM will stop func-
tioning and resume operation after the system wakes up from sleep mode.
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