Atmel Evaluation Kit AT91SAM9M10-G45-EK AT91SAM9M10-G45-EK Hoja De Datos
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AT91SAM9M10-G45-EK
553
SAM9M10 [DATASHEET]
6355F–ATARM–12-Mar-13
32.5
Application Block Diagram
Figure 32-2.
Application Block Diagram
32.5.1
I/O Lines Description
32.6
Product Dependencies
32.6.1
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 fol-
lowing step:
lowing 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.
32.6.2
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.
first configure the PMC to enable the TWI clock.
Table 32-3.
I/O Lines Description
Pin Name
Pin Description
Type
TWD
Two-wire Serial Data
Input/Output
TWCK
Two-wire Serial Clock
Input/Output
Host with
TWI
Interface
TWD
TWCK
Atmel TWI
Serial EEPROM
I²C RTC
I²C LCD
Controller
Slave 1
Slave 2
Slave 3
VDD
I²C Temp.
Sensor
Slave 4
Rp: Pull up value as given by the I²C Standard
Rp
Rp
Table 32-4.
I/O Lines
Instance
Signal
I/O Line
Peripheral
TWI0
TWCK0
PA21
A
TWI0
TWD0
PA20
A
TWI1
TWCK1
PB11
A
TWI1
TWD1
PB10
A