LM3S9B81 Datasheet, PDF (678/1155 Pages) Texas Instruments – Stellaris® LM3S9B81 Microcontroller

Inter-Integrated Circuit (I²C) Interface
16.1 Block Diagram
Figure 16-1. I²C Block Diagram
Interrupt
I²C Control
I2CMSA
I2CMCS
I2CMDR
I2CMTPR
I2CMIMR
I2CMRIS
I2CMMIS
I2CMICR
I2CMCR
I2CSOAR
I2CSCSR
I2CSDR
I2CSIM
I2CSRIS
I2CSMIS
I2CSICR
I²C Master Core
I2CSCL
I2CSDA
I²C Slave Core
I2CSCL
I2CSDA
I²C I/O Select
I2CSCL
I2CSDA
16.2
Signal Description
Table 16-1 on page 678 and Table 16-2 on page 678 list the external signals of the I²C interface and
describe the function of each. The I²C interface signals are alternate functions for some GPIO signals
and default to be GPIO signals at reset., with the exception of the I2C0SCL and I2CSDA pins which
default to the I²C function. The column in the table below titled "Pin Mux/Pin Assignment" lists the
possible GPIO pin placements for the I²C signals. The AFSEL bit in the GPIO Alternate Function
Select (GPIOAFSEL) register (page 318) should be set to choose the I²C function. The number in
parentheses is the encoding that must be programmed into the PMCn field in the GPIO Port Control
(GPIOPCTL) register (page 336) to assign the I²C signal to the specified GPIO port pin. Note that
the I²C pins should be set to open drain using the GPIO Open Drain Select (GPIOODR) register.
For more information on configuring GPIOs, see “General-Purpose Input/Outputs
(GPIOs)” on page 294.
Table 16-1. Signals for I2C (100LQFP)
Pin Name
I2C0SCL
I2C0SDA
I2C1SCL
I2C1SDA
Pin Number Pin Mux / Pin
Assignment
72
PB2 (1)
65
PB3 (1)
14
PJ0 (11)
19
PG0 (3)
26
PA0 (8)
34
PA6 (1)
18
PG1 (3)
27
PA1 (8)
35
PA7 (1)
87
PJ1 (11)
Pin Type
I/O
I/O
I/O
I/O
Buffer Type^a Description
OD
I²C module 0 clock.
OD
I²C module 0 data.
OD
I²C module 1 clock.
OD
I²C module 1 data.
a. The TTL designation indicates the pin has TTL-compatible voltage levels.
Table 16-2. Signals for I2C (108BGA)
Pin Name
I2C0SCL
Pin Number Pin Mux / Pin
Assignment
A11
PB2 (1)
Pin Type
I/O
Buffer Type^a Description
OD
I²C module 0 clock.
678
June 29, 2010
Texas Instruments-Advance Information