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LM3S1636_13 Datasheet, PDF (504/655 Pages) Texas Instruments – Stellaris Microcontroller
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Inter-Integrated Circuit (I2C) Interface
14.1 Block Diagram
Figure 14-1. 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
14.2
Signal Description
Table 14-1 on page 504 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 Assignment" lists the possible GPIO pin placements
for the I2C signals. The AFSEL bit in the GPIO Alternate Function Select (GPIOAFSEL) register
(page 301) should be set to choose the I2C function. 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 280.
Table 14-1. I2C Signals (100LQFP)
Pin Name
I2C0SCL
I2C0SDA
I2C1SCL
I2C1SDA
Pin Number
70
71
34
35
Pin Type
I/O
I/O
I/O
I/O
Buffer Typea 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.
14.3
Functional Description
Each I2C module is comprised of both master and slave functions which are implemented as separate
peripherals. For proper operation, the SDA and SCL pins must be connected to bi-directional
open-drain pads. A typical I2C bus configuration is shown in Figure 14-2 on page 505.
See “Inter-Integrated Circuit (I2C) Interface” on page 620 for I2C timing diagrams.
504
July 24, 2012
Texas Instruments-Production Data