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Texas Instruments MSP430x1xx manual 15.2.1 I2C Module Initialization

Models: MSP430x1xx

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I2C Module Operation

15.2.1 I2C Module Initialization

The I2C module is part of the USART peripheral. Individual bit definitions when using USART0 in I2C mode are different from that in SPI or UART mode. The default value for the U0CTL register is the UART mode. To select I2C operation the SYNC and I2C bits must be set. After module initialization, the I2C module is ready for transmit or receive operation. Setting I2CEN releases the I2C module for operation.

Configuring and re-configuring the I2C module must be done when I2CEN =

0 to avoid unpredictable behavior. Setting I2CEN = 0 has the following effects:

-I2C communication stops

-SDA and SCL are high impedance

-I2CTCTL, bits 3-0 are cleared and bits 7-4 are unchanged

-I2CDCTL and I2CDR register is cleared

-Transmit and receive shift registers are cleared

-U0CTL, I2CNDAT, I2CPSC, I2CSCLL, I2CSCLH registers are unchanged

-I2COA, I2CSA, I2CIE, I2CIFG, and I2CIV registers are unchanged

When re-configuring the USART from I2C mode to UART or SPI mode the I2C, SYNC, and I2CEN bits must first be cleared, then the SWRST must be set and the UART or SPI initialization procedure must be followed. Failure to follow this procedure could result in unpredictable operation.

Note: Configuring the USART Module for I2C Operation After Reset

The required I2C configuration process is:

1)

Select I2C mode with SWRST = 1 (BIS.B #I2C + SYNC,&U0CTL)

2)

Disable the I2C module (BIC.B

#I2CEN,&U0CTL)

3)

Configure the I2C module with I2CEN = 0

4)

Set I2CEN via software (BIS.B

#I2CEN,&U0CTL)

Failure to follow this process may result in unpredictable USART behavior.

Note: Re-Configuring the USART Module for UART or SPI Operation

When re-configuring the USART module for UART or SPI operation from I2C operation, the required process is:

1) Clear I2C, SYNC, and I2CEN (CLR.B &U0CTL)

2)Set SWRST (MOV.B #SWRST,&U0CTL)

3)Continue with UART or SPI initialization procedure.

Failure to follow this process may result in unpredictable USART behavior.

USART Peripheral Interface, I2C Mode

15-5

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Texas Instruments MSP430x1xx manual 15.2.1 I2C Module Initialization
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MSP430x1xx specifications

The Texas Instruments MSP430x1xx series is a family of ultra-low-power microcontrollers that are highly regarded in the embedded systems community for their versatility and performance. Designed for applications ranging from portable instrumentation to low-power industrial devices, the MSP430x1xx combines flexibility and efficiency with advanced features tailored for energy-sensitive applications.

One of the standout characteristics of the MSP430x1xx is its ultra-low-power operation. This series offers several low-power modes that can significantly extend battery life in portable devices. The microcontroller can be in active mode, low-power mode, or even in a deep sleep state, allowing developers to optimize power consumption based on the application's requirements. In fact, some configurations can operate at just a few microamps, making it ideal for battery-operated devices.

Another key feature is the 16-bit RISC architecture that provides powerful processing capabilities while maintaining a low power profile. The MSP430x1xx series supports a maximum clock speed of 16 MHz, allowing for efficient task execution while consuming minimal energy. This architecture ensures that programs run smoothly while the microcontroller remains energy efficient.

The MSP430x1xx is equipped with various integrated peripherals, including analog-to-digital converters (ADCs), timers, and communication interfaces like UART, SPI, and I2C. The inclusion of a powerful ADC enables the microcontroller to handle sensor readings with high accuracy, making it suitable for applications like environmental monitoring and medical devices. The integrated timers provide essential functionality for real-time applications, allowing for event-driven programming and precise timing control.

Memory options in the MSP430x1xx series are also robust, with configurations offering flash memory sizes from 1 KB to 64 KB. This flexibility allows developers to choose the optimal memory size for their specific applications, accommodating a wide range of requirements.

Additionally, the MSP430x1xx microcontrollers are designed with a wide operating voltage range, typically from 1.8V to 3.6V, making them compatible with various power sources and further enhancing their usability in diverse applications.

In summary, the Texas Instruments MSP430x1xx series of microcontrollers is an excellent choice for developers seeking low-power, high-performance solutions for embedded applications. With an efficient architecture, a rich set of peripherals, and flexible memory options, these microcontrollers are positioned to meet the growing demands of modern electronic designs, particularly in battery-powered and energy-sensitive applications.