I2C Module Operation

15.2.7 Using the I2C Module with Low Power Modes

The I2C module can be used with MSP430 low-power modes. When the internal clock source for the I2C module is present, the module operates normally regardless of the MSP430 operating mode. When the internal clock source for the I2C module is not present, automatic clock activation is provided. When the I2C module is in the idle state, I2CBUSY = 0, and the I2C clock source I2CIN is disconnected from the I2C module state machine, saving power.

When the I2C clock source is inactive, the I2C module automatically activates the selected clock source when needed, regardless of the control-bit settings for the clock source. The clock source remains active until the I2C module returns to idle condition. After the I2C module returns to the idle condition, control of the clock-source reverts to the settings of its control bits.

Automatic I2C clock activation occurs when:

-In master mode, clock activation occurs when I2CSTT = 1 and remains active until the transfer completes and the I2C module returns to the idle condition.

-In slave mode, clock activation occurs when a START condition is detected and remains active until the transfer completes and the I2C module returns to the idle condition. After detection of the START condition, the STTIFG flag is set, and the module holds the SCL line low until the clock source becomes active. Once the source is active, the I2C module releases the SCL line to the master.

When the I2C module activates an inactive clock source, the clock source becomes active for the whole device and any peripheral configured to use the clock source may be affected. For example, a timer using SMCLK will increment while the I2C module forces SMCLK active.

USART Peripheral Interface, I2C Mode

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Texas Instruments MSP430x1xx manual Using the I2C Module with Low Power Modes
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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.
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