15.2.4 I2C Module Operating Modes

I2C Module Operation

The I2C module operates in master transmitter, master receiver, slave transmitter, or slave receiver mode.

Master Mode

In master mode, transmit and receive operation is controlled with the I2CRM, I2CSTT, and I2CSTP bits as described in Table 15−1. The master transmitter and master receiver modes are shown in Figure 15−8 and Figure 15−9. SCL is held low when the intervention of the CPU is required after a byte has been received or transmitted.

Table 15−1.Master Operation

I2CRM	I2CSTP	I2CSTT	Condition Or Bus Activity
X	0	0	The I2C module is in master mode, but is idle. No
			START or STOP condition is generated.

0	0	1	Setting I2CSTT initiates activity. I2CNDAT is used to
			determine length of transmission. A STOP condition is
			not automatically generated after the I2CNDAT
			number of bytes have been transferred. Software must
			set I2CSTP to generate a STOP condition at the end
			of transmission. This is used for RESTART conditions.

0	1	1	I2CNDAT is used to determine length of transmission.
			Setting I2CSTT initiates activity. A STOP condition is
			automatically generated after I2CNDAT number of
			bytes have been transferred.

1	0	1	I2CNDAT is not used to determine length of
			transmission. Software must control the length of the
			transmission. Setting the I2CSTT bit initiates activity.
			Software must set the I2CSTP bit to initiate a STOP
			condition and stop activity. This mode is useful if > 255
			bytes are to be transferred.

0	1	0	Setting the I2CSTP bit generates a STOP condition on
			the bus after I2CNDAT number of bytes have been
			sent, or immediately if I2CNDAT number of bytes have
			already been sent.

1	1	0	Setting the I2CSTP bit generates a STOP condition on
			the bus after the current transmission completes, or
			immediately if no transmission is currently active.

1	1	1	Reserved, no bus activity.

15-8USART Peripheral Interface, I2C Mode

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.

Texas Instruments MSP430x1xx manual 15.2.4 I2C Module Operating Modes, 1.Master Operation

Models: MSP430x1xx