17.2 ADC12 Operation

ADC12 Operation

The ADC12 module is configured with user software. The setup and operation of the ADC12 is discussed in the following sections.

17.2.1 12-Bit ADC Core

The ADC core converts an analog input to its 12-bit digital representation and stores the result in conversion memory. The core uses two programmable/selectable voltage levels (VR+ and VR− ) to define the upper and lower limits of the conversion. The digital output (NADC) is full scale (0FFFh) when the input signal is equal to or higher than VR+, and zero when the input signal is equal to or lower than VR− . The input channel and the reference voltage levels (VR+ and VR− ) are defined in the conversion-control memory. The conversion formula for the ADC result NADC is:

NADC	+ 4095		Vin * VR*
		VR) * VR*

The ADC12 core is configured by two control registers, ADC12CTL0 and ADC12CTL1. The core is enabled with the ADC12ON bit. The ADC12 can be turned off when not in use to save power. With few exceptions the ADC12 control bits can only be modified when ENC = 0. ENC must be set to 1 before any conversion can take place.

Conversion Clock Selection

The ADC12CLK is used both as the conversion clock and to generate the sampling period when the pulse sampling mode is selected. The ADC12 source clock is selected using the ADC12SSELx bits and can be divided from 1-8 using the ADC12DIVx bits. Possible ADC12CLK sources are SMCLK, MCLK, ACLK, and an internal oscillator ADC12OSC.

The ADC12OSC, generated internally, is in the 5-MHz range, but varies with individual devices, supply voltage, and temperature. See the device-specific datasheet for the ADC12OSC specification.

The user must ensure that the clock chosen for ADC12CLK remains active until the end of a conversion. If the clock is removed during a conversion, the operation will not complete and any result will be invalid.

17-4 ADC12

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 17.2 ADC12 Operation, 17.2.1 12-Bit ADC Core

Models: MSP430x1xx