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Texas Instruments MSP430x1xx Voltage Reference Generator, Internal Reference Low-Power Features

Models: MSP430x1xx

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ADC10 Operation

18.2.3 Voltage Reference Generator

The ADC10 module contains a built-in voltage reference with two selectable voltage levels. Setting REFON = 1 enables the internal reference. When REF2_5V = 1, the internal reference is 2.5 V. When REF2_5V = 0, the reference is 1.5 V. The internal reference voltage may be used internally and, when REFOUT = 0, externally on pin VREF+.

External references may be supplied for VR+ and VR− through pins A4 and A3 respectively. When external references are used, or when VCC is used as the reference, the internal reference may be turned off to save power.

External storage capacitance is not required for the ADC10 reference source as on the ADC12.

Internal Reference Low-Power Features

The ADC10 internal reference generator is designed for low power applications. The reference generator includes a band-gap voltage source and a separate buffer. The current consumption of each is specified separately in the device-specific datasheet. When REFON = 1, both are enabled and when REFON = 0 both are disabled. The total settling time when REFON becomes set is ￿ 30 ∝s.

When REFON = 1, but no conversion is active, the buffer is automatically disabled and automatically re-enabled when needed. When the buffer is disabled, it consumes no current. In this case, the band-gap voltage source remains enabled.

When REFOUT = 1, the REFBURST bit controls the operation of the internal reference buffer. When REFBURST = 0, the buffer will be on continuously, allowing the reference voltage to be present outside the device continuously. When REFBURST = 1, the buffer is automatically disabled when the ADC10 is not actively converting, and automatically re-enabled when needed.

The internal reference buffer also has selectable speed vs. power settings. When the maximum conversion rate is below 50 ksps, setting ADC10SR = 1 reduces the current consumption of the buffer approximately 50%.

18.2.4 Auto Power-Down

The ADC10 is designed for low power applications. When the ADC10 is not actively converting, the core is automatically disabled and automatically re-enabled when needed The ADC10OSC is also automatically enabled when needed and disabled when not needed. When the core or oscillator are disabled, they consume no current.

18-6 ADC10

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Texas Instruments MSP430x1xx manual Voltage Reference Generator, Internal Reference Low-Power Features
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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.