Hardware Multiplier Operation

7.2.4Indirect Addressing of RESLO

When using indirect or indirect autoincrement addressing mode to access the result registers, At least one instruction is needed between loading the second operand and accessing one of the result registers:

; Access multiplier results with indirect addressing

MOV

#RESLO,R5

; RESLO address in R5 for indirect

MOV

&OPER1,&MPY

; Load 1st operand

MOV

&OPER2,&OP2

; Load 2nd operand

NOP

 

; Need one cycle

MOV

@R5+,&xxx

; Move RESLO

MOV

@R5,&xxx

; Move RESHI

7.2.5Using Interrupts

If an interrupt occurs after writing OP1, but before writing OP2, and the multiplier is used in servicing that interrupt, the original multiplier mode selection is lost and the results are unpredictable. To avoid this, disable interrupts before using the hardware multiplier or do not use the multiplier in interrupt service routines.

; Disable interrupts before using the hardware multiplier

DINT

; Disable interrupts

NOP

;

Required for DINT

MOV

#xxh,&MPY ;

Load 1st operand

MOV

#xxh,&OP2 ;

Load 2nd operand

EINT

;

Interrupts may be enable before

 

;

Process results

7-6

Hardware Multiplier

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Texas Instruments MSP430x1xx manual Indirect Addressing of Reslo, Using Interrupts
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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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