Bit, Byte, Word and String Addressing

is a string of bytes. The length of the byte string is stored in the string register (STR). To define the length of a string, the STR register should hold the length of the string minus 2. For example, if the length of a byte string is 10, then STR should be 8. A byte string address can be even or odd. Byte string data is fetched from the lower address (starting address) one byte at a time to consec- utive addresses.

NOTE: Data Memory Access

Data memory access (RAM) is always accessed with byte addresses. Pro- gram memory (ROM) is accessed with 17-bit words. Rx registers autoincre- ment (or autodecrement) by 1 for byte addressing, by 2 for word addressing, or by the length of the string in bytes if Rx++ (or Rx± ±) is used.

Word and Word string addresses: One data memory word is composed of two consecutive bytes. A word address is always an even byte address and the least significant bit of the byte address is assumed to be zero. Instructions that operate on words have internal hardware which increments the byte ad- dress appropriately to load the two consecutive bytes in one clock cycle. To use an absolute word address, the address should be multiplied by 2. A word- string is a string of consecutive words. Like a byte-string, word-strings use the STR register to define the string length. Word-strings always start at an even byte address. When string instructions are used, words are fetched from the first word-string memory location to consecutive addresses. The word address is the data memory address in bytes. This is obtained by multiplying the byte address by two.

Figure 4±3. Data Memory Organization and Addressing

Global

flags

Relative

flags

Flag addresses²

0000h

0001h

0002h

0040h

0041h

nnnn

17th Bit

17th Bit

17th Bit

17th Bit

17th Bit

17th Bit

Data memory

 

1 Word

Data memory

address (even)

 

address (odd)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0001h

0000h

 

 

MS Byte

 

 

 

LS Byte

 

 

0002h

 

 

 

 

 

 

 

 

0003h

 

 

MS Byte

 

 

 

LS Byte

 

 

0004h

 

 

 

 

 

 

 

 

0005h

 

 

MS Byte

 

 

 

LS Byte

 

 

 

 

 

 

 

 

 

 

 

nnnn+1

 

 

 

 

 

 

 

 

nnnn

 

 

MS Byte

 

 

 

LS Byte

 

 

 

 

 

 

 

 

 

 

 

 

 

Note: Word address is data memory address (or byte address) divided by 2.

²Flag address always accesses the 17th bit of 17 bit wide data word in data memory.

Assembly Language Instructions

4-45

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Texas Instruments MSP50C614 manual ±3. Data Memory Organization and Addressing
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MSP50C614 specifications

The Texas Instruments MSP50C614 is a microcontroller that belongs to the MSP430 family, renowned for its low power consumption and versatile functionality. Primarily designed for embedded applications, this microcontroller is favored in various industries, including consumer electronics, industrial automation, and healthcare devices.

One of the standout features of the MSP50C614 is its ultra-low power technology, which enables it to operate in various power modes. This makes it ideal for battery-powered applications, where energy efficiency is crucial. The MSP430 architecture allows for a flexible power management system, ensuring that energy is conserved while providing robust performance.

The MSP50C614 is equipped with a 16-bit RISC CPU that delivers high performance while maintaining low power usage. With a maximum clock frequency of 16 MHz, it can execute most instructions in a single cycle, resulting in swift operation and responsive performance. This microcontroller also comes with a generous flash memory capacity, allowing developers to store large amounts of code and data conveniently.

In terms of peripherals, the MSP50C614 is highly versatile. It features a range of digital and analog input/output options, including multiple timers, GPIO ports, and various communication interfaces like UART, SPI, and I2C. This extensive set of peripherals allows for seamless integration with other components and simplifies the design of complex systems.

The integrated 12-bit Analog-to-Digital Converter (ADC) stands out as a valuable characteristic of the MSP50C614. This feature enables the microcontroller to convert physical analog signals into digital data, making it particularly useful for sensing applications and real-time monitoring.

Another noteworthy technology employed in the MSP50C614 is its support for low-voltage operations. With a broad supply voltage range, this microcontroller can function efficiently in diverse environments and is suitable for low-power applications, enhancing its practicality.

Moreover, Texas Instruments provides software support in the form of Code Composer Studio and various libraries that make it easier for developers to program and utilize the MSP50C614 effectively.

In summary, the Texas Instruments MSP50C614 microcontroller is a powerful, low-power solution equipped with the features and technologies necessary for efficient operation in a wide array of applications. Its blend of performance, flexibility, and energy efficiency makes it a popular choice among engineers and designers looking to create innovative, sustainable designs in the rapidly evolving tech landscape.
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