Temporary Accumulator T, Index register

CHAPTER 3 CPU

●Temporary Accumulator (T)

The temporary accumulator is an auxiliary 16-bit arithmetic operation register. It handles arithmetic operations using data in the accumulator (A). When arithmetic operations in the accumulator (A) are handled in word units (16 bits), data in the temporary accumulator is handled in word units. Otherwise, it is handled in byte units (8 bits). When arithmetic operations are handled in byte units, only the lower 8 bits (TL) in the temporary accumulator are used; the upper 8 bits (TH) are not used.

When an MOV instruction is used to transfer data into the accumulator (A), data stored in the accumulator is automatically transferred to the temporary accumulator before it is transferred. For data transfer in byte units, the upper 8 bits of the temporary accumulator (TH) does not change. The initial value of the temporary accumulator specified after the reset operation is undefined.

●Index register (IX)

The index register is a 16-bit register that stores an index address. The index register is used together with a 1-byte offset (-128 to +127). It generates a memory address for accessing data by adding a sign-extended offset to the index address. The initial value of the index register specified after the reset operation is undefined.

●Extra-pointer (EP)

The extra-pointer is a 16-bit register. Data in the extra-pointer is handled as the memory address for accessing data. The initial value of the extra-pointer specified after the reset operation is undefined.

●Stack pointer (SP)

The stack pointer is a 16-bit register that stores an address that is used to call an interrupt or subroutine, or to which a stack/recovery instruction makes a reference. While a program is being executed, the value of the stack pointer indicates the address of the latest data put in the stack. The initial value of the stack pointer specified after the reset operation is undefined.

●Program status (PS) register

The program status is a 16-bit control register. The upper 8 bits of the program status register is the register bank pointer (RP) used to indicate the address of a general-purpose register bank.

The lower 8 bits are the condition code register (CCR) that composes flags for indicating the CPU status. Because these 8-bit registers comprise the program status register, they cannot be accessed. (Only instructions MOVW A, PS and MOVW PS, A access the program status register.)

Note:

For details on how to use the dedicated register, see the F2MC-8L MB89600 Series Programming Manual.

F202RA, MB89202 specifications

The Fujitsu MB89202 and F202RA microcontrollers are part of the 16-bit microcontroller family, renowned for their robust performance and versatility in a variety of embedded system applications. These devices are tailored for high-efficiency operation across diverse industries, including automotive, consumer electronics, and industrial automation.

One of the main features of the MB89202 is its powerful CPU core, which operates at a clock speed of up to 20 MHz. This enables the microcontroller to perform complex calculations and consumer-grade applications seamlessly. The architecture is designed to handle multiple tasks effectively, making it suitable for real-time operations.

Memory capacity is a vital characteristic of the MB89202, featuring on-chip RAM and ROM configurations. The microcontroller can accommodate different memory variants, providing developers with flexibility in memory allocation based on their application requirements. This adaptability facilitates applications ranging from simple control systems to complex data processing tasks.

The F202RA variant extends the capabilities of the MB89202 by integrating advanced peripheral functions. It includes built-in timers, A/D converters, and serial communication interfaces, which are essential for interfacing with other hardware components or sensors. The availability of these peripherals reduces the need for additional external circuits, thus contributing to a more compact and cost-effective design.

In terms of power management, the MB89202 series employs advanced power-saving technologies. The microcontroller offers various low-power modes, enabling devices to conserve energy during idle times, making it highly suitable for battery-operated applications. This characteristic not only enhances the efficiency of devices but also extends their operational lifespan.

Moreover, the Fujitsu MB89202 series incorporates robust protection features, including watchdog timers and failure detection mechanisms. These safety features ensure reliable operation in critical systems, making them a preferred choice in applications where failure is not an option.

The MB89202 and F202RA microcontrollers also support a range of development tools and environments, including integrated development environments (IDEs) and software libraries, which facilitate rapid application development. With these tools, developers can efficiently prototype, debug, and optimize their applications.

In summary, the Fujitsu MB89202 and F202RA microcontrollers stand out with their efficient performance, extensive memory options, integrated peripherals, and power-saving capabilities, making them ideal for a wide array of embedded applications. Their reliability and robustness further enhance their attractiveness for designers seeking advanced microcontroller solutions.

Fujitsu MB89202 manual Temporary Accumulator T, Index register, Extra-pointer EP, Stack pointer SP

Models: F202RA MB89202