Central Processor Unit (CPU) Registers

You can invoke the bootstrap program options (except modes 0 and 8) at any time by setting the MA, MB, MC, and MD bits in the OMR and jumping to the bootstrap program entry point, $FF0000. Software can set the mode selection bits directly in the OMR. Bootstrap modes 1–7 and 9–F select different specific bootstrap loading source devices. For the bootstrap program to execute correctly in these modes, you must use the following data sequence when downloading the user program through an external port:

1.Three bytes that specify the number of (24-bit) program words to be loaded

2.Three bytes that specify the (24-bit) start address where the user program loads in the DSP56301 program memory

3.The user program (three bytes for each 24-bit program word)

Note: The three bytes for each data sequence are loaded least significant byte first.

When the bootstrap program finishes loading the specified number of words, it jumps to the specified starting address and executes the loaded program.

4.3Central Processor Unit (CPU) Registers

There are two CPU registers that must be configured to initialize operation. The Status Register (SR) selects various arithmetic processing protocols and contains several status reporting flag bits. The Operating Mode Register (OMR) configures several system operating modes and characteristics.

4.3.1Status Register (SR)

The Status Register (SR) (Figure 4-1) is a 24-bit register that indicates the current system state of the processor and the results of previous arithmetic computations. The SR is pushed onto the system stack when program looping is initialized or a JSR is performed, including long interrupts. The SR consists of the following three special-purpose 8-bit control registers:

νExtended Mode Register (EMR) (SR[23–16]) and Mode Register (MR) (SR[15–8]) —Thesespecial-purpose registers define the current system state of the processor. The bits in both registers are affected by hardware reset, exception processing, ENDDO (end current DO loop) instructions, RTI (return from interrupt) instructions, and TRAP instructions. In addition, the EMR bits are affected by instructions that specify SR as their destination (for example, DO FOREVER instructions, BRKcc instructions, and MOVEC). During hardware reset, all EMR bits are cleared. The MR register bits are affected by DO instructions, and instructions that directly reference the MR (for example, ANDI, ORI, or instructions, such as MOVEC, that specify SR as the destination). During processor reset, the interrupt mask bits are set and all other bits are cleared.

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DSP56301 User’s Manual

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Motorola DSP56301 user manual Central Processor Unit CPU Registers, Status Register SR
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DSP56301 specifications

The Motorola DSP56301 is a highly efficient digital signal processor, specifically engineered for real-time audio and speech processing applications. This DSP is part of Motorola's renowned DSP56300 family, which is recognized for its innovative features and outstanding performance in the realm of digital signal processing.

One of the main features of the DSP56301 is its ability to handle complex computations at high speeds. With a maximum clock frequency of 66 MHz, it delivers fast performance, enabling it to process audio signals in real time. The chip is built on a 24-bit architecture, which allows for high-resolution audio processing. This is particularly beneficial in applications such as telecommunications, consumer audio devices, and professional audio equipment, where precision is paramount.

The DSP56301 boasts a comprehensive instruction set that includes efficient mathematical operations, which are essential for digital filters and audio effects processing. One of the key innovations of this device is its dual data path architecture, which permits simultaneous processing of multiple data streams. This feature significantly enhances the device's throughput and responsiveness, making it suitable for demanding applications such as voice recognition and synthesis.

In terms of memory regions, the DSP56301 includes several on-chip memory categories, such as program memory, data memory, and a specialized memory for coefficients. The architecture's support for external memory expansion further increases its versatility, allowing designers to tailor systems to their specific requirements.

The DSP56301 implements advanced features such as a powerful on-chip hardware multiplier and accumulator, simplifying complex mathematical tasks and accelerating the execution of algorithms. Its flexible interrupt system enhances its capability to respond to time-sensitive operations, while the integrated serial ports facilitate efficient data communication with external devices.

Power consumption is also a vital characteristic of the DSP56301. It is designed with energy efficiency in mind, allowing for extended operation in battery-powered devices. The chip’s low power requirements are particularly advantageous in portable audio devices and other applications where energy conservation is crucial.

In conclusion, the Motorola DSP56301 is an exceptional digital signal processor that combines high processing power, flexibility, and efficiency. Its main features, advanced technologies, and robust architecture make it a top choice for developers seeking to create sophisticated audio and signal processing systems. With its enduring legacy in the industry, the DSP56301 continues to be relevant in a variety of modern applications, ensuring it remains a valuable tool for engineers and designers.
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