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Motorola DSP56301 user manual Byte Format LSB/MSB for the Transmitter, Flags

Models: DSP56301

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Operating Modes: Normal, Network, and On-Demand

7.4.8Byte Format (LSB/MSB) for the Transmitter

Some devices, such as CODECs, require a MSB-first data format. Other devices, such as those that use the AES–EBU digital audio format, require the LSB first. To be compatible with all formats, the shift registers in the ESSI are bidirectional. You select either MSB or LSB by programming CRB[SHFD].

νIf CRB[SHFD] is cleared, data is shifted into the receive shift register MSB first and shifted out of the transmit shift register MSB first.

νIf CRB[SHFD] is set, data is shifted into the receive shift register LSB first and shifted out of the transmit shift register LSB first.

7.4.9Flags

Two ESSI signals (SC[1–0]) are available for use as serial I/O flags. Their operation is controlled by the SYN, SCD[1–0], SSC1, and TE[2–1] bits in the CRB/CRA.The control bits OF[1–0] and status bits IF[1–0] are double-buffered to and from SC[1–0]. Double-buffering the flags keeps the flags in sync with TX and RX.

The SC[1–0] flags are available in Synchronous mode only. Each flag can be separately programmed. The SC0 flag is enabled when transmitter 1 is disabled (TE1 = 0). The flag’s direction is selected by the SCD0 bit. When SCD0 is set, SC0 is configured as output. When SCD0 is cleared, SC0 is configured as input. Similarly, the SC1 flag is enabled when transmitter 2 is disabled (TE2 = 0), and the SC1 signal is not configured as the transmitter 0 drive-enabled signal (Bit SSC1 = 0). The direction of SC1 is determined by the SCD1 bit. When SCD1 is set, SC1 is an output flag. When SCD1 is cleared, SC1 is an input flag.

When programmed as input flags, the value of the SC[1–0] bits is latched at the same time as the first bit of the received data word is sampled. Once the input is latched, the signal on the input flag signal (SC0 and SC1) can change without affecting the input flag. The value of SC[1–0] does not change until the first bit of the next data word is received. When the received data word is latched by RX, the latched values of SC[1–0] are latched by the SSISR IF[1–0] bits, respectively, and can be read by software.

When they are programmed as output flags, the value of the SC[1–0] bits is taken from the value of the OF[1–0] bits. The value of OF[1–0] is latched when the contents of TX transfer to the transmit shift register. The value on SC[1–0] is stable from the time the first bit of the transmit data word transmits until the first bit of the next transmit data word transmits.

Software can directly set the OF[1–0] values, allowing the DSP56301 to control data transmission by indirectly controlling the value of the SC[1–0] flags.

Enhanced Synchronous Serial Interface (ESSI)

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Motorola DSP56301 user manual Byte Format LSB/MSB for the Transmitter, Flags
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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.