The TMS320VC5503 fixed-point digital signal processor (DSP) is based on the TMS320C55x DSP generation CPU processor core. The C55x? DSP architecture achieves high performance and low power through increased parallelism and total focus on reduction in power dissipation. The CPU supports an internal bus structure that is composed of one program bus, three data read buses, two data write buses, and additional buses dedicated to peripheral and DMA activity. These buses provide the ability to perform up to three data reads and two data writes in a single cycle. In parallel, the DMA controller can perform up to two data transfers per cycle independent of the CPU activity.

The C55x CPU provides two multiply-accumulate (MAC) units, each capable of 17-bit × 17-bit multiplication in a single cycle. A central 40-bit arithmetic/logic unit (ALU) is supported by an additional 16-bit ALU. Use of the ALUs is under instruction set control, providing the ability to optimize parallel activity and power consumption. These resources are managed in the Address Unit (AU) and Data Unit (DU) of the C55x CPU.

The C55x DSP generation supports a variable byte width instruction set for improved code density. The Instruction Unit (IU) performs 32-bit program fetches from internal or external memory and queues instructions for the Program Unit (PU). The Program Unit decodes the instructions, directs tasks to AU and DU resources, and manages the fully protected pipeline. Predictive branching capability avoids pipeline flushes on execution of conditional instructions.

The 64K bytes of on-chip memory on TMS320VC5503 is sufficient for many hand-held appliances, portable GPS systems, wireless speaker phones, portable PDAs, and gaming devices. Many of these appliances typically require 64K bytes or smaller amount of on-chip memory and need to operate in standby mode for more than 60% to 70% of the time. For applications that require more than 64K bytes of on-chip memory but less than 128K bytes of memory, Texas Instruments (TI) offers the TMS320VC5507 device, which is based on the TMS320C55x DSP core.

The general-purpose input and output functions and the 10-bit A/D provide sufficient pins for status, interrupts, and bit I/O for LCDs, keyboards, and media interfaces. The parallel interface operates in two modes, either as a slave to a microcontroller using the HPI port or as a parallel media interface using the asynchronous EMIF. Serial media is supported through three McBSPs.