TI has announced a new, highly integrated DSP core optimized for use in high-volume, wireless communications applications such as digital cellular phones, pagers, personal digital assistants (PDAs), and wireless modems.
The core, the TMS320C54x, was designed to support worldwide wireless communications standards such as Global System for Mobile Communications (GSM), IS-54/136, PDC, CDPD, and IS-95 standards. It is aimed at maximizing performance while enabling low-power implementation of various wireless systems. Some of the core's key features include a Viterbi Accelerator, four internal buses and dual address generators, a 40-bit adder with two 40-bit accumulators, and single-cycle normalization with exponential encoding.
"By using inputs from key wireless customers to define the core's features, the core provides increased performance, support for parallel operations, and low power dissipation per function," said Thomas Brooks, TI's marketing manager for wireless communications. "This creates a more efficient way to implement CELP vocoders and other key digital communications functions."
Other core features include 16-bit signed or 17-bit unsigned multiplication with rounding and saturation in one instruction cycle, a 40-bit ALU with a dual 16-bit configuration capability, and eight auxiliary registers.
Based on this core, TI has announced two new DSPs, the TMS320C541 and TMS320C542, which are designed for wireless communications terminals and base stations, respectively. The 'C541 provides 28K words of ROM and 5K words of RAM on-chip, while the 'C542 includes a host-port interface and a buffered-serial port with 2K words of ROM and 10K words of RAM on-chip. Both operate at either 2.7 V or 5 V.
According to Gilles Delfassy, general manager of TI's worldwide wireless communications business unit, the 'C54x DSPs require an average of only 12.7 MIPS to implement full-rate GSM. "With 50 total CPU MIPS available, the remaining MIPS can be devoted to the variety of tasks traditionally handled by ASICs or microcontrollers," said Delfassy. "The result is an overall reduction in system cost, with less power consumption and battery drain due to reduced chip count."
TI is also licensing fully-tested, full-rate GSM software modules that utilize the features of the 'C541 and 'C542 and also comply with European Telecommunications Standards Institute (ETSI) specifications. The GSM modules perform voice coding and decoding, demodulation, encryption, channel coding and decoding, as well as other functions required for GSM systems such as interrupt handling and control.
Along with the 'C541 and 'C542, TI offers the capability to create custom devices around the 'C54x DSP core. TI's customizable DSP (cDSP) technology allows single-chip integration of the 'C54x DSP core with microcontroller cores, analog functions, additional memory, peripherals, and logic gates.
The 'C541 is currently available, at the suggested resale price of U.S. $23 each (250K quantity) in 100-pin thin-quad flat pack (TQFP) packages. The 'C542, in 128-pin TQFP packages, is now sampling with production planned for the fourth quarter of 1995. The suggested resale price for the 'C542 is U.S. $28 each (250K quantity). Both parts are available directly from TI.