The first single-DSP solutions for modified cellular telephone standards, such as half-rate Global System for Mobile Communications (GSM), were introduced in September by Texas Instruments. The two new devices can support a variety of international communications standards-such as GSM, IS-54B, IS-136, IS-95 and Personal Digital Cellular (PDC) -- and help clear the way for simultaneous voice and data transmission.
The devices, members of TI's TMS320C54x generation of DSPs, are known as the 'C545 and 'C546. Both feature core architecture optimized for wireless communications along with the powerful memory and added peripherals needed for next-generation cellular phones.
Until now, complex half-rate cellular communications standards required two DSPs, along with memory enhancements, to function effectively in cellular telephone handsets. With performance of 50 Million Instructions Per Second (MIPS) and both RAM and ROM on board, the 'C545 and 'C546 can cut that to one chip. Because they are programmable, the devices can accommodate accepted standards--such as IS-54B, IS-136, PDC and GSM--as well as emerging half-rate variations.
Half-rate applications of existing standards allow a service provider to pack twice as many telephone conversations into available bandwidth.
Peripherals built into the chips also help the new devices meet the requirements of cellular telephones. An auto-buffered serial port permits off-loading the CPU, leaving more MIPS available for new features. The host port interface (HPI) speeds communication with the rest of the system. The 'C545 includes both peripherals. The 'C546 serves equipment makers who need the auto-buffered serial port but not the HPI.
TI's new devices can operate at either 2.7 or 5 V and include power-down modes that can cut power dissipation to as little as 1 mW. And like other members of TI's TMS320C54x DSPs, they include hard-wired Viterbi accelerators that reduce Viterbi "butterfly update" significantly. The entire generation is supported by comprehensive hardware and software development tools to help reduce design time and get new products and features to the market faster.
The entire generation is supported by comprehensive hardware and software development tools to help reduce design time and get new products and features to the market faster.
TI's TMS320C545 and TMS320C546 devices currently are sampling and will become available in production quantities in this quarter. Neither device is available through distribution.
TMS320C545 128-pin TQFP $28 TMS320C546 100-pin TQFP $26
Suggested resale pricing in U.S. dollars in 250K quantities.
October 1995, vol. 12, no. 7