FROM EDN EUROPE: DSL router-on-chip targets home networks

For a 25% reduction in bill of materials, you can build a home gateway that accepts a DSL connection and directly connects to Ethernet; by adding a four-port Ethernet switch or a wireless-LAN access point, you can configure a complete DSL gateway. The key part is Texas Instruments' AR7, which incorporates a MIPS 32-bit core, a DSP-based transceiver, and an ADSL analogue front end with line drivers, receivers, and power management. On-chip memory comprises 4 kbytes of ROM and RAM, with a full flash/SDRAM controller for off-chip memory; two Ethernet MACs, one with a PHY, manage eight transmit and eight receive queues. The MIPS RISC processor runs TI's TurboDSL; the chip implements a "packet accelerator," dynamic adaptive equalization, and support for ADSL2+, all aiming to extend service coverage of DSL services and to pave the way for higher speed services. "Packet acceleration" is TI's phrase for managing throughput so that the packet rate that the DSL link achieves is what the host machine actually sees. AR7 runs on Linux and VxWorks operating systems and comes with a complete network-software package.

In a separate announcement, TI said that when it ports its TMS32064x DSP processors to 90-nm fabrication technology, simulations show that the architecture will run at 1 GHz—making the DSPs the first to achieve this speed. Running a DSP with an internal 1-GHz clock is not the same as running a CISC processor at gigahertz speeds. With the CISC device, many more internal clock cycles execute between typical external accesses to the chip; with a gigahertz DSP, the circuitry around the processor does not decouple from the on-chip clock to the extent it does with a CISC device. TI says it will offer support to deal with this situation from a design point of view through a combination of faster interfaces, memory-access techniques, and the use of co-processors. Expect an announcement for the 1-GHz product early in 2004.

Texas Instruments, +49 8161 803311, www.ti.com.