FROM EDN EUROPE: Hybrid DSP/µPs meet low-cost BoM targets

Freescale has extended the scope of its digital signal controller devices—microcontrollers that have a combined control and signal processing function set—with a range of very low-cost, flash-based parts. Designers can use them in motor control, domestic appliance, power supply and consumer product applications. In the 56800 family, these chips have part numbers in the MC56F8000 format. They use the 56800E core (which includes single-cycle multiply-accumulate) and are housed in 32-pin packages giving up to 26 I/Os. They offer the 6-output PWM controller used elsewhere in the DSC range, running at 96 MHz (three times the basic clock of 32 MHz) to give fine resolution on the PWM output for precise motor control.

There is a dual-channel analogue-to-digital converter with conversion time of 1.125 μsec, that can be synchronised with the PWM stage. External parts count can be minimised by use of an internal oscillator that is stable to ±2.5% over the industrial temperature range, with parts that operate over the full automotive range to be added at a later stage. Other peripherals include four timers and a range of interfaces. Any peripheral that is not in use can have its external pins re-allocated as I/O.

Development support is provided via the Metrowerks CodeWarrior suite, with a low-cost development kit ($100) and a free version of the software available by download. The free version is limited to 16k of code space, but the smallest parts in the family have a flash memory block of that size and so can be programmed with the free download. Support includes free downloadable reference designs in a number of application areas. The software also offers a library of pre-compiled software routines for functions that include motor control, communications, DSP operations and mathematics. The chips will be priced at $2.99 (10,000).

Freescale, www.freescale.com.