NORWOOD, Mass. Advocates think DSPs will do a better job of calculating motor acceleration/deceleration curves than microcontrollers. Thus, dedicated devices such as Analog Devices Inc.'s ADMC-401 are targeting high-end applications like industrial servo controls, machine tools, robotics and uninterruptible power supplies.
The ADMC401 integrates a 26-Mips ADSP-2171DSP core and a 12-bit simultaneous-sampling A/D converter on one chip. The device is among 20 DSPs optimized for specific motor-control applications that ADI intends to release this year, said Phil Davies, director of the company's Embedded Control Systems Group.
The device is optimized for speed, precision and control of ac induction motors, permanent-magnet synchronous motors, brushless dc motors and switched-reluctance motors in industrial applications that demand the highest level of processing power. It includes a pipeline 12-bit A/D converter with a multiplexed eight-channel input. The pipeline flash converts in less than 2 microseconds. Signal-to-noise ratio is greater than 70 dB.
Other on-chip peripherals include a separate encoder interface unit with programmable input filtering (for reading optical encoder disks on the motor shaft) and a 16-bit, three-phase pulse-width modulator. Separate power transistors will amplify the PWM output to drive the motor coils.
There are also 12 lines of programmable digital I/O, two auxiliary PWM outputs, a 16-bit watchdog timer, two 16-bit interval timers and a programmable interrupt controller that prioritizes peripheral interrupts.
The DSP core is an ADSP-2171 fixed-point version, code-compatible with the company's ADSP-21xx general-purpose DSP family and the ADMC3xx family of embedded DSP motor controllers. The ADMC401 includes on-chip program and data memory in addition to an external program and data bus for adding extra memory or other peripherals as needed.
Using algebraic C-language-like constructs, Analog Devices' fixed-point DSP cores
allow users to easily develop programs and applications, decreasing overall time-to-market. A software development kit-the ADMC401-ADVEVALKIT-sells for $395 and includes a Windows-based motion-control debugger.
Samples and advanced evaluation kits are available now. The ADMC401 comes in a 144-pin thin quad flat pack and is priced at $15 in high volumes.
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EETInfo No. 626