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 dspZONE Products for the week of December 17, 2007
Microchip Technology Says…
Tiny Low Cost Digital Signal Controllers Get More Flash Memory
Six New dsPIC33F Low Pin Count Digital Signal Controllers Feature up to 32 kbyte Flash Memory; Packages as Small as 6 x 6 mm
Microchip Technology Inc., a leading provider of microcontroller and analog semiconductors, today announced an expansion of its low pin count 16-bit Digital Signal Controller (DSC) portfolio with the addition of three dsPIC33F General Purpose Family members and three dsPIC33F Motor Control/Power Conversion Family DSCs, which offer increased memory options for a range of applications including smart sensor processing, advanced motor control, lighting and power inverters.
The new General Purpose DSCs feature 16 or 32 Kbytes of Flash memory with 28- or 44-pin packages and provide a pin- and code-compatible migration path for PIC24 microcontrollers. The devices also feature an on-chip Analog-to-Digital-Converter (ADC), with up to 1.1 Msps, and serial interfaces such as I2C, SPI and UART. These DSCs are expected to be popular for a variety of embedded applications where high performance and small footprint are key requirements.
The three dsPIC33F Motor Control Family DSCs add a motor-control PWM with two independent clock sources for advanced motor control or inverter algorithms -- as well as active power factor correction -- using a single DSC. This on-chip PWM peripheral is also designed for power-conversion and lighting applications. They also include a quadrature encoder interface for sensor-based motor applications. These devices provide an excellent platform for advanced motor control algorithms, such as Field-Oriented Control (FOC) -- bringing the next level of high performance, low noise and power efficiency to motor control applications. (Microchip’s FOC source code can be downloaded for free, via Application Note AN1078.)
Both the General Purpose and Motor Control DSCs also feature Peripheral Pin Select, which allows designers to remap digital I/O to optimize board layout -- enabling smaller boards, less noise and the use of a lower pin count DSC.
“The unique combination of 32 Kbytes of Flash memory, DSP capability, low cost, and the industry’s smallest DSC package creates powerful possibilities for today’s embedded designers to push their products a step ahead of their competition,” said Sumit Mitra, vice president of Microchip’s Digital Signal Controller Division. “We have developed a number of basic and advanced libraries to aid time to market and to permit DSP-enabled features to be added without full immersion in DSP technology.”
Microchip offers powerful applications libraries that can be downloaded from Microchip’s Web site for free for evaluation and development. For production, libraries are either free or low cost, and without royalties. Library downloads include speech processing, noise reduction, motor control, advanced security, connectivity, file management, and common math and DSP routines. Microchip also offers low-cost visual tools for designers who wish to incorporate digital filters, tune parameters in real time and initialize peripherals.
Additional key features include the following:
Both Families
- 40 MIPS performance in 6x6 mm packages
- 32 or 16 Kbytes of Flash and 2 Kbytes of RAM
- 1 UART, 1 SPI and 1 I2C Port
dsPIC33FJ32GP General Purpose Family
- ADC w/ up to 13 channels, and user-selectable 10-bit or 12-bit mode
- (10-bit mode enables simultaneous sampling, eliminating lag time between samples)
dsPIC33FJ32MC Motor Control/ Power Conversion Family
- ADC w/ up to 9 channels, and user-selectable 10-bit or 12-bit mode
- (10-bit mode enables simultaneous sampling, eliminating lag time between samples)
Development Support
In addition to the aforementioned software libraries, both families are supported by the full complement of tools that are common to all of Microchip’s controllers, including the free MPLAB Integrated Development Environment with its Visual Device Initializer component, which graphically assists designers in mapping pins and initializing code for the on-chip Peripheral Pin Select pin-mapping function. The MPLAB C30 C compiler provides industry-leading code densities, along with math and peripheral libraries. For emulation and debugging, Microchip offers the full-featured MPLAB REAL ICE tool and the low-cost MPLAB ICD 2 tool. Finally, the 16-bit 28-pin starter board (part # DM300027) can be used for development with any of Microchip’s 28-pin 16-bit microcontrollers and DSCs, while the 44-pin family members are supported with a plug-in module for the Explorer 16 Development Board (part # DM240001).
EN-Genius Says…
Even before Microchip expanded their memory capacity, their slick little digital signal controllers were a bargain that posed some of the only credible competition to TI’s C2000 DSC family. For two-and-a half-bucks and a handful of milliwatts, they enable designers to deliver sophisticated filtering, analysis, and waveform generation capabilities in even the humblest applications. Now, by cramming up to 32 kbyte of Flash storage in the same tiny 6 mm x 6 mm QFN form factor, they’ve given those developers a chance to get even more creative, as well as giving TI good cause to cast a nervous eye in the rear-view mirror.
Microchip dsPICs can take especially good advantage of the extra program memory since their modified Harvard-style architecture can also use it to store data and lookup tables. They’ve also made the memory smarter with the addition of their CodeGuard technology to protect against IP theft. Put simply, it enables selected segments of code to be locked up against modification, or even reading by anything but the processor itself. Microchip claims that the memory lock-down logic has been hardened against all the common hacker tricks used to pry loose code from embedded systems. Besides the obvious protection it affords a product out in the field, it could also be very valuable for protecting an OEM against hacking or cloning of its products by its customers. A manufacturer offering a motor controller, or other industrial control board, could secure its own library of proprietary value-add software while allowing customers and 3rd-party developers to use them to build their own custom applications. The same protected segments can also be used to store encryption keys and algorithms to allow for secure upgrades and data exchanges.
If you’re unfamiliar with the dsPIC (as I was until recently), a short tour of its architecture might be helpful to get an idea of how they manage to get much useful work out of such a small, low-cost device. It combines a traditional ALU and RISC-like instruction set (nicely compatible with their standard PIC products) with a fully-functional MAC that does the same kinds of single-cycle operations found on larger DSPs. In addition, the processor’s instruction set has been structured to conserve program memory by minimizing the number of instructions required to accomplish most common functions.
One of the ways Microchip is able to squeeze much more work out of the MAC’s modest clock speed is by surrounding it with a nice assortment of simple hardware accelerators (like a barrel shifter and bit address reversing) to handle common instruction-intensive tasks in a single clock cycle -- often parallel with another MAC operation. As with most of Microchip’s other Flash-based processors, they use a combination of so-called fast Flash technology and a simple pre-fetch cache to eliminate the need for the long pipeline normally required to help the memory keep up with the processor. They also use some clever fast looping logic that helps accelerate repetitive calculations by taking the loop decision outside of the processor and into a hardware register.
 I really appreciate the fact that Microchip has gone the extra mile to offer reconfigurable I/O pin assignments on its devices. Although it’s somewhat of a necessity given the fact that there are so many peripheral and I/O connections squeezed into the reduced pin count package, it’s impressive that they’ve turned a potential bug into an important feature. The processor on-chip crossbar switch allows you to multiplex nearly any combination of peripheral functions onto a physical I/O connection -- a feature that can also simplify layout and, in some cases, save PCB layers.
With energy efficiency being such a hot topic these days, it’s exciting to contemplate the many green power applications that these inexpensive, compact devices lend themselves to. As the release above explains, the controllers come with different complements of peripherals to serve as a general-purpose machine and one specifically provisioned for motor control. The motor control variants include PWM waveform generation logic and quadrature encoder circuits that cut the number of external components required to implement highly-efficient variable-speed drive systems for induction motors. The same circuitry can also support more modern (and efficient) motors such as sensorless BLDC and permanent magnet (PMSM) designs. This makes it a great candidate for motor control in appliances, HVAC, and sewing machines. Microchip reports their controllers’ precision and efficiency is making them popular for controlling the sophisticated motors used in high-performance electric model airplanes. Other variants are available with a CAN Bus and an extended industrial temperature range that allows them to be used in internal combustion control systems and sensor integration in engine control systems.
Power consumption ranges from 25 - 80 mA at 5 V and even lower for their 3 V parts.
The dsPIC33FJ32GP and dsPIC33FJ32MC families consist of three members each, all in production priced at $2.51 and $2.47, respectively, in 10-k piece lots. The dsPIC33FJ32GP202 and dsPIC33FJ32MC202 are available in SDIP-28, SOIC-28 and QFN-28. The dsPIC33FJ32GP204, dsPIC33FJ32MC204, dsPIC33FJ16GP304 and dsPIC33FJ16MC304 are available in TQFP-44 and QFN-44. packages.
Product Page dsPIC33FJ32GP202
Product Page dsPIC33FJ32MC202
Product Page dsPIC33FJ32GP204
Product Page dsPIC33FJ32MC204
Product Page dsPIC33FJ16GP304
Product Page dsPIC33FJ16MC304
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