dsPIC® DSCs: Power of a DSP With the Simplicity of an MCU

Microchip’s dsPIC® Digital Signal Controllers (DSCs) have been in the market for nearly 20 years. The dsPIC DSCs have been focused on applications including motor control, digital power, advanced sensing and control, robust touch, embedded security, functional safety and various other high performance and robust designs.

The dsPIC DSCs have been designed with the main objective of giving a microcontroller (MCU) the power and features of a Digital Signal Processor (DSP) engine with the required architecture and the instruction set. These DSCs have come a long way and are now adaptive to the mainstr3eam real-time control applications and are suitable for diverse applications. The upcoming dsPIC33 DSCs will include enhanced features to support emerging technologies and their applications.

dsPIC33 DSCs—More Than an MCU

An MCU is ideal for applications requiring user and sensor interfaces. They can initialize and control applications, monitor inputs, react to interrupts and drive outputs through displays and actuators. But when it comes to processing real-time signals, an MCU needs more capabilities.

A DSC is a single-chip, embedded controller that seamlessly integrates the control attributes of an MCU with the computation and throughput capabilities of a DSP in a single core. Microchip’s dsPIC DSCs offer everything you would expect from a powerful controller: accelerated math operations, fast, sophisticated and flexible interrupt handling, and functional safety and security features. The dsPIC DSCs execute most instructions in a single cycle. Combine that with high instruction throughput and true DSP capabilities, such as single cycle multiply and zero overhead looping, and you have a very powerful MCU for your embedded control designs. Together with fast deterministic performance to address real-world design requirements and dsPIC DSCs include a rich set of application-specific peripherals to help you develop real-time control systems.

• The combination of high-resolution motor control Pulse-Width Modulators (PWMs) and very fast and accurate 12-bit Analog-to-Digital Converters (ADCs) with a DSP engine allows you to implement high-efficiency, high-precision, variable-speed, constant-torque, Proportional Integral (PI) control and Field Oriented Control (FOC) for a variety of motor control applications

• Switch Mode Power Supply (SMPS) PWMs, multiple high-speed ADCs, Programmable Gain Amplifiers (PGAs) and a Central Processing Unit (CPU) with fast and predictable interrupts enable the execution of tight control loops and powerful algorithms to maximize efficiency in digital power conversion applications at all load conditions

• With a high level of analog integration, dsPIC33 DSCs are well suited for advanced sensor interfacing and robust touch applications. These DSCs offer a high-performance Central Processing Unit (CPU) with a DSP engine for deterministic and real-time response

• Select DSCs offers 5V operation for better noise immunity and robustness

• With −40°C to 150°C operation (AEC-Q100 Grade 0 qualification), these DSCs are ideally suited for under-the-hood automotive designs

• Our broad portfolio of functional safety-ready and functional safety-compliant dsPIC33 DSCs offers integrated hardware safety features, Failure Modes, Effects and Diagnostic Analysis (FMEDA) reports, safety manuals and diagnostic software libraries to develop safety-critical applications meeting ISO 26262, IEC 61508 and IEC 60730 requirements

• dsPIC33 DSCs with integrated secure subsystem or any dsPIC33C DSCs can work together with the CryptoAuthentication and CryptoAutomotive security ICs to implement robust system-level security

Apart from the regular MCU capabilities, the DSP engine in the dsPIC DSCs include the following hardware design features to optimize DSP algorithm execution such as dual Address Generation Units, a Barrel Shifter, a Multiplier and adder, Dual Accumulators and Context Registers.

• The dsPIC architecture integrates the MCU and DSP functions using a modified Harvard Bus Architecture.  A combined instruction pipeline supports CPU instructions with up to three operands to optimize execution time.

• The heart of the DSP engine is a 40-bit ALU along with two 40-bit saturating accumulators. Assisting this is a bi-directional barrel shifter capable of shifting a 40-bit value up to 16-bit left or right in a single cycle. A hardware multiplier supports high speed arithmetic and logical operations.

• To support the MAC instructions and DSP algorithms with specific addressing modes, Dual Address Generation Unit (AGUs) are provided to speed up the process of data address computation, access and storage.

• Well defined single-cycle MAC instructions support filter, FFT and vector math operations. Optimized DSP routines are available as libraries in the XC-DSC compiler to reduce execution time.

• The Zero Overhead looping instructions from the hardware core eliminate the software dependency of looping and improve code performance speed.

• The context registers help in switching DSP functions at a faster pace while leveraging the benefits of fast deterministic interrupt responses and the flexible software stack overflow detection.    

The latest dsPIC DSCs are designed to offer performance up to 100 MHz, richly featured with peripherals including CAN-FD, Configurable Logic Cell (CLC), Touch Controller, a secure subsystem, Operational Amplifiers (OP-AMPs), Current Bias Generator (CBG), a Peripheral Trigger Generator (PTG) and more, connected through a high-speed peripheral bus.  The on-chip memory ranges from 32KB–1MB Flash for Program Memory and 8KB–128KB of RAM for Data Memory.

dsPIC Target Application Domains

Motor Control

dsPIC33 DSCs feature high-resolution PWM outputs with dedicated time bases and fast and highly accurate 12-bit ADCs along with a rich complement of other analog peripherals.  These peripherals are designed for motor control applications that require variable speed with constant torque and Field-Oriented Control (FOC) for top energy efficiency.  Listed are some of the peripheral features of the dsPIC33C DSCs which enables them to spin motors efficiently.

• High-resolution complementary PWM outputs with dead-time insertion and compensation, supporting independent, edge and center aligned operation modes

• Up to 24 channels of high-resolution PWMs enabling quad-motor control and/or integrated PFC for high-voltage applications

• Up to five very fast (3.5 MSPS) 12-bit ADCs, supporting up to 27 analog inputs, with highly accurate conversions (10.5 ENOB typical), along with built-in digital comparators, oversampling filters and multiple Sample-and-Hold (S&H) circuits

• Differential high-speed (15ns) analog comparators with integrated 12-bit Digital-to-Analog Converters (DACs) supporting automatic PWM shutdown upon over-current detection

• 3 high-bandwidth (20 MHz) Op-Amps with fast slew rates (40V/s) and low input voltage offset (1.5mV typical), or Programmable Gain Amplifiers (PGAs) for motor current gain circuits

• Hall sensor and optical (incremental) encoder rotor position feedback support (QEI Module)

• Tightly coupled PWMs, ADCs, Op-Amps or PGAs and Comparators support fast and predictable control loops without CPU involvement

• Dual Core DSCs optimize real-time responsiveness and enable easy software integration for multiple development teams, or teams located in diverse locations

• High level of analog integration provides a lower Bill of Materials (BOM) cost

Besides designing our dsPIC DSCs specifically for motor control, we provide a rich ecosystem of development boards, reference designs, software tools and application notes with code to enable rapid prototyping of motor control applications. Our worldwide motor control team provides expert localized customer support.