Z8 Encore! MC

Targets: Automotive, Computers & Peripherals, Consumer, Industrial, Motor Control

Zilog Z8 Encore! MC Block Diagram

The Z8 Encore! MC family targets brushless DC, brushed DC, stepper, universal, switch reluctance, and AC motor control applications. On-chip peripherals such as an optimized PWM module, a fast 2.5µs A/D converter with a time stamp, an op amp, and multiple communication engines make these devices suitable for brushless DC motors. With the over-current sense feature and fault input, designers can incorporate fast shutdown of the motor for anti-kick back or stall detection.

Zilog's microcontroller-based design offers developers the option to add complex and differentiating features through the 16-kbytes of on-board Flash memory and 17 general-purpose I/Os pins for incorporating a variety of new system functions. Another feature that the Z8 Encore! MC family offers is multiple, integrated communication peripherals such as I²C, SPI, UART and LIN.

The Z8 Encore! MC family is supported by a development kit, which includes Zilog's ZDS II IDE (integrated development environment) and a full ANSI C-compiler. Free software upgrades are available.

The Back EMF Sample Time Stamp is a patented applied function offering a configuration that ties two existing microcontroller blocks together to add functionality to the microcontroller. This feature replaces having a traditional microcontroller implementation of Back EMF sensing using an extra comparator and multiplexer, thus saving die area and PCB space. Replacing the DSP method by using an ultra-fast ADC and auto-sequencing to sample Back EMF, this feature can also be used for battery charging DV/DT measurement - ultimately eliminating the need for interrupt driven ADC timing and lowering microcontroller overheads. The on-chip integrated A/D converter with this 'Time Stamp' feature is coupled to the 3-Phase PWM output module, a feature that allows for accurate speed control.

The Over-Current Comparator is an application-specific feature integrated into the Z8 Encore! MC which eliminates the need for an external comparator. When the comparator is tied to the PWM module, safe shutdown is possible, even with the loss of the oscillator. The Current Sampling Amplifier is another patent-applied, function that eliminates Time-dependent Sampling of the motor current. This feature enhances motor performance and functionality without adding cost to the Bill of Material.

Zilog's DPLL (digital phase lock loop) control for motors runs as a timer-based interrupt service routine, and it does not require the motor to run open-loop at startup. The Back EMF signal is locked from the very onset of the start-up phase, without the need for initial placement of the rotor in a specific position. Performing this action results in a smooth increase in the motor speed, as well as nearly instantaneous reversal of direction of rotation on command.

In many applications, electrical noise generated by the motor can interfere with the microcontroller's operation. In the Z8 Encore! MC, the microcontroller uses a highly accurate Internal Precision Oscillator as the system clock source (one of a number of system clock options) to aid in noise reduction. Other key features include direct routing of the current sensing module to the PWM module, which enables a fast shutdown of the system during an over current fault.

Zilog offers full documentation and support online via data sheets, application notes, and flyers for various target-specific applications (such as HVAC, large appliances, small appliances).

A motor control-specific development tool suite is also available for the Z8 Encore! MC family that is a complete 'out-of-the-box' motor control implementation, including a BLDC motor, application board, ZDS II with full ANSI C-Compiler, motor control software code and an opto-isolated USB smart cable for debugging and programming. The opto-isolated USB smart cable is available as a stand-alone product, and is compatible with most Z8 Encore! and Z8 Encore! XP products. Zilog offers a high-end, ICE (in-circuit emulator) kit, which includes package adapters and event trace functions.

Parts featured within this family include the Z8FMC04, Z8FMC08 and Z8FMC16.