Sensorless Brushless DC Motor Control with the Z8FMC16100 MCU

Transcription

1 Application Note MultiMotor Series Sensorless Brushless DC Motor Control with the Z8FMC600 MCU AN Abstract This MultiMotor Series application note investigates the closed-loop control of a -phase brushless direct current (BLDC) motor using a Z8FMC600 MCU. Zilog s Z8FMC600 Series of microcontrollers is designed specifically for motor control applications and, with this MultiMotor Series, features an on-chip integrated array of application-specific analog and digital modules using the MultiMotor Development Kit. The result is fast and precise fault control, high system efficiency, on-the-fly speed/torque and direction control, as well as ease of firmware development for customized applications. This document further discusses ways in which to implement a sensorless feedback control system using a Phase-Locked Loop with back-emf sensing. The results are based on using a MultiMotor MCU Module equipped with a Z8FMC600 MCU, a -phase MultiMotor Development Board, and a -phase, VDC, 0 W, 00 RPM BLDC motor. Note: Features The source code file associated with this application note, AN070-SC0, is available free for download from the Zilog website. This source code has been tested with version of ZDS II for Z8 Encore! MCUs. Subsequent releases of ZDS II may require you to modify the code supplied with this application. The power-saving features of this MultiMotor Series application include: Smooth motor startup with reduced starting current Sensorless (back-emf) control using Phase-Locked Loop feedback Microcontroller-based overcurrent protection Selectable speed or torque control Selectable control of motor direction UART Interface for PC control LED to indicate a fault condition Discussion Z8FMC600 Series Flash microcontrollers are based on Zilog s advanced 8-bit ez8 CPU core. These Z8FMC600 devices set a standard of performance and efficiency, with most instructions using only 00 ns. Up to 6 kilobytes of internal Flash memory are accessible by the ez8cpu, and as many as 5 bytes of internal RAM provide storage of data, variables and stack operations. Figure on page displays a block diagram of the Z8FMC600 MCU architecture. AN Page of

2 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU In each of the Z8FMC600 products, the novel device architecture allows for realization of a number of enhanced control features: Time Stamp for Speed Control Integrated Operational Amplifier Multi-Channel PWM Timer Time Stamp for Speed Control Most microcontrollers use at least one dedicated comparator to detect the zero crossing of the input AC voltage signal so that the output driving pulses can be synchronized and adjusted to properly regulate motor speed. An alternative approach based on the Z8FMC600 MCU eliminates the requirement for this comparator by instead employing an analog-to-digital converter (ADC) in conjunction with a timer. In such a scenario, the ADC samples the BEMF voltage, with the timer running in the background. When the ADC samples the BEMF voltage zero crossing, it reads the timer count and writes the result to a register. This timer count becomes the commutation frequency, which is a function of the BEMF zero-crossing magnitude samples. The results of these BEMF samplings also feed into the ADC speed demand function to adjust the motor s speed by applying the appropriate PWM values to the phase voltages with a PLL closed loop. This time stamp approach results in a very simple and cost-effective solution for smooth operation of the motor in a steady state. Integrated Operational Amplifier Appliance controllers almost invariably monitor motor speed by sensing the current through the windings, using sensor and sensorless techniques in conjunction with the ADC. Ordinarily, sampling instances by the ADC are synchronized by the MCU. With this process, an external operational amplifier is often used to convert the current signal to a voltage signal; the ADC next samples the voltage signal and outputs the result to the processor. The processor then synthesizes the PWM outputs to control motor speed. In the case of the Z8FMC600 MCU, an on-chip integrated operational amplifier eliminates the requirement for an external component, thereby reducing overall system cost. Multi-Channel PWM Timer The Z8FMC600 MCU features a flexible PWM module with three complementary pairs or six independent PWM outputs supporting deadband operation and fault protection trip input. These features provide multiphase control capability for a variety of motor types and conduct safe operation of the motor by ensuring immediate shutdown of the PWM pins during a fault condition. AN Page of

3 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Analog Supply and Reference Digital Supply UART with LIN and IrDA Interrupt Control I C Master/Slave Reset Control 8 Port A SPI Watch-Dog Timer Comparator RC Oscillator Operational Amplifier Internal Precision Oscillator Fault Shutdown Oscillator Control Internal/External 8-Channel Multiplexer 8 Port B Sample and Hold ez8 0 MHz CPU A/D Converter Debugger Port C 6-Bit Counter/ Timer/PWM Register File (RAM) 5B x 8 6 -Bit PWM Module for Motor Control Flash Program Memory Up to 6K x 8 Figure. The Z8FMC600 MCU Architecture AN Page of

4 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Theory of Operation In a brushless DC motor, the rotor is comprised of permanent magnets, while the stator windings are similar to those in poly-phase motors. For a detailed discussion of BLDC motor fundamentals, as well as closed-loop control using sensorless techniques, refer to the Motor Control Electronics Handbook by Richard Valentine, McGraw-Hill, NY, 998. In sensor-based control applications, the Hall elements are integrated, and are used to detect the position of the rotor for drive synchronization. In contrast, sensorless control employs the detection of back-emf signals, which are generated (induced) by the rotating fields in the nonenergized phase windings to synchronize the timing of the control loop. A block diagram of the BLDC motor control system based on the Z8FMC600 MCU is shown in Figure. At any given instance in a -phase commutation arrangement, only two phases are energized. The back-emf voltage is, in turn, generated in the nonenergized phase winding, and the zero crossing of this induced voltage is detected for synchronization of the subsequent closed-loop control events. As discussed earlier, the innovative time stamp feature of the Z8FMC600 MCU provides for robust, efficient implementation of this critical sensing function without the requirement for an additional comparator. Figure.. A -Phase BLDC Motor Control System AN Page of

5 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU The algorithm for back-emf sensing is based on an implementation of a Phase-Locked Loop (PLL), which is described in Appendix C. Back-EMF Sensing Phase-Locked Loop on page 8. This algorithm is especially advantageous during startup, resulting in a very smooth increase in the motor speed, as well as a nearly-instantaneous reversal of direction of the rotation on command, as outlined below. With a conventional approach during the start-up sequence, power is applied to the windings to place the rotor in a known starting position, followed by commutation and the start of back-emf sensing and control. In contrast to the traditional approach, the PLL-based approach implemented with this application makes it possible to lock the back-emf signal from the onset of the start-up phase without the requirement for initial placement of the rotor in a specific position. Moreover, this approach significantly reduces any erratic movement of the motor during startup, or even a reversal of direction. During normal operation following the start-up period, phase torque/current mode control is achieved with a sensing of the voltage generated across a sense resistor in the motor drive circuit. This voltage is routed to the on-chip integrated ADC, after which data processing by the CPU, based on a predefined computational algorithm, results in the regulation of the PWM commutation signal period(s). As discussed earlier, another key feature of the Z8FMC600 MCU is the direct coupling of the on-chip integrated comparator to the PWM module to enable fast, cycle-by-cycle shutdown during an overcurrent fault event. Oscilloscope-generated waveforms representing this sequence of events are shown in Figure. In conjunction with the integrated on-chip hardware blocks, the -phase BLDC motor control software developed for this application allows for ease of programming to achieve the desired closed-loop control characteristics. The routines that enable the sensing of the motor s back-emf and current are all interrupt-driven. It is critical that the highest interrupt priority is assigned to the back-emf sensing event for subsequent synchronization of the commutation events. In this case, Timer 0 is used for the Time Stamp function, as well as for updating the commutation period, if necessary. AN Page 5 of

6 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Figure. Cycle-By-Cycle Shutdown Testing This section describes how to run the code and demonstrate this sensorless brushless motor application including its setup, implementation and configuration, and the results of testing. Equipment Used The following equipment is used to demonstrate the sensorless trapezoidal PWM modulation technique. The first four items are contained in the MultiMotor Development Kit (ZMULTIMC00ZCOG). MultiMotor Development Board (99C58-000G) V AC/DC power supply LINIX -phase VDC, 0 W, 00 RPM BLDC motor (5ZWN-0) Opto-Isolated UART-to-USB adapter (99C59-00G) Z8FMC MultiMotor MCU Module (99C95-00G) Order separately Opto-Isolated USB SmartCable (99C0968) Order separately Digital Oscilloscope AN Page 6 of

7 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Hardware Setup Figure shows the application hardware connections. Figure. The MultiMotor Development Kit with the Z8FMC MCU Module and SmartCable Testing Procedure Observe the following procedure to test -phase sensorless trapezoidal PWM modulation on the Z8FMC600 MCU Module.. Download ZDS II for Z8 Encore! (or newer) from the Zilog Store and install it onto your PC.. Download the AN070-SC0.zip source code file from the Zilog website and unzip it to an appropriate location on your PC.. Connect the hardware as shown in Figure. AN Page 7 of

8 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU a. Verify that the Z8FMC600 MCU Module (99C95) jumpers are configured properly, as follows: J0: Set this jumper to the ON position to activate the V BUS relay on the main board J: Two jumpers are in positions - and 7-8 to allow the UART to function properly J: Three jumpers are in the BEMF_x positions to allow proper sensorless motor control operation b. The cables from the opto-isolated USB SmartCable and the UART-to-USB adapter must be connected to two of the PC s USB ports. c. Download and install the drivers for the SmartCable and the UART-to-USB adapter, if required. For assistance, refer to the MultiMotor Series Development Kit Quick Start Guide (QS009).. Power the MultiMotor Series Development Board using the V DC adapter that is included in the Kit. 5. Using a serial terminal emulation program such as HyperTerminal, TeraTerm, or Real- Term, configure the serial port to N--N. A console screen should appear on the PC which will show the status of the motor and allow changes to the motor s operation. 6. Launch ZDS II for Z8 Encore! and choose Open Project from the File menu. Browse to the directory on your PC into which you downloaded the AN070-SC0 source code. Locate the AN070_SC0.zdsproj file, click to highlight it, and select Open. 7. Ensure that the RUN/STOP switch on the Z8FMC600 MCU Module is in the STOP position. 8. In ZDS II, compile and flash the firmware to the Z8FMC600 MCU Module by selecting Rebuild All from the Build menu. Next, select Debug Download code, followed by Debug Go. 9. Set the RUN/STOP switch on the Z8FMC600 MCU Module to RUN. The motor should begin turning. 0. In the GUI terminal console, enter the letter U to switch to UART control; a menu similar to the example shown in Figure 5 should appear. As a result, commands can be entered using the console to change the motor s operation. AN Page 8 of

9 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Figure 5. GUI Terminal Showing the UART Control. At the Input Command: prompt, enter the letter H to reestablish hardware control; see Figure 6. AN Page 9 of

10 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Figure 6. GUI Terminal Showing Hardware Control You can now add your application software to the main program to experiment with additional functions. Note: While debugging your code, ensure that the opto-isolated USB SmartCable controls the reset pin of the MCU. After debugging and running your code, detach the opto-isolated USB SmartCable from J of the MultiMotor MCU Module to free the Reset pin and apply a power cycle to reset the MCU from Debug Mode. Results This sensorless brushless motor control application was tested with a -phase BLDC motor connected to Zilog s MultiMotor Development Board. Testing of the Z8FMC600 MultiMotor MCU Module confirms a seamless start-up of the motor from an idle mode to full operational speed, plus on-the-fly reversal of the direction of rotation, an extremely fast fault-detection cycle, and a lower total solution cost. The BLDC motor specifications are: AN Page 0 of

11 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Manufacturer: Linix Motor type: -wire, -phase brushless DC motor Voltage rating: V Power rating: 0 W Maximum speed of rotation: 00 RPM Summary References This application note describes the closed-loop control of a sensorless BLDC motor using the advanced on-chip integrated features of the Z8FMC600 MCU. The software algorithm implemented in this application demonstrates how a three-phase BLDC motor is operated with a minimum set of peripherals using the ADC module for BEMF detection and a Phase Lock Loop for PI speed control. With this implementation, the need for an open loop start-up ramp was eliminated without sacrificing smooth motor start. The results of this application confirm why the Z8FMC600 MCU is ideally suited for sensorless brushless motor control applications. The Z8FMC600 MCU s features, along with the powerful ez8 CPU core and some of the best development tools available in the industry, result in less complex board designs and reduced design cycle time. The following documents are associated with the Z8FMC600 Series of Motor Control MCUs; each is available for download on Z8FMC6 Series Motor Control Product Specification (PS06) MultiMotor Series Development Kit Quick Start Guide (QS009) MultiMotor Series Development Kit User Manual (UM06) ez8 CPU Core User Manual (UM08) Zilog Developer Studio II Z8 Encore! User Manual (UM00) BLDC Motor Control Using Sensored Sinusoidal PWM Modulation with the Z8FMC600 MCU Application Note (AN067) Three-Phase Hall Sensor BLDC Driver Using The Z8FMC600 MCU (AN068) Space Vector Modulation of a - Phase AC Induction Motor with the Z8FMC600 MCU Application Note (AN069) AN Page of

12 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Appendix A. Schematic Diagrams Figures 7 and 8 show the schematics for the Z8FMC MCU Module. FAULT0 J J STOP/-RUN DIRECTION PWMH PWML0 PWMH0 XOUT XIN SCK Y VCC_v 0MHZ PWMH PWM0L PWM0h VSS XOUT XIN VDD PA/TXDE/SCK/SCL PWML PWMH PWML PC0 DBG -RESET CPINP 6 PWML PWMH 5 PWML PC0/T0OUT DBG RESET/FAULT0 0 PA7/FAULT/T0OUT/COMPOUT 9 PA/CINP PA/RXD/MISO PA5/TXD/MOSI PA6/CTS/SS/SDA PB7/ANA7 PB6/ANA6 PB5/ANA5 PB/ANA/CINN PB/ANA/OPOUT PA/OPINP/CINN 8 PA0/OPINN 7 6 VREF 5 AVSS AVDD PB0/ANA0/T0IN0 PB/ANA/T0IN PB/ANA/T0IN U Z8FMCxx _LQFP SS- CS+ CS- OPINP OPINN AGND AVCC SENS_A SENS_B SENS_C VREF J VREF SENS_A SENS_B SENS_C TXD_MOSI RXD_MISO J HDR/PIN x6 UART FLASH SELECTION J HDR/PIN x C6 680pF BEMF_A BEMF_B BEMF_C MOSI TXD MISO RXD C5 680pF TXD RXD C 680pF VCC_5VM Vbus_M ENABLE HSA HSB HSC MISO ANA VCC_v HDR/PIN x5 RA U CS VCC 8 A_L PWML0 A_H PWMH0 BEMF_A ANA0 B_H PWMH B_L PWML BEMF_B ANA C_H PWMH C_L PWML BEMF_C ANA CS+ CS- CS ANA5 TEMP VCC_v SO HOLD 7 6 SCK WP SCK 5 MOSI GND SI S5FL0P PLACE J - J6, J8, J9 WHERE THE ROUTING ALLOWS. VCC_v J RXD_MISO TXD_MOSI SS- PB7 ANA6 ANA5 ANA OPOUT PB7 R9 70 D6 RED ON VBUS CTRL MCU J0 R6 0K VCC_v ENABLE PB7 CS+ CS- ANA5 PC0 TEMP CS+ J CS- J5 ANA5 J6 PC0 VCC_v VREF C 0.0uF + OPINP CS+ R7 0K VREF CPINP OPOUT J8 CPINP J9 OPOUT J0 VCC_v R6 R7 0K 0K DBG J INTERFACE IF VCC_v is used remove R8 and install R0 =.K -RESET ANA6 C 0.0uF R0.K R K C7 000pF/nF C R8 0 ohm R 5K 0uF VCC_v CPINP OPOUT OPINN AVCC 00PF C5 R9.K C6 0.uF R 7.87K R 9.9K R5 0K C8 pf CS- VBUS_M ENABLE PWML0 PWMH0 BEMF_A PWMH PWML BEMF_B ANA PWMH PWML BEMF_C HSA HSB HSC HDR/PIN x CKT R/A HOUSING DBG SW BU-000P -RESET/-FAULT C9 0.0uF GND R8 0 ohm C0 0.0uF AGND Figure 7. Z8FMC600 MultiMotor MCU Module, # of AN Page of

13 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU VCC_5V J6 VCC_5VM C0 0.uF VCC_5V C.7uF VCC_v VCC_5VL D PMEG00 U Vin GND Enable 5 Vout NC NCP55SNTG C C.7uF 0.uF, 50V VCC_v R9 0 J7 HDR/PIN x VCC_v D GREEN. OK 00K R R 00K DIRECTION R DIRECTION SW HDR/PIN x J8 00 ohm EG8 VCC_5V STOP/-RUN R5 SW 00 ohm EG8 D5 N8W STOP/-RUN J9 RXD TXD 5 6 x6 RT-ANGL Figure 8. Z8FMC600 MultiMotor MCU Module, # of AN Page of

14 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Figures 9 and 0 show the schematics for the MultiMotor Development Board. VCC_V D VBUS_B C 0.uF A_H A_L BAV9WS U 8 VCC VBOOT 7 IN_HI DRV_HI 6 IN_LO BRIDGE 5 GND DRV_LO NCP506B D7 R. ohm R. ohm R 0 ohm R. ohm GA_H Phase_A GA_L C 0.uF GA_H + C 0uF, 50V R 50K Q IXTY6N055T GB_H R5 50K Q IXTY6N055T GC_H Phase_C R6 50K Q IXTY6N055T BAV9WS Phase_B ENABLE C 0.uF B_H B_L C9 0.uF C_H C_L VCC_5VM Vbus_M ANA ENABLE PE7 HSA PD PD HSC PD5 VCC IN_HI IN_LO GND J VCC U IN_HI HDR/PIN x5 D BAV9WS NCP506B D8 IN_LO GND D BAV9WS U VBOOT DRV_HI BRIDGE DRV_LO NCP506B BAV9WS VBOOT DRV_HI BRIDGE DRV_LO D BAV9WS PC7_PWML0 PC6_PWMH0 PD0_PWMH PD_PWML PD_PWMH PD7_PWML C6 GB_H 0.uF R9. ohm Q Q5 R5 R0 R9 R7 0 ohm. ohm R CS- A_L A_H BEMF_A B_H B_L BEMF_B C_H C_L BEMF_C CS+ CS- CS+ CS- TEMP. ohm. ohm R6. ohm R6 0 ohm. ohm J6 Phase_B GB_L GC_H Phase_C GC_L VCC_v C0 0.uF BEMF_A C0 0.0uF R 50K R9 0K BEMF_B Vbus_M C 0.0uF R8 50K R7 0K R5 50K R0 0K PD BEMF_C J6 SETTINGS: - AC MOTOR - BLDC MOTOR C 0.0uF Phase_A Phase_B Phase_C R6 50K R 0K GA_L Phase_A R 50K J R 0K VCC_v T R7 0K TEMP IXTY6N055T SH shunt HSB Q7 MMBT90 C7 0.uF, 50V R5 R0 R 0K GB_L R 50K R ohm, W R8 00 ohm 0K 0K C 0.uf CS+ IXTY6N055T 6 5 BAS6V D C8 0.uF, 50V GC_L R 50K VCC_v Phase_A Phase_B Phase_C 0K Q6 IXTY6N055T HSC HSB HSA R 0K C 0.uf R C5 0.uF, 50V 5 -POS J 5-POS J J5 POS FOR USE WITH AC MOTOR Figure 9. MultiMotor Development Board, # of AN Page of

15 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU J7 EXTERNAL VBUS UP TO 8VDC POS F SHUNT POSITION - EXTERNAL VBUS - INTERNAL VBUS SH shunt J9 HDR/PIN x FUSE/50V/A FH 50V/5x0 holder VBUS J8 HS J0 J V VDC VCC_V + C 0uF 50V USE HEATSINK U TO-0 P PJ-00A D5 N007 IN GND OUT MIC C 0uF VCC_V C6 0.uF USE HEATSINK U5 IN GND OUT MIC C5 0uF VCC_5VM C7 0.uF J 5V J GND VCC_V J GND D6 BAS6 VBUS 5 RL JSA-V VBUS_B R ENABLE Q8 MMBT90 K Figure 0. MultiMotor Development Board, # of AN Page 5 of

16 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Appendix B. Flowcharts This appendix displays flow charts that diagram the Main Function and the Read and Write APIs. Figure shows the main control loop. Start Peripheral Initialization Enable Interrupts Main Loop (Application Code) Figure. Initialization and Application Code Space The back-emf sensing loop is shown in Figure. t0_intrp (Back EMF ISR every Timer0 time out forms Phase Locked Loop Commutation Update (every other interrupt) Back EMF Sensing and PLL Filter (opposite interrupt from Com Update) Return Figure. Initialization and Application Code Space AN Page 6 of

17 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU A flow chart of the PWM loop is shown in Figure. This PWM loop can also be used for specific application code, such as communications or additional user interfaces. pwm_timer_isr (Main Loop ISR every PWM reload, 50μs) Current Loop, PWM duty cycle control (500μs update) LED Status (50μs update) and Blink (0. sec update) Torque (current command from ADC ms update, filtered) Direction Switch (7.5ms update, filtered) Return Figure. Current Loop and Timed Housekeeping AN Page 7 of

18 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Appendix C. Back-EMF Sensing Phase-Locked Loop The Phase-Locked Loop back-emf algorithm, implemented to provide a smooth start-up of the motor, is shown in Figures and 5. Additional details about the specific formulas in these figures are shown in Table ; a description of these calculations follows. Θrotor + (radians) Back EMF Neutral (volts/radian) Back EMF Divider (unitless) ADC (counts/volt) PI Filter (unitless) Θerror k c speed VΘ R ADC counts + ѕτ (radians) π (volts) R + R (volts) V counts (counts) ѕτ (counts) ƒ clock TimerPrescale Speed_constant Speed_count Frequency to Electrical cycles Commutation Angular Frequency Revolutions per Commutation cycles per Integrator Conversion per cycle cycles Timer cycles (sec) (radians/cycle/sec) (rev/cycle) (unitless) (radians/hertz) ѕ mec ƒ mec ƒ elect ƒ com ƒ timer π h h N (cycles/sec) 6 (cycles/sec) (rev/sec) (rev/sec) (cycles/sec) Figure. Back-EMF Sensing Using the Phase-Locked Loop Algorithm Phase Detector Filter Θ (ѕ) + Θe(ѕ) Kd Ud(s) = KdΘe(ѕ) F(ѕ) Uƒ(s) = Ud(ѕ)F(ѕ) Θ (ѕ) VCO Ko ѕ Figure 5. Proportional Integral (PI) Filter Representation for Back-EMF Sensing AN Page 8 of

19 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Table. Back-EMF Sensing Phase-Locked Loop We begin with the transfer function of the Proportional Integral (PI) Filter in the s-plane: AN Page 9 of

20 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Next, by using the bilinear transform identity: where T = the sampling period, yields the following equation. When multiplying by: the calculations that follow are: where: and: Collecting terms and dividing by z yields the following result: AN Page 0 of

21 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU When writing this computation as a computer program, it takes the form of a recursive filter, with the coefficients A0 and A: where: Y0 = Current output Y = Output at the last sample period R0 = Current ADC sample of back-emf (phase voltage V BUS / ) R = Most recent sample of back-emf from ADC A0 = a0 A = a AN Page of

22 Sensorless Brushless DC Motor Control with the Z8FMC600 MCU Customer Support To share comments, get your technical questions answered, or report issues you may be experiencing with our products, please visit Zilog s Technical Support page at To learn more about this product, find additional documentation, or to discover other facets about Zilog product offerings, please visit the Zilog Knowledge Base at zilog.com/kb or consider participating in the Zilog Forum at This publication is subject to replacement by a later edition. To determine whether a later edition exists, please visit the Zilog website at Warning: DO NOT USE THIS PRODUCT IN LIFE SUPPORT SYSTEMS. LIFE SUPPORT POLICY ZILOG S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF ZILOG CORPORATION. As used herein Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness. Document Disclaimer 05 Zilog, Inc. All rights reserved. Information in this publication concerning the devices, applications, or technology described is intended to suggest possible uses and may be superseded. ZILOG, INC. DOES NOT ASSUME LIABILITY FOR OR PROVIDE A REPRESENTATION OF ACCURACY OF THE INFORMATION, DEVICES, OR TECHNOLOGY DESCRIBED IN THIS DOCUMENT. ZILOG ALSO DOES NOT ASSUME LIABILITY FOR INTELLECTUAL PROPERTY INFRINGEMENT RELATED IN ANY MANNER TO USE OF INFORMATION, DEVICES, OR TECHNOLOGY DESCRIBED HEREIN OR OTHERWISE. The information contained within this document has been verified according to the general principles of electrical and mechanical engineering. Z8, Z8 Encore!, Z8 Encore! XP and ZMOTION are trademarks or registered trademarks of Zilog, Inc. All other product or service names are the property of their respective owners. AN Page of