MSP430 Family Mixed-Signal Microcontroller Application Reports

Transcription

1 MSP430 Family Mixed-Signal Microcontroller Application Reports Author: Lutz Bierl Literature Number: SLAA024 January 2000 Printed on Recycled Paper

2 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI s standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements. CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE ( CRITICAL APPLICATIONS ). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER S RISK. In order to minimize risks associated with the customer s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI s publication of information regarding any third party s products or services does not constitute TI s approval, warranty or endorsement thereof. Copyright 2000, Texas Instruments Incorporated

3 Preface Read This First How to Use This Manual This document contains the following chapters: Chapter 1 MSP430 Microcontroller Family: Introduction to the MSP430 family, advantages of the MSP430 concept, and operating modes Chapter 2 MSP Bit Analog-To-Digital Converter: Chapter 3 MSP430 Hardware Applications: Chapter 4 MSP430 Application Examples: Chapter 5 Software Applications: Chapter 6 On-Chip Peripherals: Chapter 7 Hints and Recommendations: Chapter 8 Architecture and Instruction Set: Chapter 9 CPU Registers: Read This First iii

4 Contents Contents 1 MSP430 Microcontroller Family Introduction Related Documents Notation MSP430 Family MSP430C31x MSP430C32x MSP430C33x Advantages of the MSP430 Concept RISC Architecture Without RISC Disadvantages Real-Time Capability With Ultra-Low Power Consumption Digitally Controlled Oscillator Stability Stack Processing Capability MSP430 Application Operating Modes Active Mode Low Power Mode 3 (LPM3) Low Power Mode 4 (LPM4) Analog-To-Digital Converters Architecture and Function of the MSP Bit ADC A table of contents for this application report is found starting on page Application Basics for the MSP Bit ADC A table of contents for this application report is found starting on page Additive Improvement of the MSP Bit ADC Characteristic A table of contents for this application report is found starting on page Linear Improvement of the MSP Bit ADC Characteristic A table of contents for this application report is found starting on page Nonlinear Improvement of the MSP Bit ADC Characteristic A table of contents for this application report is found starting on page Using the MSP430 Universal Timer/Port Module as an Analog-to-Digital Converter A table of contents for this application report is found starting on page v

5 Contents 3 Hardware Applications I/O Port Usage General Usage Zero Crossing Detection Output Buffering Universal Timer/Port I/Os I/O Used for Fast Serial Transfers Storage of Calibration Constants External EPROM for Calibration Constants Internal RAM for Calibration Constants M-Bus Connection I2C Bus Connection Hardware Optimization Use of Unused Analog Inputs Use of Unused Segment Lines for Digital Outputs Digital-to-Analog Converters R/2R Method Weighted Resistors Method Digital-to-Analog Converters Connected Via the I2C Bus PWM DAC With the Universal Timer/Port Module PWM DAC With the Timer_A Connection of Large External Memories Power Supplies for MSP430 Systems Battery-Power Systems Accumulator-Driven Systems AC-Driven Systems Supply From Other System DC Voltages Supply From the M Bus Supply Via a Fiber-Optic Cable Application Examples Electricity Meters Overview The Measurement Principle The Analog-to-Digital Converter of the MSP430C32x Analog Interfaces to the MSP Single-Phase Electricity Meters Dual-Phase Electricity Meters Three-Phase Electricity Meters Measurement of Voltage, Current, Apparent Power, and Reactive Power Calculation of the System Current Consumption System Components Electricity Meter With an External ADC Error Simulation for an MSP430C32x-Based Electricity Meter vi

6 Contents 4.2 Gas Meter Water Flow Meter Heat Allocation Counter Heat Volume Counter Battery Charge Meter Connection of Sensors Sensor Connection and Linearization Connection of Special Sensors RF Readout MSP430 Electricity Meter MSP430 Electricity Meter With Front End MSP430 Ferraris-Wheel Electricity Meter With RF Readout RF-Interface Module Protocol RF Readout With Other Metering Applications Ultra-Low-Power Design With the MSP430 Family The Ultra Low Power Concept of the MSP Current Consumption and Battery Life Minimization of the System Consumption Correct Termination of Unused Terminals (3xx Family) Other MSP430 Applications Controller for a Heating Installation Pocket Scale Remote Control Applications Sub-Controller for a TV Set Sub-Controller of a Personal Computer Subcontroller of a FAX Device Digital Motor Control Introduction Digital Motor Control With Pulse Width Modulation (PWM) Digital Motor Control With TRIACs Motor Measurements Conclusion Software Applications Integer Calculation Subroutines Unsigned Multiplication 16 x 16-Bits Signed Multiplication 16 x 16-Bits Unsigned Multiplication 8 x 8-Bits Signed Multiplication 8 x 8-Bits Unsigned Division 32/16-Bits Signed Division 32/16-Bits Shift Routines Square Root Routines Contents vii

7 Contents Signed and Unsigned 32-Bit Compares Random Number Generation Rules for the Integer Subroutines Table Processing Two Dimensional Tables Three-Dimensional Tables Signal Averaging and Noise Cancellation Oversampling Continuous Averaging Weighted Summation Wave Digital Filtering Rejection of Extremes Synchronization of the Measurement to Hum Real-Time Applications Active Mode Normal Mode is Low-Power Mode 3 (LPM3) Normal Mode is Low-Power Mode 4 (LPM4) Recommendations for Real-Time Applications General Purpose Subroutines Initialization RAM clearing Routine Binary to BCD Conversion BCD to Binary Keyboard Scan Temperature Calculations for Sensors Data Security Applications Status/Input Matrix The Floating-Point Package General Common Conventions The Basic Arithmetic Operations Calling Conventions for the Comparison Internal Data Representation Execution Cycles Conversion Routines Memory Requirements of the Floating Point Package Inclusion of the Floating-Point Package into the Customer Software Software Examples Battery Check and Power Fail Detection Battery Check Power Fail Detection Conclusion On-Chip Peripherals The Basic Timer viii

8 Contents Change of the Basic Timer Frequency Elimination of Crystal Tolerance Error Clock Subroutines The Basic Timer Used as a 16-Bit Timer The Watchdog Timer Supervision of One Task With the Watchdog Supervision of Multiple Tasks With the Watchdog The Timer_A Introduction Timer_A Hardware Timer Modes The Timer_A Interrupt Logic The Output Units Limitations of the Timer_A Miscellaneous Software Examples for the Continuous Mode Software Examples for the Up Mode Software Examples for the Up/Down Mode The Hardware Multiplier Function of the Hardware Multiplier Multiplication Modes Programming the Hardware Multiplier Software Applications The System Clock Generator Initialization Entering of Low Power Mode Wake-Up From Interrupts in Low Power Mode Adaptation of the DCO Tap during Calculations Wake-Up from Interrupts in Low Power Mode Change of the System Frequency The Modulation Bit M Use Without Crystal High System Frequencies Together With the 14-bit ADC Dependencies of the System Clock Generator Short Time Accuracy of the System Clock Generator The Oscillator Fault Interrupt Flag Conclusion The RESET Function Description of the MSP430 RESET Function RESET With the Internal Hardware, Including the Watchdog Reliable RESET With Slowly Rising Power Supplies Conclusion The Universal Timer/Port Module Universal Timer/Port Used as an Analog-to-Digital Converter Contents ix

9 Contents Universal Timer/Port Used as a Timer The Crystal Buffer Output The USART Module Introduction Baud Rate Generation Software Routines The 8-Bit Interval Timer/Counter Introduction Function of the UART Hardware The Baud Rate Generation and Correction Software Routines The Comparator_A Definitions Used With the Application Examples Fast Comparator Input Check Voltage Measurement Hints and Recommendations Hints and Recommendations Design Checklist Most Frequent Software Errors Most Frequent Hardware Errors Checklist for Problems Hardware Related Problems Software Related Problems Run Time Estimation Architecture and Instruction Set Introduction Reasons for the Popularity of the MSP Orthogonality Addressing Modes RISC Architecture Without RISC Disadvantages Constant Generator Status Bits Stack Processing Usability of the Jumps Byte and Word Processor High Register Count Emulation of Non-Implemented Instructions No Paging Effects and Advantages of the MSP430 Architecture Less Program Space Shorter Programs Reduced Development Time x

10 Contents Effective Code Without Compressing Optimum C Code The MSP430 Instruction Set Implemented Instructions Emulated Instructions Benefits High Processing Speed Small CPU Area High ROM Efficiency Easy Software Development Usability on into the Future Flexibility of the Architecture Usable for Modern Programming Techniques Conclusion CPU Registers CPU Registers The Program Counter PC Stack Processing Byte and Word Handling Constant Generator Addressing Program Flow Control Special Coding Techniques Conditional Assembly Position Independent Code Reentrant Code Recursive Code Flag Replacement by Status Usage Argument Transfer With Subroutine Calls Interrupt Vectors in RAM Instruction Execution Cycles Double Operand Instructions Single Operand Instructions Jump Instructions Interrupt Timing Contents xi

11 Figures Figures 1 1 MSP430C31x Block Diagram MSP430C32x Block Diagram MSP430C33x Block Diagram MSP430 Input for Zero-Crossing Timing for the Zero Crossing Output Buffering The I/O Section of the Universal Timer/Port Module Connections for Fast Serial Transfer External EPROM Connections TSS721 Connections to the MSP I2C Bus Connections Unused ADC Inputs Used as Outputs R/2R Method for Digital-to-Analog Conversion Weighted Resistors Method for Digital-to-Analog Conversion I2C-Bus for Digital-to-Analog Converter Connection PWM for the DAC PWM Timing by the Universal Timer/Port Module and Basic Timer PWM for DAC PWM Timing by Universal Timer/Port Module and Basic Timer PWM Generation With Continuous Mode PWM Generation With Up Mode PWM Generation With Up-Down Mode External Memory Control With MSP430 Ports External Memory Control With Shift Registers EEPROM Control With Direct Addressing by I/O Ports Addressing of 1-MB RAM With the MSP430C33x Addressing of 1-MB RAM With the MSP430C31x Battery-Power MSP430C32x System Battery-Power MSP430C31x System Accumulator-Driven MSP430 System With Battery Management Voltages and Timing for the Half-Wave Rectification Half-Wave Rectification With 1 Voltage and a Zener Diode Half-Wave Rectification With One Voltage and a Voltage Regulator Half-Wave Rectification With Two Voltages and Two Voltage Regulators Voltages and Timing for Full-Wave Rectification Full Wave Rectification for one Voltage With a Voltage Regulator xii

12 Figures 3 34 Full-Wave Rectification for Two Voltages With Voltage Regulators Simple Capacitor Power Supply for a Single Voltage Capacitor Power Supply for a Single Voltage Split Capacitor Power Supply for Two Voltages Split Capacitor Power Supply for Two Voltages With Discrete Components Simple Power Supply from Other DC Voltages Power Supply from other DC Voltages With a Voltage Regulator Supply from the M Bus Supply via Fiber-Optic Cable Two Measurement Methods for Electronic Electricity Meters Timing for the Reduced Scan Principle (Single Phase) Reduced Scan Measurement Principle Allocation of the ADC Range Explanation of ADC Deviation (2nd Column of Table 4 5) Use of the Actual ADC Characteristic for Corrections (8 Subranges Used) MSP Bit ADC Grounding Split Power Supply for Level Shifting Virtual Ground IC for Level Shifting Resistor Interface Without Current Source Resistor Interface With Current Source Current Measurement Current Measurement With a Ferrite Core Voltage Measurement Single-Phase Electricity Meter With Shunt Resistor Single-Phase Electricity Meter With Current Transformer and RF Readout Timing for the Reduced Scan Principle (Dual-Phase Meter) Dual-Phase Electricity Meter With Current Transformers and Virtual Ground Dual-Phase Electricity Meter With Current Transformers and Software.... Offset Normal Timing for the Reduced Scan Principle (Three-Phase Meters) Evenly Spaced Timing for the Reduced Scan Principle (Three-Phase Meters) Three-Phase Electricity Meter With Ferrite Cores and Software Offset Electricity Meter With Current Transformers and Split Power Supply Timing for the Reduced Scan Principle Electricity Meter With an External 16-Bit ADC Allocation of the ADC Range Explanation of the ADC Deviation Gas Meter With MSP430C32x Gas Meter With MSP430C31x MSP430C336 Gas Meter Electronic Water Flow Meter Electronic Heat Allocation Meter With MSP430C32x Electronic Heat Allocation Meter With MSP430C31x Heat Volume Counter MSP430C32x Contents xiii

13 Figures 4 35 Heat Volume Counter With 4-Wire-Circuitry MSP430C32x Heat Volume Counter With 16 Bits Resolution MSP430C32x Battery Charge Meter MSP430C32x Resistive Sensors Connected to MSP430C32x Measurement With Reference Resistors Connection of Bridge Assemblies Simplified ADC Characteristic Fixing of Bridge Assemblies Into One ADC Range Gas Sensor Connection to the MSP430C32x Connection of Digital Sensors (Thermometer) Connection of Sensors With Frequency Output Respective Time Output Revolution Counter With a Digital Hall Sensor Measurement of the Magnetic Flux With an Analog Hall Sensor MSP430C32x EE Meter With RF Readout MSP430 EE Meter With RF Readout MSP430 With a Ferraris-Wheel Meter and RF Readout RF-Interface Module RF-Modulation Modes M-BUS Long Frame Format Sequence of Data Transmission Conventional Solution for a Battery-Driven System Solution With MSP430 for a Battery-Driven System Approximated Characteristics for the Low Power-Supply Currents Current Consumption Characteristic Connection of Keys to Inputs Turnoff of External Circuits Intelligent Heating Installation Control With the MSP Heating Installation Controller for a Single-Family Home Simple Battery Driven Scale Remote Control Transmitter for Security Applications Remote Control Transmitter for Audio/Video Remote Control Receiver With the MSP MSP430 in a TV Set MSP430 in an AC-Powered Personal Computer MSP430 in a Battery-Powered Personal Computer With Battery Management MSP430-Controlled FAX Device Block Diagram of the UTPM (16-Bit Timer Mode) Low-Frequency PWM-Timing Generated With the Universal Timer/Port Module Low Frequency PWM Timing by Universal Timer/Port Module and Basic Timer Transistor Output Stage Allowing Both Directions of Rotation Control for Two MOSFET Output Stages PWM Motor Control With a MOSFET H-Bridge PWM Motor Control for Brushless DC Motor Integrated PWM Motor Control With Static Rotation Direction xiv

14 Figures 4 79 Integrated PWM Motor Control With Dynamic Rotation Direction PWM Motors Control for High Motor Voltages PWM Outputs for Different Phase Voltages PWM Motors Control for High Motor Voltages Minimum System and Maximum System Using the MSP430 Family TRIAC Control for AC Motors and DC Motors Positive and Negative TRIAC Gate Control Static and Dynamic TRIAC Gate Control Nonregulated Voltage for the TRIAC Control Minimum System and Maximum System With the MSP430 Family Overcurrent Detection With Single and Multiple Thresholds Motor Voltage Measurement and Current Measurement Support Functions for the TRIAC Control Change of the Direction of Rotation for a Universal Motor x 16 Bit Multiplication Register Use x 8 Bit Multiplication Register use Unsigned Division Register Use Signed Division Register Use Data Arrangement in Tables Two-dimensional Function Algorithm for Two-Dimensional Tables Table Configuration for Signed X and Y Algorithm for a Three-Dimensional Table Frequency Response of the Continuous Averaging Filter Reduction of Hum by Synchronizing to the AC Frequency. Single Measurement Reduction of Hum by Synchronizing to the AC Frequency. Differential Measurement Keyboard Connection to MSP Connection of Different Input Signals Nonlinear Function K = f(n) DES Encryption Subroutine Biphase Space Code Matrix for Few Valid Combinations Stack Allocation for.float and.double Formats Floating Point Formats for the MSP430 FPP Signed Binary Input Buffer Format 16 Bits Unsigned Binary Input Buffer Format 16 Bits Signed Binary Input Buffer Format 32 Bits Unsigned Binary Input Buffer Format 32 Bits Binary Number Format 48 Bit Binary Number Format 48 Bit BCD Buffer Format Binary Number Format Function f(x) Contents xv

15 Figures 5 30 Complex Number on TOS and in Memory (.FLOAT Format) Connection of the Voltage Reference Battery Check With an External Comparator Discharge Curves for the Battery Check With the Universal Timer/Port Module Battery Check With the Universal Timer/Port Module Power Fail Detection by Observation of the Charge Capacitor Voltages for the Power-Fail Detection by Observation of the Charge Capacitor Power-Fail Detection by Observation of the Charge Capacitor Power-Fail Detection With the Watchdog Voltages for the Power-Fail Detection With the Watchdog Power-Fail Detection With a Supply Voltage Supervisor Voltages for the Power-Fail Detection With a Supply Supervisor Crystal Calibration Crystal Frequency Deviation With Temperature The Hardware of the 16-Bit Timer_A (Simplified MSP430x33x Configuration) The Timer Register Block Timer Control Register (TACTL) Timer Vector Register (TAIV) Simplified Logic of the Timer Interrupt Vector Register Capture/Compare BLock The Capture/Compare Registers CCRx Function of the Capture/Compare Registers (CCRx) Timer Control Registers (CCTLx) Two Different Timings Generated With the Continuous Mode Three Different Asymmetric PWM Timings Generated With the Up Mode Two Different Symmetric PWM Timings Generated With the Up/Down Mode Unsafe Output Mode Changes Simplified Logic of the Output Units Connection of the Port3 Terminals to the Timer_A (MSP430C33x Configuration) PWM Generation in the Continuous Mode (CCR1 only controls TA1) PWM Generation in the Continuous Mode (CCR0 and CCR1 control TA1) PWM Signals at TAx in the Up Mode (CCR0 contains 4) PWM Signals at Pin TAx With the Up/Down Mode (CCR0 contains 3) Five independent Timings Generated in the Continuous Mode DTMF Filters and Mixer TRIAC Control With Timer_A Static and Dynamic TRIAC Gate Control Mixture of Capture Mode and Compare Mode With the Continuous Mode Compare Mode With Timer Values greater than 16 Bit (shown for CCR1) Capture Mode With Timer Values greater than 16 Bit (shown for CCR3) Five Different Timings Extending the Normal Timer_A Range MSP430 Operation Without Crystal RF Interface Module Connection to the MSP xvi

16 Figures 6 32 RF Modulation Modes Amplitude Modulation Biphase Code Modulation Biphase Space Modulation Real Time Clock Application of the Timer_A Three Different Asymmetric PWM-Timings Generated With the Up Mode Digital-to-Analog Conversion TRIAC Control With Timer_A Signals for the TRIAC Gate Control With Up Mode RF Modulation Modes Capture Mode With the Up Mode (shown for CCR1) PWM Generation and Capturing With the Up Mode PWM Signals at Pin TAx for the Current MSP430C33x Version PWM Signals at Terminal TAx for the Improved MSP430C11x Version PWM Outputs for Different Phase Voltages PWM Motors Control for High Motor Voltages Symmetric PWM Timings Generated With the Up/Down Mode TRIAC Control and 3-Phase Control With the Timer_A Signals for the TRIAC Gate Control With Up/Down Mode Biphase Code Modulation With the Up/Down Mode Capturing With the Up/Down Mode Capture Mode With the Up/Down Mode (Capture/Compare Block 3) PWM Generation and Capturing With the Up/Down Mode Block Diagram of the MSP y 16-Bit Hardware Multiplier The Internal Connection of the MSP Bit Hardware Multiplier y 40-Bit Unsigned Multiplication MPYU y 32-Bit Signed Multiplication MPYS Finite Impulse Response Filter Storage for the Finite Impulse Response Filter RAM and ROM Allocation for the Fast Fourier Transformation Algorithm Control of the DCO by the System Clock Frequency Integrator Switching of The DCO Taps Dependent on NDCOmod Simplified MSP430 RESET Circuitry Generation of RESET-Signals for External Peripherals Battery-Powered System With RESET Switch Simple RESET Circuit With a PNP Transistor RESET Circuit With a Comparator and a Reference Diode RESET Circuit With a Schmitt Trigger and a Reference Diode RESET Generation With a Comparator Power Fail Detection With a Supply Voltage Supervisor System Voltages With a Power Supply Supervisor Power Supply From Other DC Voltages With a Voltage Regulator/Supervisor Block Diagram of the Universal Timer/Port Module Block Diagram of the Universal Timer/Port Module (16-Bit Timer Mode) Contents xvii

17 Figures 6 76 Low Frequency PWM Timing Generated With the Universal Timer/Port Module Two MSP430s Running From the Same Crystal The Crystal Buffer Output Used for a DC/DC Converter The MSP430 Family USART Hardware The USART Switched to the UART Mode The RS232 Format (Levels at the MSP430) The RS232 Format (Levels on the Transmission Line) USART Control Registers Used for the UART Mode The Baud Rate Generator Baud Rate Correction Function MSP430 8-Bit Interval Timer/Counter Module Hardware RS232 Format (Levels at the MSP430) The RS232 Format (Levels on the Transmission Line) UART Hardware Registers The 8-Bit Timer/Counter Transmit Mode Interrupt Timing for the Transmit Mode The 8-Bit Timer/Counter in Receive Mode Interrupt Timing for the Receive Mode Baud Rate Correction Transmitted Data Format Received Data Format Comparator_A Hardware Fast Comparator Input Check Circuitry Voltage Measurement Orthogonal Architecture (Double Operand Instructions) Non-Orthogonal Architecture (Dual Operand Instructions) Addressing Modes Word and Byte Addresses of the MSP Register Set of the MSP Word and Byte Configuration Argument Allocation on the Stack Argument and Result Allocation on the Stack Execution Cycles for Double Operand Instructions Execution Cycles for Single Operand Instructions xviii