ST ST7 Series User manual

ST7
8-BIT MCU FAMILY
USER GUIDE
JANUARY 1999
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USE IN LIFE SUPPORT DEVICES OR SYSTEMS MUST BE EXPRESSLY AUTHORIZED.
STMicroelectronicsPRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN
LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF
STMicroelectronics. As used herein:
1. Life support devices or systems are those
which (a) are intended for surgical implant into
the body, or (b) support or sustain life, and
whosefailure toperform, when properly used in
accordance with instructions for use provided
with the product, can be reasonably expected
to result in significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to
perform can reasonably be expected to cause
the failure of the life support device or system,
or to affect its safety or effectiveness.
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1INTRODUCTION........................................................12
1.1 WHOISTHISBOOKWRITTENFOR? .................................12
1.2 ABOUTTHEAUTHORS.............................................12
1.3 HOWISTHISBOOKORGANIZED? ...................................12
1.4 WHYAMICROCONTROLLER?.......................................13
1.4.1 Electroniccircuitry......................................................15
1.4.2 Choiceofmicrocontrollermodel ...........................................17
1.4.3 Choiceofdevelopmenttools .............................................17
2HOWDOESATYPICALMICROCONTROLLERWORK? .......................19
2.1 THE CENTRAL PROCESSING UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.2 HOW THE CPU AND ITS PERIPHERALS MAKE UP A SYSTEM . . . . . . . . . . . . 21
2.2.1 CPU ................................................................21
2.2.2 Memory..............................................................21
2.2.3 Input-Outputs . . . ......................................................23
2.2.4 InterruptController .....................................................24
2.2.5 Bus .................................................................25
2.2.6 ClockGenerator .......................................................25
2.2.7 ResetGenerator .......................................................25
2.3 CORE ...........................................................25
2.3.1 ArithmeticandLogicUnit(ALU) ...........................................25
2.3.2 Program Counter ......................................................26
2.3.3 InstructionDecoder.....................................................26
2.3.4 StackPointer .........................................................26
2.4 PERIPHERALS ....................................................27
2.4.1 Parallel Input-Outputs ...................................................27
2.4.2 AnalogtoDigitalConverter...............................................28
2.4.3 ProgrammableTimer ...................................................28
2.4.4 SerialPeripheralInterface ...............................................28
2.4.5 Watchdog Timer . ......................................................28
2.5 THEINTERRUPTMECHANISMANDHOWTOUSEIT ....................29
2.5.1 Interrupthandling ......................................................29
2.5.1.1 Hardware mechanism . .............................................31
2.5.1.2 Hardwaresourcesofinterrupt ........................................31
2.5.1.3 Global interrupt enable bit ...........................................32
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2.5.1.4 Softwareinterruptinstruction.........................................32
2.5.1.5 Savingthestateoftheinterruptedprogram .............................32
2.5.1.6 Interruptvectorization ..............................................32
2.5.1.7 Interruptserviceroutine.............................................34
2.5.1.8 InterruptReturninstruction ..........................................34
2.5.2 Softwareprecautionsrelatedtointerruptserviceroutines .......................34
2.5.2.1 SavingtheYregister ...............................................34
2.5.2.2 Managing the stack . . . .............................................35
2.5.2.3 Resetting the hardware interrupt request flags ...........................35
2.5.2.4 Makinganinterruptserviceroutineinterruptible ..........................35
2.5.2.5 Datadesynchronizationandatomicity..................................36
2.5.3 Conclusion: the benefits of interrupts . . . ....................................38
2.6 AN APPLICATION USING INTERRUPTS: A MULTITASKING KERNEL . . . . . . . 39
2.6.1 Pre-emptivemultitasking ................................................39
2.6.2 Cooperative multitasking . . . .............................................41
2.6.3 Multitaskingkernels ....................................................42
2.6.3.1 Advantagesofprogrammingwithamultitaskingkernel ....................42
2.6.3.2 Thetaskdeclarationandallocation....................................42
2.6.3.3 Tasksleepingandwaking-up ........................................42
2.6.3.4 Multitasking kernel overhead .........................................43
3PROGRAMMINGAMICROCONTROLLER...................................45
3.1 ASSEMBLY LANGUAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
3.1.1 When to use assembly language ..........................................45
3.1.2 Development process in assembly language .................................46
3.1.2.1 Assembly language . . . .............................................47
3.1.2.2 Assembler .......................................................48
3.1.2.3 Linker...........................................................49
3.1.2.4 Theprojectbuilder/makeutility .......................................51
3.1.2.5 EPROMburners ..................................................52
3.1.2.6 Simulators .......................................................53
3.1.2.7 In-circuitemulators ................................................54
3.2 CLANGUAGE.....................................................55
3.2.1 WhyuseC? ..........................................................55
3.2.2 Tools used with C language . .............................................57
3.2.3 Debugging in C . . ......................................................58
3.3 DEVELOPMENT CHAIN SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
3.4 APPLICATIONBUILDERS...........................................61
3.5 FUZZY-LOGICCOMPILERS .........................................61
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4ARCHITECTUREOFTHEST7CORE.......................................62
4.1 POSITIONOFTHEST7WITHINTHESTMCUFAMILY....................62
4.2 ST7CORE........................................................63
4.2.1 Addressingspace......................................................65
4.2.2 Internalregisters.......................................................65
4.2.2.1 Accumulator(A)...................................................65
4.2.2.2 Condition Code register (CC) ........................................65
4.2.2.3 Index registers (X and Y) ............................................67
4.2.2.4 Program Counter (PC) . .............................................68
4.2.2.5 StackPointer(SP).................................................68
4.3 INSTRUCTION SET AND ADDRESSING MODES . . . . . . . . . . . . . . . . . . . . . . . . 70
4.3.1 A word about mnemonic language .........................................70
4.3.2 Addressingmodes .....................................................72
4.3.3 Instructionset .........................................................73
4.3.4 Coding of the instructions and the address ..................................74
4.3.4.1 Prefixbyte .......................................................74
4.3.4.2 Opcodebyte .....................................................75
4.3.4.3 The addressing modes in detail . . . ....................................77
4.4 ADVANTAGES OF THE ST7 INSTRUCTION SET AND ADDRESSING MODES 82
5PERIPHERALS.........................................................84
5.1 CLOCKGENERATOR ..............................................84
5.1.1 ST72251 Miscellaneous Register ..........................................84
5.1.2 ST72311 Miscellaneous Register ..........................................85
5.2 INTERRUPT PROCESSING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
5.2.1 Interruptsourcesandinterruptvectors......................................86
5.2.1.1 InterruptssourcesfortheST72251....................................87
5.2.1.2 InterruptsourcesfortheST72311.....................................88
5.2.2 Interruptvectorization ...................................................89
5.2.3 Globalinterruptenablebit................................................90
5.2.4 TRAPinstruction.......................................................91
5.2.5 Interrupt mechanism ....................................................91
5.2.5.1 Savingtheinterruptedprogramstate ..................................91
5.2.5.2 Interruptserviceroutine.............................................91
5.2.5.3 Restoringtheinterruptedprogramstate:TheIRETinstruction ...............92
5.2.6 Nestingtheinterruptservices.............................................92
5.3 PARALLELINPUT-OUTPUTPORTS ..................................94
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5.3.1 ST72251 I/O Ports .....................................................94
5.3.2 ST72311 I/O Ports .....................................................96
5.4 WATCHDOG TIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
5.4.1 Aim of the watchdog ....................................................99
5.4.2 Watchdog Description ..................................................100
5.4.3 Using the Watchdog to protect an application ...............................103
5.5 16-BITTIMER ....................................................103
5.5.1 Timerclock ..........................................................104
5.5.2 Free running counter ..................................................105
5.5.2.1 Reading the free running counter . ...................................105
5.5.2.2 Resetting the free running counter ...................................106
5.5.2.3 TheTOFflag ....................................................107
5.5.3 Input capture operation .................................................108
5.5.4 Output compare operation . . ............................................110
5.5.5 One-pulsemode......................................................113
5.5.6 Pulse-Width Modulation mode ...........................................115
5.6 ANALOGTODIGITALCONVERTER .................................117
5.6.1 Description ..........................................................117
5.6.2 UsingtheAnalogtoDigitalConverter......................................118
5.6.3 Theproblemoftheconverter'saccuracy ...................................119
5.6.4 Using the ADC to convert positive and negative voltages; increasing its resolution . .120
5.6.4.1 Measuring negative and positive voltages ..............................120
5.6.4.2 Increasingtheresolution ...........................................121
5.6.4.3 ApplicationExamples .............................................124
5.7 SERIALPERIPHERALINTERFACE ..................................125
5.8 SERIALCOMMUNICATIONINTERFACE ..............................128
5.8.1 Bit rate generator .....................................................128
5.8.2 Send and receive mechanism ...........................................129
5.8.3 Statusregister........................................................132
5.8.4 ControlRegister2.....................................................132
5.8.5 Using the Wake-Up feature in a multiprocessor system ........................133
5.8.6 Handling the interrupts .................................................133
6STMICROELECTRONICSPROGRAMMINGTOOLS ..........................135
6.1 ASSEMBLER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .135
6.1.1 Anoverviewoftheassemblerfunction.....................................135
6.1.2 Instructioncoding .....................................................137
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6.1.3 Declaringvariables....................................................138
6.1.4 Declaringconstants ...................................................140
6.1.4.1 Constantdata ...................................................140
6.1.4.2 Symboldefinition .................................................141
6.1.5 Relocation commands .................................................142
6.1.5.1 Whatisrelocation? ...............................................142
6.1.5.2 Segmentdefinition................................................143
6.1.5.3 UsingtheSegmentdirectiveinthesourcefile...........................145
6.1.5.4 Segmentallocation ...............................................146
6.1.5.5 Initializationofvariablesatpower-on..................................148
6.1.5.6 Referencing symbols and labels between modules .......................151
6.1.6 Conditional assembly ..................................................154
6.1.7 Macros .............................................................156
6.1.7.1 Replaceableparameters ...........................................157
6.1.7.2 Localsymbols ...................................................158
6.1.7.3 Conditional statements in macros . ...................................160
6.1.8 Some miscellaneous features ............................................162
6.1.8.1 EQUandCEQUpseudo-ops........................................162
6.1.8.2 #DEFINE pseudo-op . . ............................................162
6.1.8.3 Numberingsyntaxdirectives ........................................163
6.1.9 Objectandlistingfiles..................................................163
6.1.9.1 Objectfiles......................................................164
6.1.9.2 Listingfiles......................................................164
6.2 LINKERANDASCII-HEXCONVERTER ...............................165
6.2.1 Thelinkingprocess....................................................165
6.2.2 Hexfiletranslator .....................................................167
6.2.3 The back-annotation pass of the assembler .................................168
6.3 INSTALLINGWINEDITANDTHESOFTWARETOOLS...................168
6.3.1 WinEdittexteditor.....................................................168
6.3.1.1 InstallingWinEdit .................................................168
6.3.1.2 ConfiguringWinEdit...............................................169
6.3.2 InstallingtheSTMicroelectronicsSoftwareTools.............................169
6.4 BUILDINGADEMONSTRATIONPROGRAM ...........................170
6.4.1 Purposeofthedemonstrationprogram ....................................170
6.4.2 Inventoryoftheprogramfiles............................................170
6.4.3 Descriptionoftheprogramfiles ..........................................171
6.4.3.1 The PROJECT.WPJ file ..........................................171
6.4.3.2 The main source file, MAIN.ASM and the timer source file, TIMER500.ASM . . .
173 6.4.3.3 The REG72251.ASM file and the REGISTER.INC file .................176
6.4.3.4 The MAP72251.ASM file .........................................178
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6.4.3.5 The CATERPIL.BAT file ..........................................179
6.4.4 Using WinEdit to change and compile the files ...............................180
7DEBUGGERANDPROMPROGRAMMERTUTORIALFORST72251 ............183
7.1 STMICROELECTRONICS HARDWARE TOOLS . . . . . . . . . . . . . . . . . . . . . . . . .183
7.1.1 EPROMProgrammingBoards ...........................................183
7.1.2 StarterKits ..........................................................184
7.1.3 DevelopmentKits .....................................................184
7.1.4 Emulators ...........................................................184
7.2 EPROMPROGRAMMERBOARDS ...................................184
7.2.1 EPROMprogrammerInstallation .........................................185
7.2.2 UsingtheEPROMERsoftware...........................................185
7.3 EMULATORANDDEBUGGER ......................................189
7.3.1 Introducing the emulator and the debugger .................................189
7.3.2 Installing the emulator and the debugger ...................................189
7.3.3 Using the debugger ...................................................193
7.3.3.1 Loading the application ............................................193
7.3.3.2 Running the application ............................................195
7.3.3.3 Watchingtheregistersandvariables..................................195
7.3.3.4 UsingInspectandWatch...........................................197
7.3.3.5 Usingbreakpoints ................................................199
7.3.3.6 Watchingthecontentsofthestack ...................................200
7.3.3.7 Watchingtheexecutiontrace .......................................201
7.3.3.8 Morefeaturestocomelater.........................................202
7.4 PURPOSEOFTHETUTORIAL ......................................202
7.5 SCHEMATICDRAWINGOFTHEPRINTEDCIRCUITBOARD .............204
7.6 DEVELOPING THE PROGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .204
7.6.1 Peripherals used to implement the solution .................................204
7.6.2 Thealgorithmofeachtask ..............................................205
7.6.3 AsimplemultitaskingkernelfortheST7 ...................................206
7.6.3.1 StartTasks routine ...............................................206
7.6.3.2 The Yield routine.................................................208
7.6.4 Thesourcecodeoftheapplication........................................211
7.6.4.1 Main file (Multitsk.asm) ...........................................212
7.6.4.2 ADC source file(Acana.asm) .......................................216
7.6.4.3 Kernel source file (Littlk.asm)..................................217
7.7 RUNNING THE APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .219
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7.8 SUMMARY REMARKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .219
8CLANGUAGEANDTHECCOMPILER ....................................221
8.1 CLANGUAGEEXTENSIONSFORMICROCONTROLLERS ...............221
8.2 DESCRIPTION AND INSTALLATION OF THE HICROSS TOOL CHAIN . . . . . .222
8.3 USINGTHECCOMPILER ..........................................226
8.3.1 Memoryallocation.....................................................226
8.3.1.1 Read-only constants . . ............................................227
8.3.1.2 EEPROMnon-volatilestorage.......................................228
8.3.1.3 PageZerovariables...............................................229
8.3.1.4 Far and near pointers . ............................................229
8.3.2 Initializationofvariablesandconstantvariables..............................230
8.3.3 Inputs and outputs ....................................................230
8.3.3.1 First method: using macros .........................................231
8.3.3.2 Second method: defining variables ...................................231
8.3.4 Interrupthandling .....................................................232
8.3.5 Limitations put on the full implementation of C language .......................232
8.4 USING THE ASSEMBLER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .233
8.4.1 UsingIn-lineassemblerstatementswithinaCsourcetext .....................233
8.4.1.1 Single-statementassemblerblock....................................233
8.4.1.2 Multiple-statementassemblerblock ..................................234
8.4.2 UsingtheHiwareassembler.............................................235
8.5 USINGTHELINKER...............................................235
8.6 USING THE EPROM BURNER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .237
8.7 PROJECTDIRECTORYSTRUCTURE ................................239
8.7.1 Configdirectory.......................................................239
8.7.2 Objectdirectory.......................................................241
8.7.3 Sourcesdirectory .....................................................241
8.8 HINTSONCWRITINGSTYLEFORTHEST7 ..........................242
8.8.1 Accessingindividualbitsinregisters ......................................242
8.8.2 Settingconfigurationregisters ...........................................245
8.8.3 Usingmacrostodefineexternaldevices ...................................245
8.8.4 Optimizingresourceusage..............................................246
8.8.4.1 Define a function when a group of statements is repeated several times ......247
8.8.4.2 Useshiftsinsteadofmultiplicationanddivision..........................247
8.8.4.3 Limitthesizeofvariablestotheveryminimum..........................248

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8.9 CONCLUSION....................................................248
9 A CARRIER-CURRENT SYSTEM FOR DOMESTIC REMOTE CONTROL . . . . . . . . . 249
9.1 CARRIER CURRENT CONTROL AND THE X-10 STANDARD . . . . . . . . . . . . . 250
9.2 TRANSMITTER...................................................255
9.2.1 Instructionsforuse ....................................................255
9.2.2 Descriptionoftheelectroniccircuit........................................255
9.2.3 Descriptionofthesoftware..............................................259
9.2.3.1 Themainprogram ................................................259
9.2.3.2 TimerACaptureinterruptserviceroutine ..............................262
9.2.3.3 TheTimerBoverflowinterruptserviceroutine ..........................269
9.3 RECEIVER ......................................................272
9.3.1 Instructionsforuse ....................................................272
9.3.2 Electroniccircuitry.....................................................272
9.3.3 Software ............................................................276
9.3.3.1 Interruptfunctions ................................................276
9.3.3.2 Mainprogram....................................................279
9.4 CONCLUSION....................................................285
10SECONDAPPLICATION:ASAILINGCOMPUTER ..........................286
10.1THEORYOFTHECOMPUTATION ...................................288
10.2INTERFACINGTHEMEASUREMENTDEVICES ........................291
10.2.1 Frequency-type devices: speedometer and wind gauge .......................291
10.2.1.1 Interfacing the speedometer ........................................291
10.2.1.2 Interfacing the wind gauge ..........................................291
10.2.1.3 Using a common timer for both speed measurement devices ...............292
10.2.2Interfacingtheweathervane ............................................293
10.3INTERFACINGTHEDISPLAY .......................................294
10.3.1Displaycircuit ........................................................295
10.3.2Push-buttoncircuit ....................................................298
10.3.3LEDcircuit ..........................................................299
10.4INTERFACINGTHEOPTIONALPERSONALCOMPUTER ................299
10.5PROGRAMARCHITECTURE........................................300
10.5.1 Reading and conversion of the speeds . ...................................300
10.5.2Refreshingofthedisplay ...............................................302