The Microcontroller Idea Book - Jan Axelson's Lakeview Research

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Chapter 13 EPROM programmer, for storing assembly-language routines or anything else you want to program into an EPROM, for use on an 8052-BASIC system or another device. Assembly-language Basics The bare 8052 chip understands just one language: the binary machine codes that make up the chip’s instruction set. The 8052’s data book describes the function of each of the machine codes. You can, of course, write programs without having to look up binary codes, by using a programming language. The language that is closest to the machine codes is assembly language, where a mnemonic, or abbreviation, represents each of the codes. The assembly-language program that you write is called a source file. After you write a source file, you must use an assembler to translate the source file into an object file, which contains the machine codes that the chip will execute. You also must have a way of storing the object file in the 8052-BASIC system’s memory, where the 8052-BASIC chip can access it. The BASIC-52 interpreter is itself an assembled program that the 8052 runs on boot-up. The interpreter reads your BASIC-52 programs from memory and translates them into machine codes for the 8052 to execute. It does the same for the BASIC-52 commands that you type at the keyboard. The interpreter program includes many modular routines that BASIC-52 uses, such as reading a character from the serial port or comparing two values. BASIC-52 programs are slow for two reasons. One is that the interpreter must translate each line of code every time it executes it. With assembly language, the assembler translates the program only once, and the 8052 then reads and executes the binary codes directly from memory. The other reason for the slowness of BASIC-52 programs is that the nterpreter program’s translation from BASIC-52 to machine code doesn’t result in the most efficient code. Programming directly in assembly language gives you much greater control over the final code that the 8052 will execute. Incidentally, assembly language isn’t the only way to get faster execution times. Other options include using a BASIC or C compiler or using a faster crystal to clock the 8052. But as a rule, these approaches will not speed up programs as dramatically as assembly language. What You Need To add assembly-language routines to your BASIC-52 programs, you need several items: a programming reference with details about the 8052’s assembly language, a text editor for writing the source files, an assembler to create the executable files, memory in the 8052-BASIC system for storing your programs, and a way to transfer your executable files 218 The Microcontroller Idea Book
into memory in the 8052-BASIC system. The following sections describe each of these in more detail. Programming Reference This book concentrates on BASIC-52 programming. I’ve included enough information about assembly language to get you started programming, plus what you need to know to interface assembly-language routines to BASIC-52. But there is much more to assemblylanguage programming than I can cover here. If you are an experienced assembly-language programmer, Intel’s Embedded Microcontrollers handbook, or a similar reference from another 8052 vendor, may be all you need as a reference. The handbook includes a programmer’s guide and describes each of the 8052’s instructions. If you’re just starting out with assembly language, you might want to invest in a more complete text that includes examples and explanations of how to put together a program. Examples can be extremely useful for seeing how to do common tasks like generating a timing delay or handling an interrupt. Appendix A lists several books on the 8051 family that include programming examples and tutorials. Text Editor Calling Assembly-language Routines The text editor is the software that you use to create your source files. The editor program must be able to create files in straight ASCII format, without adding any formatting codes. Just about all word processors have this ability, as do simpler text editors like MS- DOS’s EDIT. Assembler The assembler is the program that creates an object, or executable, file from your source file. If you write assembly-language programs for your personal computer, you use an assembler, such as MASM for 80x86 microprocessors. MASM creates files that will execute on 80x86 systems, using the 80x86’s instruction set. To assemble a program for an 8052 microcontroller, you need a special type of assembler called a cross assembler. The cross assembler runs on your personal, or host, computer, but creates programs to run on a different chip, such as the 8052. Assemblers for 8051-family chips, which you can use for 8052 programming, are widely available. Appendix A lists vendors of assemblers and BBS’s from which you can download free and shareware assemblers. The Microcontroller Idea Book 219
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The Microcontroller Idea Book Circu
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Table of Contents Chapter 1 Microco
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Chapter 11 Control Circuits 185 Swi
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Introduction Introduction This book
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A chapter on assembly-language inte
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Microcontroller Basics 1 Microcontr
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But along with cheap, powerful, and
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makes sense. For simpler designs, a
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Microcontroller Basics Several tech
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Interpreters and compilers are two
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Inside the 8052-BASIC 2 Inside the
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Inside the 8052-BASIC • You can a
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hardware manuals. For programming,
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Inside the 8052-BASIC Figure 2-2 Pi
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Inside the 8052-BASIC Table 2-2. (p
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Inside the 8052-BASIC Code and data
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Powering Up 3 Powering Up This chap
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Powering Up Table 3-1. Parts list f
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Powering Up Figure 3-2. Truth table
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Powering Up Jumper J3 chooses the c
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Powering Up Figure 3-3. This is the
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Powering Up Construction Tips These
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Powering Up Serial Connectors Conne
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You’re now ready to power up the
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Powering Up PRINT XTAL Line Editing
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Powering Up PORT 1 Bit Values: Bit
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Powering Up Listing 3-3. Allows use
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10 CLOCK 1:TIME=0:SEC=0 20 A=0 30 P
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Saving Programs 4 Saving Programs I
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guaranteed for at least ten years.
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Saving Programs Figure 4-3. Circuit
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Jumper J4 is optional. It enables y
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memory on bootup. This is what allo
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This is the recommended algorithm f
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Saving Programs Figure 4-5. Additio
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problems with EPROMs that have a 10
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supply. The chip requires an additi
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Programming 5 Programming When you
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Subroutines have two advantages. Fi
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Programming • Hexadecimal numbers
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Programming It can be hard to find
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Programming Math Operators = + - *
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Programming expression / expression
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Programming DO: [program statements
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Programming LOG(expression) Returns
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Programming PH0.@ Same as PRINT@, b
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Programming RCAP2 Retrieves or assi
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Programming PRINT TAB(2) “hello
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Inputs and Outputs 6 Inputs and Out
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Unassigned space remains in the mem
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U11 is a 74HCT138 3-to-8-line decod
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If you wish, you can wire U14’s i
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Inputs and Outputs Figure 6-4. Outp
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Inputs and Outputs Listing 6-2. Set
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The 82C55 also has CMOS-compatible
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Inputs and Outputs Pin Symbol Input
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Inputs and Outputs An 8255 Interfac
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Inputs and Outputs XBY(0FC03h)=9BH
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To set or clear a different bit, de
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Switches and Keypads 7 Switches and
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Switches and Keypads Figure 7-2. Us
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exact value depending on the switch
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Switches and Keypads Figure 7-4. Tw
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Switches and Keypads Figure 7-6. A
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Switches and Keypads Custom Keypads
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Switches and Keypads • A single c
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Switches and Keypads Listing 7-3. T
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Displays 8 Displays In addition to
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Displays Figure 8-1. LED interfaces
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Displays Figure 8-2. Ways to connec
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Displays Figure 8-4. Four output po
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Displays Figure 8-5. The ICM7218D c
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In Figure 8-5’s circuit, an 82(C)
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Displays Figure 8-7. With the TC721
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Displays Figure 8-8. With a charact
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Table 8-1. LCD modules containing t
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Each character in the CG ROM and CG
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Displays Interfacing Full control o
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Displays Listing 8-4 (page 2 0f 2).
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Displays Listing 8-5. Displays key
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Displays Listing 8-6 (page 2 of 2).
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Using Sensors to Detect and Measure
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• What power supplies are availab
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different ground symbols for the tw
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10 REM use single-ended mode 20 REM
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Page 177 and 178: Using Sensors to Detect and Measure
Page 179 and 180: Using Sensors to Detect and Measure
Page 181 and 182: Clocks and Calendars 10 Clocks and
Page 183 and 184: Listing 10-1. Uses BASIC-52’s rea
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Page 187 and 188: Clocks and Calendars Table 10-1. Re
Page 189 and 190: If you want an alarm frequency othe
Page 191 and 192: Clocks and Calendars Listing 10-3 (
Page 193 and 194: Clocks and Calendars Listing 10-3 (
Page 195 and 196: Control Circuits 11 Control Circuit
Page 197 and 198: the LSTTL part, and wire the desire
Page 199 and 200: Control Circuits Listing 11-1. Cont
Page 201 and 202: Control Circuits Listing 11-2. Demo
Page 203 and 204: Control Circuits disables the outpu
Page 209 and 210: Wireless Links 12 Wireless Links Wi
Page 211 and 212: Wireless Links Figure 12-2. This in
Page 213 and 214: Wireless Links Because there are th
Page 215 and 216: Wireless Links Figure 12-4. The GP1
Page 217 and 218: through the LEDs. If you prefer an
Page 219 and 220: Wireless Links Figure 12-6. Using a
Page 221 and 222: Wireless Links Figure 12-7. Using a
Page 223 and 224: Wireless Links IREDs emit energy at
Page 225 and 226: In the infrared link, the amount of
Page 227: Calling Assembly-language Routines
Page 231 and 232: 2048h in code memory. This is becau
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Page 235 and 236: Successful assembly is a good sign,
Page 237 and 238: statement must match the address in
Page 239 and 240: Calling Assembly-language Routines
Page 243 and 244: • BASIC-52’s ON EX1 instruction
Page 249 and 250: Running BASIC-52 from External Memo
Page 251 and 252: 14-1 for longer delays between writ
Page 253 and 254: In Figure 3-1, tie pin 31 of U2 (EA
Page 255 and 256: Related Products 15 Related Product
Page 257 and 258: Finally, a compiled BASIC program u
Page 259 and 260: Related Products Figure 15-3. Blue
Page 261 and 262: Sources Appendix A Sources This App
Page 263 and 264: Programming and Interfacing the 805
Page 265 and 266: Sources Product Vendors The followi
Page 267 and 268: Sources Electronics 123 17921 Rowla
Page 269 and 270: Sources Micro Future 40944 Cascado
Page 271 and 272: Sources Siemens Components 2191 Lau
Page 273 and 274: Programs for Loading Files Appendix
Page 275 and 276: Programs for Loading Files Listing
Page 277 and 278: Programs for Loading Files Listing
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Programs for Loading Files Listing
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Number Systems Appendix C Number Sy
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Number Systems This table shows the
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Index Index A ADC, 158 - 169 addres
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Index S sample and hold, 169 SBC, 3
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The Microcontroller Idea Book - Jan Axelson's Lakeview Research

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