The Microcontroller Idea Book - Jan Axelson's Lakeview Research

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Chapter 13 10 CALL 3000h 20 END If necessary, change the address in line 10 to match the value in your routine’s org directive. Each time you run the program, you should see pin 1 on the 8052 change from high to low or low to high. The routine should then return you to the BASIC-52 prompt. If the program crashes and does not return you to BASIC-52, you need to re-examine your listing file to see what went wrong. Remember that the address in BASIC-52’s CALL Figure 13-2. By writing the appropriate values to an output port, you can cause a sine wave to appear at VOUT. 226 The Microcontroller Idea Book
statement must match the address in your file’s org directive. A missing ret instruction in the routine will also cause the system to crash. Example: Creating a Sine Wave When you have the simple routine working, you’re ready to move on to bigger things. For the sine-wave project, we’ll begin by generating a sine wave entirely with BASIC-52 statements. This way, we can first test the added circuits as well as the algorithm, or sequence of steps, that we plan to use to generate the sine wave. It also illustrates the speed limits of BASIC-52. The Circuits Calling Assembly-language Routines Figure 13-2 shows the circuit that interfaces to the 8052. I adapted the circuit from an example in National Semiconductor’s data sheet for the DAC0832. U1 is a DAC0832 digital-to-analog converter, or DAC, which converts data inputs D0-D7 into an analog voltage. D0-D7 are controlled by an output port at E400h. You may change this address to match any output port on your system. Listing 13-4. Sine-wave generator for Figure 13-2’s circuit. 10 REM Begins by calculating and storing sine values 20 REM for 256 locations along a sine wave. 30 REM Line 100 converts a position in the sine wave 40 REM (0-255) to the radians required by the sine 50 REM operator: (0.0246 = 2*PI/256). Adding 1 to the 60 REM sines makes all values positive, from 0 to +2. 70 REM Multiplying by 127.5 results in values that 80 REM range from 0 to 255. 90 FOR I=0 TO 255 100 XBY(3000H+I)=INT((SIN(I*.0246)+1)*127.5+.5) 110 NEXT I 120 PRINT “Sine values are stored in RAM (3000h-30FFh)” 130 PRINT “Press Control+C to quit” 140 REM Write the values in sequence to E400h 150 DO 160 FOR I=3000H TO 30FFH 170 XBY(0E400H)=XBY(I) 180 NEXT I 190 WHILE 1=1 200 END The Microcontroller Idea Book 227
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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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Clocks and Calendars 10 Clocks and
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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 and 228: Calling Assembly-language Routines
Page 229 and 230: into memory in the 8052-BASIC syste
Page 231 and 232: 2048h in code memory. This is becau
Page 233 and 234: Binary value 1100 0101 Hex equivale
Page 235: Successful assembly is a good sign,
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 281 and 282: Number Systems Appendix C Number Sy
Page 283 and 284: Number Systems This table shows the
Page 285 and 286: Index Index A ADC, 158 - 169 addres
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Index S sample and hold, 169 SBC, 3
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