The Microcontroller Idea Book - Jan Axelson's Lakeview Research

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Chapter 8 Table 8-3. Initialization procedure for LCD modules using HD44780 controller. Power on Wait 15 milliseconds after V+ = 4.5V Function set = 30h Wait 4.1 milliseconds Function set = 30h Wait 100 microseconds Function set = 30h Function set to match display module Display on Display clear Entry mode set set I equal to the instruction and call subroutine 900, which clears RS, writes the instruction to the display, and toggles E. Using the example program as a model, you can experiment with your own messages by adapting the code in lines 400-530. Listing 8-5 is another test program that displays a prompt on the host’s screen and then displays the character you type at the keyboard both on the host’s screen and on the LCD module. To use this program, you must add lines 10 through 380 of Listing 8-4 to initialize the module and variables. The 4-bit Interface The HD44780’s 4-bit data interface can be convenient if you don’t have a lot of port bits to spare. The minimum interface requires just 6 outputs, to D4-D7, RS, and E. The drawback is that the 4-bit interface is slower in operation and more complicated to program. To send an instruction using a 4-bit interface, you send half at a time over D4-D7, along with the appropriate RS and R/W signals. D0-D3 are unused. For example, with an 8-bit interface, writing Z (5Ah) to the display requires the following operations: clear R/W set RS write 5Ah to D0-D7 bring E high, then low 148 The Microcontroller Idea Book
Displays Listing 8-5. Displays key presses on the host computer’s screen and on an LCD module. 1 REM reserve space for 1 string variable, 2 REM 1 character in length 3 STRING 3,1 4 REM You must add lines 10 through 380 of listing 8-4 5 REM to this program 400 Z=0 410 DO 420 INPUT “Press a key: ”,$(0) 430 PRINT $(0) 440 REM reset display after 8 characters 450 IF Z=8 THEN Z=0:RW=0:I=1:GOSUB 900 460 REM keep track of how many characters are displayed 470 Z=Z+1 480 REM display the character matching the key press 490 D=ASC($(0),1):GOSUB 800 500 WHILE 1=1 600 END 790 REM write data to the display 800 XBY(X)=RS+1 810 XBY(X)=RW 820 XBY(A)=D 830 XBY(X)=E+1:XBY(X)=E 840 RETURN 890 REM write an instruction to the display 900 XBY(X)=RS 910 XBY(A)=I 920 XBY(X)=E+1:XBY(X)=E 930 RETURN The Microcontroller Idea Book 149
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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
Page 107 and 108: Inputs and Outputs Listing 6-2. Set
Page 109 and 110: The 82C55 also has CMOS-compatible
Page 111 and 112: Inputs and Outputs Pin Symbol Input
Page 113 and 114: Inputs and Outputs An 8255 Interfac
Page 115 and 116: Inputs and Outputs XBY(0FC03h)=9BH
Page 117 and 118: To set or clear a different bit, de
Page 119 and 120: Switches and Keypads 7 Switches and
Page 121 and 122: Switches and Keypads Figure 7-2. Us
Page 123 and 124: exact value depending on the switch
Page 125 and 126: Switches and Keypads Figure 7-4. Tw
Page 127 and 128: Switches and Keypads Figure 7-6. A
Page 129 and 130: Switches and Keypads Custom Keypads
Page 131 and 132: Switches and Keypads • A single c
Page 133 and 134: Switches and Keypads Listing 7-3. T
Page 135 and 136: Displays 8 Displays In addition to
Page 137 and 138: Displays Figure 8-1. LED interfaces
Page 139 and 140: Displays Figure 8-2. Ways to connec
Page 141 and 142: Displays Figure 8-4. Four output po
Page 143 and 144: Displays Figure 8-5. The ICM7218D c
Page 145 and 146: In Figure 8-5’s circuit, an 82(C)
Page 147 and 148: Displays Figure 8-7. With the TC721
Page 149 and 150: Displays Figure 8-8. With a charact
Page 151 and 152: Table 8-1. LCD modules containing t
Page 153 and 154: Each character in the CG ROM and CG
Page 155 and 156: Displays Interfacing Full control o
Page 157: Displays Listing 8-4 (page 2 0f 2).
Page 161 and 162: Displays Listing 8-6 (page 2 of 2).
Page 163 and 164: Using Sensors to Detect and Measure
Page 165 and 166: • What power supplies are availab
Page 171 and 172: different ground symbols for the tw
Page 173 and 174: 10 REM use single-ended mode 20 REM
Page 181 and 182: Clocks and Calendars 10 Clocks and
Page 183 and 184: Listing 10-1. Uses BASIC-52’s rea
Page 185 and 186: Clocks and Calendars Figure 10-1. P
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
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Wireless Links 12 Wireless Links Wi
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Wireless Links Figure 12-2. This in
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Wireless Links Because there are th
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Wireless Links Figure 12-4. The GP1
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through the LEDs. If you prefer an
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Wireless Links Figure 12-6. Using a
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Wireless Links Figure 12-7. Using a
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Wireless Links IREDs emit energy at
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In the infrared link, the amount of
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Calling Assembly-language Routines
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into memory in the 8052-BASIC syste
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2048h in code memory. This is becau
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Binary value 1100 0101 Hex equivale
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Successful assembly is a good sign,
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statement must match the address in
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• BASIC-52’s ON EX1 instruction
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Running BASIC-52 from External Memo
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14-1 for longer delays between writ
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In Figure 3-1, tie pin 31 of U2 (EA
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Related Products 15 Related Product
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Finally, a compiled BASIC program u
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Related Products Figure 15-3. Blue
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Sources Appendix A Sources This App
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Programming and Interfacing the 805
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Sources Product Vendors The followi
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Sources Electronics 123 17921 Rowla
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Sources Micro Future 40944 Cascado
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Sources Siemens Components 2191 Lau
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Programs for Loading Files Appendix
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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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