The Microcontroller Idea Book - Jan Axelson's Lakeview Research

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Chapter 8 Table 8-2. Instruction summary for the HD 44780 LCD controller. Instruction RS R/W D7 D6 D5 D4 D3 D2 D1 D0 Function Execution time (max) Display clear 0 0 0 0 0 0 0 0 0 1 Clear display. Reset display from shift. Set DD RAM=0 1.64 msec Display/cursor home Entry mode set 0 0 0 0 0 0 0 0 1 X Shift=0. DD RAM=0 0 0 0 0 0 0 0 1 I/D S I/D: increment (1) , decrement (0) cursor or display shift after data transfer. S: shift on (1) , off (0). 1.64 msec 40 μsec Display on/off 0 0 0 0 0 0 1 D C B D: display on (1) , off (0). C: cursor on (1) , off (0). B: cursor blink on (1) , off(0). 40 μsec Display/cursor shift 0 0 0 0 0 1 S/C R/L X X S/C: shift display (1), cursor (0). R/L: shift right (1), left (0). 40 μsec Function set 0 0 0 0 1 DL N 0 X X DL: 8-bit (1), 4-bit (0) interface. N: dual (1), single (1) line display. 40 μsec CG RAM address set DD RAM address set Busy flag/address counter read CG/DD RAM data write CG/DD RAM data read 0 0 0 1 CG5 CG4 CG3 CG2 CG1 CG0 Load address counter with CG0-CG5. Subsequent data goes to CG RAM. 0 0 1 DD6 DD5 DD4 DD3 DD2 DD1 DD0 Load address counter with DD0-DD6. Subsequent data goes to DD RAM. 0 1 BF AC6 AC5 AC4 AC3 AC2 AC1 AC0 Read busy flag (BF) and address counter (AC0- AC6) 1 0 D7 D6 D5 D4 D3 D2 D1 D0 Write data (D0-D7) to CG RAM or DD RAM. 1 1 D7 D6 D5 D4 D3 D2 D1 D0 Place data from CG RAM or DD RAM on D0- D7. 40 μsec 40 μsec 0 40 μsec 40 μsec X=don’t care 142 The Microcontroller Idea Book
Each character in the CG ROM and CG RAM has an 8-bit address, or character code. Conveniently, the codes for the upper and lower-case Roman alphabet and common punctuation are same as the ASCII codes for those characters (21h through 7Dh). For example, the pattern for A is stored at address 41h, B is stored at at 42h, and so on. An 8-bit instruction register (IR) stores instruction codes and addresses, and an 8-bit data register (DR) stores character codes. When you read or write to the chip, you must select the appropriate register. The DD RAM stores up to eighty 8-bit character codes. Each character position on the display corresponds to an address in the DD RAM, and the character codes stored in the DD RAM determine what is displayed at each position. On power up, on a 2-line display, the leftmost position on the top line has an address of 0, with the rest of the positions in the line addressed in sequence. The second line begins at 40h, even if the top line has fewer than 40h positions. The instructions allow you to configure a module so that the DD RAM’s address increments each time a character is written to the display. This way, the characters automatically appear in sequence on the display without your having to specify an address each time. Because the second line begins at 40h, however, the display will not wrap around automatically to this line. For example, on a 2-line, 16-position display, line 1 ends at 0Fh and line 2 begins at 40h. To move from the rightmost position of line 1 to the leftmost position of line 2, you have to change the address counter to 40h. In addition, some displays with a single physical line of characters have two logical lines. In a 16-character display of this type, the first 8 characters are addressed from 0 to 7, and the second 8 are addressed from 40h to 47h. With this type of display, you must set the address counter to 40h before you write to the second half of the line. On a small display where all 80 bytes of DD RAM aren’t needed, you can use the spare DD RAM as general-purpose RAM. Reading and Writing Writing to the LCD module involves the following steps: Bring RS high to write data, or low to write an instruction. Bring R/W low. Bring D0-D7 to their desired states. Wait at least 140 nanoseconds. Bring E high for at least 450 nanoseconds. Bring E low. Displays The Microcontroller Idea Book 143
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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
Page 101 and 102: U11 is a 74HCT138 3-to-8-line decod
Page 103 and 104: If you wish, you can wire U14’s i
Page 105 and 106: 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: Table 8-1. LCD modules containing t
Page 155 and 156: Displays Interfacing Full control o
Page 157 and 158: Displays Listing 8-4 (page 2 0f 2).
Page 159 and 160: Displays Listing 8-5. Displays key
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
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Control Circuits disables the outpu
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Control Circuits Listing 11-4. Cont
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Control Circuits Listing 11-5. Cont
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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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