The Microcontroller Idea Book - Jan Axelson's Lakeview Research

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Chapter 10 Figure 10-2. Wiring diagram for the DS1286 Watchdog Timekeeper in an 8052-BASIC system. accessing the watchdog register. When IPSW (register B, bit 6) is 1, the time-of-day interrupt is on INTA, and the watchdog interrupt is on INTB. When IPSW is 0, these are reversed, with the watchog on INTA and the time-of-day on INTB. The chip also has a 1024-Hz square-wave output. Table 10-1 details the functions of the DS1286’s registers, which store time, date, configuration, and status information. To initialize the clock/calendar, you write the current time and date into registers 0-2, 4, 6, and 8 through A, then start the clock by clearing EOSC (bit 7 of register 9). Time and date values are stored in binary-coded decimal (BCD) format. In BCD, a 4-bit nibble represents one decade, and nibbles greater than 9 (1001) are not allowed. Table 10-2 shows numbers expressed in decimal, BCD, and binary. Some values in the DS1286 don’t require a full 8 bits. For example, since the month can go no higher than 12, you need only 5 bits to store its value. 176 The Microcontroller Idea Book
Clocks and Calendars Table 10-1. Register functions for the DS1286 Watchdog Timekeeper Register Function Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 0 Clock 0.1 seconds 0.01 seconds 1 0 10 seconds seconds 2 0 10 minutes minutes 3 Alarm MASK 10 minutes alarm minutes alarm 4 Clock 0 12/24 10hr or 10hr hours AM/PM 5 Alarm MASK 12/24 10hr or 10hr hour alarm AM/PM 6 Calendar 0 0 0 0 0 days 7 Alarm MASK 0 0 0 0 day alarm 8 Calendar, 0 0 10 date date 9 Oscillator EOSC ESQW 0 10 mo months A 10 years years B Command TE IPSW IBH/LO PU/LVL WAM TDM WAF TDF C Watchdog 0.1 seconds 0.01 seconds D 10 seconds seconds E-3F User free for any use Time of Day Alarm Mask Bits Minutes Hours Day Alarm Frequency 1 1 1 Once per minute 0 1 1 When minutes match 0 0 1 When hours and minutes match 0 0 0 When hours, minutes, and days match Symbol Function Symbol Function EOSC Enable Oscillator PU/LVL Pulse/Level Triggered Interrupts ESQW Enable Square Wave Out WAM Watchdog Alarm Mask TE Transfer Enable TDM Time-of-day Mask IPSW Interrupt Switch WAF Watchdog Alarm Flag IBH/LO Interrupt B High/Low Trigger TDF Time-of-day Flag The Microcontroller Idea Book 177
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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
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 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: Clocks and Calendars Figure 10-1. P
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
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Page 235 and 236: Successful assembly is a good sign,
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statement must match the address in
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Calling Assembly-language Routines
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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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