The Microcontroller Idea Book - Jan Axelson's Lakeview Research

More documents

Recommendations

Info

Chapter 4 because of its longer write times. The program erases all of the stored programs and any options selected with FPROG1-6 in U8. Adding more NVRAM or EEPROM If you want to add an additional 8K of NV RAM or EEPROM, wire another circuit exactly like Figure 4-3’s, except connect pin 20 of the new NVRAM or EEPROM to A000h (pin 10 of U4) ORed with RESET, so that the chip will be accessed from A000h to BFFFh. Adding EPROM Adding EPROM requires more circuitry than NVRAM or EEPROM, because an EPROM must have a programming voltage at its VPP pin during programming. To use the faster FPROG commands, which follow Intel’s Intelligent programming algorithm, you should also raise the EPROM’s supply voltage (VCC) to +6 volts during programming. Although EPROMs do require additional components, once you have them in the circuit, you can use the 8052-BASIC system as a general-purpose EPROM programmer, as described in Chapter 13. You can store assembly-language programs or any information that you want to save in EPROM, whether it’s for use by the 8052-BASIC system or another project. EPROM Types Since EPROMs were first developed in the 1970’s, each generation of devices has allowed larger capacities, faster programming, and reduced programming voltages. Although the recommended programming algorithms, or procedures, for EPROMs are alike in many ways, the details often vary, depending on the device and manufacturer. Programming Algorithms For critical applications, there is no substitute for consulting the EPROM’s data sheet and following its recommendations exactly. But for general use, you can get reliable results with most EPROMs by using one of the two algorithms supported by BASIC-52. 50-millisecond programming. This algorithm is an older, slower procedure. To program a location in the EPROM, you apply a programming voltage to the VPP input, set the address and data lines to the desired values, and apply a 50-millisecond programming pulse at the PGM input to write the data into the EPROM at the selected address. You then increment the address, apply the new data and programming pulse, and continue in this way until all locations are programmed. After programming, you compare the EPROM’s contents to the programming data to verify that all locations programmed correctly. (BASIC-52 varies from this standard by verifying each location immediately after programming.) 56 The Microcontroller Idea Book
This is the recommended algorithm for older, smaller-capacity EPROMs like the 2-kilobyte 2716 and 4-kilobyte 2732, and some 8-kilobyte 2764s. These typically require a programming voltage of 21 or 25 volts at the EPROM’s VPP input. Intelligent programming. This algorithm uses much shorter programming pulses, and verifies after each attempt. After each 1-millisecond programming pulse, you read the EPROM location to see if the programming succeeded. If not, you try again, up to 25 times. When the location verifies, you apply a final pulse equal to three times the total amount of programming pulses already applied. For example, if it takes five attempts to verify, you would apply a final 15-millisecond pulse. Finally, when all locations are programmed, you verify each once more. For Intelligent programming, VPP is typically +12.5 volts, and VCC, the EPROM’s main power supply, is also raised from +5 to +6V during programming. Intelligent programming is the recommended algorithm for many 8K EPROMs. Intel’s 2764 EPROM uses 21V, 5—millisecond programming, while the 2764A uses 12.5V, Intelligent programming. Quick-pulse programming. Some CMOS 8K EPROMs (27C64) can use an even faster programming algorithm called Quick-Pulse. In Quick-Pulse programming, VPP is typically 12.75V, VCC is 6.25, and the programming pulses are 100 microseconds. BASIC-52 doesn’t offer Quick-Pulse programming as an option. Choosing an algorithm. As a rule, you can program an EPROM using a slower algorithm than the recommended one, so you should be able to program any 12.5V EPROM with 50-millisecond programming, with VPP at 12.5V and VCC at +5V. And, any EPROM that can use Quick-Pulse programming should also program with the Intelligent or 50-millisecond programming algorithm and voltages. But whatever you do, don’t exceed the recommended programming voltages for the device at VCC and VPP. EPROM Pinouts Figure 4-4 shows the pinout for a 2764 8K EPROM. Once again, the pin functions and locations are similar to those in an 8K RAM. During normal operation, the data pins (DQ0-DQ7) are read-only. Pin 27, which is Write Enable (WE) on RAM, is PGM, or program pulse, on the EPROM, and pin 1, which has no connection on RAM, is VPP, or programming voltage, on the EPROM. EPROM-programming Circuits Saving Programs Figure 4-5 shows additions to Figure 4-3’s circuits that enable you to program a 12.5V 8K EPROM instead of NVRAM or EEPROM. Table 4-2 is a parts list for Figure 4-5’s circuits. The Microcontroller Idea Book 57
Page 1 and 2:
The Microcontroller Idea Book Circu
Page 3 and 4:
Table of Contents Chapter 1 Microco
Page 5 and 6:
Chapter 11 Control Circuits 185 Swi
Page 7 and 8:
Introduction Introduction This book
Page 9 and 10:
A chapter on assembly-language inte
Page 11 and 12:
Microcontroller Basics 1 Microcontr
Page 13 and 14:
But along with cheap, powerful, and
Page 15 and 16: makes sense. For simpler designs, a
Page 17 and 18: Microcontroller Basics Several tech
Page 19 and 20: Interpreters and compilers are two
Page 21 and 22: Inside the 8052-BASIC 2 Inside the
Page 23 and 24: Inside the 8052-BASIC • You can a
Page 25 and 26: hardware manuals. For programming,
Page 27 and 28: Inside the 8052-BASIC Figure 2-2 Pi
Page 29 and 30: Inside the 8052-BASIC Table 2-2. (p
Page 31 and 32: Inside the 8052-BASIC Code and data
Page 33 and 34: Powering Up 3 Powering Up This chap
Page 35 and 36: Powering Up Table 3-1. Parts list f
Page 37 and 38: Powering Up Figure 3-2. Truth table
Page 39 and 40: Powering Up Jumper J3 chooses the c
Page 41 and 42: Powering Up Figure 3-3. This is the
Page 43 and 44: Powering Up Construction Tips These
Page 45 and 46: Powering Up Serial Connectors Conne
Page 47 and 48: You’re now ready to power up the
Page 49 and 50: Powering Up PRINT XTAL Line Editing
Page 51 and 52: Powering Up PORT 1 Bit Values: Bit
Page 53 and 54: Powering Up Listing 3-3. Allows use
Page 55 and 56: 10 CLOCK 1:TIME=0:SEC=0 20 A=0 30 P
Page 57 and 58: Saving Programs 4 Saving Programs I
Page 59 and 60: guaranteed for at least ten years.
Page 61 and 62: Saving Programs Figure 4-3. Circuit
Page 63 and 64: Jumper J4 is optional. It enables y
Page 65: memory on bootup. This is what allo
Page 69 and 70: Saving Programs Figure 4-5. Additio
Page 71 and 72: problems with EPROMs that have a 10
Page 73 and 74: supply. The chip requires an additi
Page 75 and 76: Programming 5 Programming When you
Page 77 and 78: Subroutines have two advantages. Fi
Page 79 and 80: Programming • Hexadecimal numbers
Page 81 and 82: Programming It can be hard to find
Page 83 and 84: Programming Math Operators = + - *
Page 85 and 86: Programming expression / expression
Page 87 and 88: Programming DO: [program statements
Page 89 and 90: Programming LOG(expression) Returns
Page 91 and 92: Programming PH0.@ Same as PRINT@, b
Page 93 and 94: Programming RCAP2 Retrieves or assi
Page 95 and 96: Programming PRINT TAB(2) “hello
Page 97 and 98: Inputs and Outputs 6 Inputs and Out
Page 99 and 100: 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 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 167 and 168:
Page 169 and 170:
Page 171 and 172:
different ground symbols for the tw
Page 173 and 174:
10 REM use single-ended mode 20 REM
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
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
Page 205 and 206:
Page 207 and 208:
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 and 236:
Successful assembly is a good sign,
Page 237 and 238:
statement must match the address in
Page 239 and 240:
Page 241 and 242:
Page 243 and 244:
• BASIC-52’s ON EX1 instruction
Page 245 and 246:
Page 247 and 248:
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:
Page 279 and 280:
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
Page 287 and 288:
Index S sample and hold, 169 SBC, 3
show all

The Microcontroller Idea Book - Jan Axelson's Lakeview Research

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?