AN0704 interfacing microchip’s MCP3201 analogdigital (AD) converter to MC68HC11E9 based microcontroller

AN704 Interfacing Microchip’s MCP3201 Analog/Digital (A/D) Converter to MC68HC11E9-Based Microcontroller Author: Richard L Fischer Microchip Technology Inc INTRODUCTION Many of the embedded control systems designed today require some flavor of Analog-to-Digital (A/D) Converter Embedded system applications such as Data Acquisition, Sensor Monitoring, and Instrumentation and Control all have varying A/D Converter requirements For the most part, these A/D Converter requirements are a combination of performance, cost, package size basis and availability In some applications a microcontroller with an on-chip A/D Converter may meet the design requirements Typically, these on-chip A/D Converter modules fit well into embedded applications which require a 10-35ksps A/D Converter In other applications, a stand-alone A/D Converter is required for various performance reasons For those applications which require higher performance or remote sense capability, the Microchip MCP3201 12-bit A/D Converter fits very nicely The Microchip Technology Inc MCP3201 employs a classic SAR architecture The device uses an internal sample and hold capacitor to store the analog input while the conversion is taking place Conversion rates of 100ksps are possible on the MCP3201 Minimum clock speed (10 kHz or 625sps, assuming 16 clocks) is a function of the capacitors used for the sample and hold The MCP3201 has a single pseudo-differential input The (IN–) input is limited to ±100mV This can be used to cancel small noise signals present on both the (IN+) and (IN–) inputs This provides a means of rejecting noise when the (IN–) input is used to sense a remote signal ground The (IN+) input can range from the (IN-) input to VREF The reference voltage for the MCP3201 is applied to VREF pin VREF determines the analog input voltage range and the LSB size, i.e.: As the reference input is reduced, the LSB size is reduced accordingly Communication with the MCP3201 is accomplished using a standard SPI™ compatible serial interface This interface allows direct connection to the serial ports of microcontrollers and digital signal processors The MCP3201 is suitable for use with a wide variety of microcontrollers from Microchip and others This application note describes how to interface the MCP3201 with a Motorola MC684C11 microcontroller Application Note, AN702 covers microcontrollers based on the Intel 8051 architecture Figure shows the hardware schematic for this interface Appendix A contains a listing of the source code CIRCUIT DESCRIPTION The serial interface of the Microchip MCP3201 A/D Converter has three wires, a serial clock input (DCLK), the serial data output (DOUT) and the chip select input signal (CS/SHDN) For this simple circuit interface, the Motorola MC68HC11E9 SPI port is used PORTD: is configured for the serial clock and PORTD: is the data input to the microcontroller The SPI clock rate for this application is set at MHz The MC68HC11 is configured in the master mode with its CPOL and CPHA bits set to logic one (default setting on power-up) A conversion is initiated with the high to low transition of CS/SHDN (active low) The chip select is generated by PORTD: of the microcontroller The device will sample the analog input from the rising edge of the first clock after CS goes low for 1.5 clock cycles On the falling edge of the second clock, the device will output a low null bit With the next 12 clocks, the MCP3201 will output the result of the conversion with the MSB first (See Figure and Figure 3) Data is always output from the device on the falling edge of the clock If the device continues to receive clocks while CS/SHDN is low, the device will output the conversion LSB first If more clocks are provided to the device while CS/SHDN is still low (after the LSB first data has been transmitted), the device will clock out zeros indefinitely LSB size = VREF 212 SPI is a trademark of Motorola Inc  1999 Microchip Technology Inc DS00704B-page AN704 FIGURE 1: Hardware Schematic DS00704B-page  1999 Microchip Technology Inc AN704 CS/SHDN MCU latches data from A/D Converter on rising edges of DCLK DCLK 10 11 12 13 14 15 16 Data is clocked out of A/D Converter on falling edges DOUT NULL BIT B11 B10 HI-Z B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 HI-Z B1 LSB first data begins to come out MCU Received Data (After 16 clocks) FIGURE 2: ? ? B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 B1 SPI Communication using 8-bit segments (Mode 1,1: SCLK idles high) CS/SHDN MCU latches data from A/D Converter on rising edges of DCLK DCLK 10 11 12 13 14 15 16 Data is clocked out of A/D Converter on falling edges DOUT HI-Z NULL B11 B10 B9 BIT B8 B6 B7 B5 B4 B3 B2 B1 B0 B1 B2 HI-Z LSB first data begins to come out MCU Received Data (After 16 clocks) FIGURE 3: ? ? B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 B1 SPI Communication using 8-bit segments (Mode 0,0: SCLK idles low)  1999 Microchip Technology Inc DS00704B-page AN704 As the analog input signal is applied to the IN+ and INinputs, it is ratioed to the VREF input for conversion scaling Digital output code = VIN x F.S VREF Where: VIN = analog input voltage V(IN+) - V(IN–) VREF = reference voltage F.S = full scale = 4096 VREF can be sourced directly from VDD or can be supplied by an external reference In either configuration, the VREF source must be evaluated for noise contributions during the conversion The voltage reference input of the MCP3201 ranges from 250mV to 5VDC, which approximately translates to a corresponding LSB size from 61µV to 1.22mV per bit 1.22mV = 5VDC 212 bits For this simple application, the MCP3201 voltage reference input is tied to 5VDC This translates to a 1.22mV/bit resolution for the A/D Converter module The voltage input to the MCP3201 is implemented with a multi-turn potentiometer The output voltage range of this passive driver is approximately 0VDC to 5VDC Finally, a simple RS-232 interface is implemented using the USART peripheral of the microcontroller and a MAX233 transceiver IC The USART transmits the captured A/D Converter binary value, both in ASCII and Decimal, to the PC terminal at 9600 baud As with all applications which require moderate to high performance A/D Converter operation, proper grounding and layout techniques are essential in achieving optimal performance Proper power supply decoupling and input signal and VREF parameters must be considered for noise contributions SOURCE CODE DESCRIPTION The code written for this simple application performs five main functions: Controller Initialization A/D Converter Conversion Conversion to ASCII Conversion to Decimal Transmit ASCII and Decimal to PC for display Upon power-up the microcontroller Port pins, USART peripheral and SSP module are initialized The default microcontroller SPI bus mode is 1,1 The bus mode can be changed on power-up via SW1 If SW1 is depressed on power-up then PORTC: is pulled low The initialization code checks this pin state and if a logic low SPI bus mode 0,0 is selected Likewise if PORTC: is a logic high, (SW1 is not depressed), then mode 1,1 is the operational bus state Once the initialization code is executed, the main code loop is entered and executed continuously After asserting PORTD: the SPDR register is written to for initiating a SPI bus cycle When the SPI cycle is complete, (SPIF flag is set to logic 1), the received data is read from the SPDR register and written to the RAM variable RESULT_MSB The SPDR register is again written to, which initiates a SPI bus cycle, and the second 8-bits are received and written to the RAM variable RESULT_LSB Here the composite result, located in variables RESULT_MSB and RESULT_LSB is right adjusted one bit location The CS/SHDN is then negated and the MCP3201 enters into the shutdown mode Next the hex_to_ascii and hex_to_decimal routines are called and executed Then the display_conversion routine is executed which sends the data to the USART for transmission to the PC for display REFERENCES Williams, Jim, “Analog Circuit Design,” ButterworthHeinemann Baker, Bonnie, “Layout Tips for 12-bit A/D Converter Applications,” AN688, Microchip Technology Inc MCP3201 12-bit A/D Converter with SPI Serial Interface, Microchip Technology, Document DS21290B, 1999 DS00704B-page  1999 Microchip Technology Inc AN704 APPENDIX A: SOURCE CODE MCP3201.SRC Assembled with IASM 07/01/1999 11:30 PAGE Interfacing Microchip MCP3201 ADC to Motorola MC68HC11E9-Based Microcontroller 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60  1999 Microchip Technology Inc ***************************************************************** * * Filename: MCP3201.src * Date: 07/01/99 * * File Version: 1.00 * * Author: Richard L Fischer * Microchip Technology Inc * ***************************************************************** * * * This code demonstrates how the Microchip MCP3201 Analog-to-Digital * Converter (ADC) is interfaced to the Synchronous Serial Peripheral * (SSP) of the MC68HC11E9 microcontroller The interface uses two * Serial Peripheral Interface (SPI) lines (SCK, MISO) on the * 68HC11E9 Microcontroller for the clock (SCK) and data in (MISO) * A chip select (CS) to the MCP3201 is generated with a general * purpose port line (PD5) The MC68HC11E9 is placed into the master * mode which allows use of the port line PD5 for the CS control * signal The simple application uses Mode 00 or Mode 11 to the * define bus clock polarity and phase * * SPI bus mode 1,1 is the default mode of operation upon power-up * If SPI bus Mode 0,0 is desired, cycle off power, depress and * hold SW1, cycle on power then release SW1 SPI bus Mode 0,0 is * now the operational mode * * For this application, the SPI data rate is set to one eighth of * the microcontroller clock frequency The MC68HC11E9 device clock * frequency used for this application is 8MHz This translates to * an ADC throughput of 62.5kHz In order to obtain the maximum * throughput (100kHz) from the MCP3201 ADC the M68HC11E9 must be * clocked at 12.8Mhz * * ****************************************************************** *********************************************** * MICROCONTROLLER RELATED EQUATES * *********************************************** REGBASE PACTL PORTA PORTB DDRC PORTC DDRD PORTD EQU EQU EQU EQU EQU EQU EQU EQU $1000 $26 $00 $04 $07 $03 $09 $08 ; ; ; ; ; ; ; ; Register Base Address PortA bit7 control PortA Address PortB Address PortD Data Direction Register PortC Address PortD Data Direction Register PortD Address SPCR SPSR SPDR EQU EQU EQU $28 $29 $2A ; SPI Control Register ; SPI Status Register ; SPI Data Register BAUD EQU $2B ; Baud Rate Register DS00704B-page AN704 0000 0000 0000 0000 0000 0000 0001 0002 0003 0004 0005 0006 0025 0025 0025 0025 0025 0025 D000 D000 [03] 8E01FF D003 [06] 7F0000 D006 [06] 7F0001 D009 D00C D010 D013 D015 D016 D018 D01B [03] [04] [05] [04] [03] [04] [04] [03] CE0006 18CED12D 18A600 A700 08 1808 8C0026 26F3 D01D [03] CE1000 D020 D023 D026 D029 [07] [07] [07] [07] 1D00FF 1C2680 1D04FF 1C077F DS00704B-page 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 SCCR2 SCSR SCDR EQU EQU EQU $2D $2E $2F ; SCI Control Register ; SCI Status Register ; SCI Data Register MASKCS EQU $20 ; Mask for Chip Select Bit *********************************************** * INTERNAL RAM USAGE * *********************************************** ORG $0000 ; Internal RAM RESULT_MSB RESULT_LSB RMB RMB 1 ; Converted MSB ; Converted LSB THOUS HUNDS TENS ONES RMB RMB RMB RMB 1 1 ; ; ; ; DISPLAY_BUFF RMB 1F ; Buffer string for display Variable Variable Variable Variable for for for for ASCII ASCII ASCII ASCII thousands hundreds tens ones *********************************************** * INTERNAL MEMORY EQUATES * *********************************************** EEPMBEG EEPMEND EQU EQU $B600 $B7FF ; EEPROM begin ; EEPROM end EPRMBEG EPRMEND EQU EQU $D000 $FFFF ; EPROM begin ; EPROM end RAMBEG RAMEND EQU EQU $0000 $01FF ; RAM begin ; RAM end ***************************************************************** start copy ORG EPRMBEG ; Beginning of code LDS CLR CLR #RAMEND RESULT_MSB RESULT_LSB ; Initialize Stack Pointer ; Clear ram variables ; Clear ram variables LDX LDY LDAA STAA INX INY CPX BNE #DISPLAY_BUFF #DISPLAY_IMAGE 0,Y 0,X #DISPLAY_BUFF+20 copy ; ; ; ; ; ; ; ; LDX #REGBASE ; Initialize X Index pointer BCLR BSET BCLR BSET PORTA,X,$FF PACTL,X,$80 PORTB,X,$FF DDRC,X,$7F ; ; ; ; ; Initialize X pointer to RAM Initialize Y pointer to ROM Read from ROM Save into RAM Point to next RAM location Point to next ROM location Copy display string complete? No, so copy some more Set PortA outputs low Set PortA bit7 to output Set PortB outputs low Set PortC for outputs except for pin7  1999 Microchip Technology Inc AN704 D02C [07] 1D03FF D02F [07] 1C0937 D032 [02] 8620 D034 [04] A708 D036 [07] 1C2D08 D039 [02] 8630 D03B [04] A72B D03D D041 D043 D045 [07] [02] [04] [03] 1E038006 8650 A728 2004 D047 [02] 865C D049 [04] A728 D04B [07] 1D0820 D04E D050 D054 D056 [06] [07] [04] [03] 6F2A 1F2980FC A62A 9700 D058 [06] 6F2A D05A [07] 1F2980FC D05E [07] 1C0820 D061 [04] A62A D063 [03] 9701 D065 [06] 760000 D068 [06] 760001 D06B [06] 1500F0 D06E [06] BDD093 D071 [06] BDD0D3 D074 [04] 18CE0006 D078 [05] 18A600 D07B D07D D081 D083 [04] [07] [04] [05] A72F 1F2E40FC 1808 188C0026 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192  1999 Microchip Technology Inc m11 BCLR BSET PORTC,X,$FF DDRD,X,$37 LDAA STAA #$20 PORTD,X ; ; ; ; ; Set PortC outputs low Make all PortD pins outputs except PD3 BSET LDAA STAA SCCR2,X,$08 #$30 BAUD,X ; Enable SCI TX ; Initialize SCI for 9600 ; baud at 8Mhz BRSET LDAA STAA BRA PORTC,X,$80,m11 #$50 SPCR,X start_conversion ; ; ; ; LDAA STAA #$5C SPCR,X ; Mode 11 ; Initialize SPI control reg Set CS high and all other Branch to Mode 11 if pin high Else, Mode 00 Initialize SPI control reg Go start conversion ******************************************************* * * The routines to follow perform repetitive functions: * * Initiate an ADC conversion sequence * Convert acquired data for display * Transmit converted data to PC * ******************************************************* start_conversion rd1 rd2 ***** BCLR PORTD,X,MASKCS ; Assert CS to ADC CLR BRCLR LDAA STAA SPDR,X SPSR,X,$80,rd1 SPDR,X RESULT_MSB ; ; ; ; Initiate SPI bus cycle Wait until cycle completes Read data and clear flag (SPIF) Save off upper bits CLR SPDR,X BRCLR SPSR,X,$80,rd2 ; Initiate SPI bus cycle ; Wait until cycle completes BSET LDAA STAA PORTD,X,MASKCS SPDR,X RESULT_LSB ; Negate CS, place ADC in shutdown ; Read data and clear flag (SPIF) ; Save off lower bits ROR ROR BCLR RESULT_MSB RESULT_LSB RESULT_MSB,$F0 ; Move bit into carry ; Rotate MSB bit0 into LSB bit7 ; Mask out upper bits of MSB JSR JSR hex_to_ascii hex_to_decimal ; Convert to ASCII for display ; Convert to decimal for display ROUTINE FOR DISPLAYING CONVERTED DATA *********** display_conversion tx_loop wtx LDY LDAA #DISPLAY_BUFF 0,Y STAA SCDR,X BRCLR SCSR,X,$40,wtx INY CPY #DISPLAY_BUFF+20 ; Initialize Y pointer ; Retrieve MSB upper nibble ; ; ; ; Initiate SCI Transmit Wait until cycle completes Increment Y pointer All characters sent? DS00704B-page AN704 D087 [03] 26EF D089 [04] 18CE0000 D08D [04] 1809 D08F [03] 26FC D091 [03] 20B8 D093 D094 D097 D09B D09D D09E D0A0 D0A1 D0A2 D0A3 D0A4 D0A6 D0A8 D0AA D0AD D0AF D0B1 [04] [03] [04] [04] [03] [02] [02] [02] [02] [02] [02] [03] [02] [05] [03] [02] [05] 3C CE0000 18CE000E A600 36 84F0 44 44 44 44 8109 2F07 8B37 18A700 2005 8B30 18A700 D0B4 D0B6 D0B7 D0B9 D0BB D0BD D0BF D0C2 [04] [04] [02] [02] [03] [02] [05] [03] 1808 32 840F 8109 2F07 8B37 18A700 2005 D0C4 [02] 8B30 D0C6 [05] 18A700 D0C9 D0CA D0CC D0CF D0D1 D0D2 D0D3 D0D5 D0D8 D0DB D0DE [03] [04] [04] [03] [05] [05] [04] [06] [06] [06] [06] 08 1808 8C0002 26CA 38 39 DC00 7F0002 7F0003 7F0004 7F0005 D0E1 [05] 1A8303E7 D0E5 [03] 2508 DS00704B-page 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 BNE decy ***** tx_loop ; No, so send more characters LDY #$0000 DEY BNE decy ; Approximately 485mS delay ; Decrement counter ; Stay in loop until Y=0 BRA start_conversion ; Stay in main loop ROUTINE FOR CONVERTING TO ASCII ***************** hex_to_ascii Save off X Index register Initialize X Initialize Y Get Result_MSB data Save ACCA Mask out lower nibble Shift upper nibble into lower nibble #$09 numb_1 #$37 0,Y do_lsb #$30 0,Y ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; INY PULA ANDA CMPA BLE ADDA STAA BRA #$0F #$09 numb_2 #$37 0,Y next1 ; ; ; ; ; ; ; ; Increment Y Restore ACCA Mask out upper nibble Is value a number ? Yes, make it 0-9 ($30 - $39) No, make it a letter (A - F) Save ASCII letter numb_2 ADDA STAA #$30 0,Y ; ; Save ASCII number next1 INX INY CPX BNE PULX RTS #RESULT_MSB+2 next ; ; ; ; ; ; next numb_1 do_lsb ***** PSHX LDX LDY LDAA PSHA ANDA LSRA LSRA LSRA LSRA CMPA BLE ADDA STAA BRA ADDA STAA #RESULT_MSB #DISPLAY_BUFF+8 0,X #$F0 Is value a number ? Yes, make it 0-9 ($30 - $39) No, make it a letter (A - F) Save ASCII letter Convert lower nibble Save ASCII number Increment X Increment Y Converted all bytes? No, so some more Else yes so restore X Return from subroutine ROUTINE FOR CONVERTING TO DECIMAL *************** hex_to_decimal ck_thous LDD CLR CLR CLR CLR RESULT_MSB THOUS HUNDS TENS ONES ; ; ; ; ; Initialize ACCA and ACCB Zero out THOUSANDS temp location Zero out HUNDREDS temp location Zero out TENS temp location Zero out ONES temp location CPD BLO #$03E7 ck_hunds ; ACCD >= 1000 or more? ; No, so go check hundreds  1999 Microchip Technology Inc AN704 D0E7 [04] 8303E8 D0EA [06] 7C0002 D0ED [03] 20F2 D0EF D0F3 D0F5 D0F8 D0FB [05] [03] [04] [06] [03] 1A830063 2508 830064 7C0003 20F2 D0FD D0FF D101 D103 D106 [02] [03] [02] [06] [03] C10A 2507 C00A 7C0004 20F5 D108 D10A D10E D110 D112 D115 D117 D119 D11B D11E D120 D122 D124 D127 D129 D12C [02] [04] [03] [02] [05] [04] [03] [02] [05] [04] [03] [02] [05] [04] [05] [05] CB30 18CE001E 9602 8B30 18A700 1808 9603 8B30 18A700 1808 9604 8B30 18A700 1808 18E700 39 D12D 4865782D 3E203078 20202020 203A2044 6563696D 616C2D3E 20202020 200D0A FFD6 FFD6 FFD8 FFDA FFDC FFDE FFE0 FFE2 FFE4 FFE6 FFE8 FFEA FFEC FFEE FFF0 FFF2 D000 D000 D000 D000 D000 D000 D000 D000 D000 D000 D000 D000 D000 D000 D000 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317  1999 Microchip Technology Inc SUBD INC BRA #$03E8 THOUS ck_thous ; Subtract 1000 from ACCD ; Increment THOUS ; Go check for more ck_hunds CPD BLO SUBD INC BRA #$0063 ck_tens #$0064 HUNDS ck_hunds ; ; ; ; ; ACCD >= 100 OR more? No, so go check tens Subtract 100 from ACCD Increment HUND Go check for more ck_tens CMPB BLO SUBB INC BRA #$0A do_ones #$0A TENS ck_tens ; ; ; ; ; No, ACCB >= 10 or more? No, finish up with ONES Subtract another 10 from B Bump “TENS” Loop again do_ones ADDB LDY LDAA ADDA STAA INY LDAA ADDA STAA INY LDAA ADDA STAA INY STAB RTS #$30 #DISPLAY_BUFF+18 THOUS #$30 0,Y ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Convert ONES to ASCII Initialize Y pointer into buffer DISPLAY_IMAGE HUNDS #$30 0,Y TENS #$30 0,Y 0,Y DB ‘Hex-> 0x Convert THOUS to ASCII Save it Increment Y Convert HUNDS to ASCII Save it Increment Y Convert TENS to ASCII Save it Increment Y Save conversion into string Return from subroutine : Decimal-> ‘,0D,0A *********************************************** * INTERRUPT VECTORS * *********************************************** ORG $FFD6 DW DW DW DW DW DW DW DW DW DW DW DW DW DW DW start start start start start start start start start start start start start start start ; VECTORS ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; SCI Serial System - RIE, TIE, TCIE, ILIE SPI Serial Transfer Complete - SPIE Pulse Accumalator Input Edge - PAII Pulse Accumalator Overflow - PAOVI Timer Overflow - TOI Timer Input Capture 4/Output Compare - I4/O5I Timer Output Compare - OC4I Timer Output Compare - OC3I Timer Output Compare - OC2I Timer Output Compare - OC1I Timer Input Capture - IC3I Timer Input Capture - IC2I Timer Input Capture -IC1I Real Time Interrupt - RTII IRQ (External Pin) DS00704B-page AN704 FFF4 FFF6 FFF8 FFFA FFFC FFFE D000 D000 D000 D000 D000 D000 318 319 320 321 322 323 324 325 326 327 328 0000 DW DW DW DW DW DW start start start start start start ; ; ; ; ; ; XIRQ Pin Software Interrupt Illegal Opcode Trap COP Failure Clock Monitor Fail Reset END Symbol Table BAUD CK_HUNDS CK_TENS CK_THOUS COPY DDRC DDRD DECY DISPLAY_BUFF DISPLAY_CONVERSI DISPLAY_IMAGE DO_LSB DO_ONES EEPMBEG EEPMEND EPRMBEG EPRMEND HEX_TO_ASCII HEX_TO_DECIMAL HUNDS M11 MASKCS NEXT NEXT1 NUMB_1 NUMB_2 ONES PACTL PORTA PORTB PORTC PORTD RAMBEG RAMEND RD1 RD2 REGBASE RESULT_LSB RESULT_MSB SCCR2 SCDR SCSR SPCR SPDR SPSR START START_CONVERSION TENS THOUS TX_LOOP WTX DS00704B-page 10 002B D0EF D0FD D0E1 D010 0007 0009 D08D 0006 D074 D12D D0B4 D108 B600 B7FF D000 FFFF D093 D0D3 0003 D047 0020 D09B D0C9 D0AF D0C4 0005 0026 0000 0004 0003 0008 0000 01FF D050 D05A 1000 0001 0000 002D 002F 002E 0028 002A 0029 D000 D04B 0004 0002 D078 D07D  1999 Microchip Technology Inc AN704 NOTES:  1999 Microchip Technology Inc DS00704B-page 11 Note the following details of the code protection feature on PICmicro® MCUs • • • • • • The PICmicro family meets the specifications contained in the Microchip Data Sheet Microchip believes that its family of PICmicro microcontrollers is one of the most secure products of its kind on the market today, when used in the intended manner and under normal conditions There are dishonest and possibly illegal methods used to breach the code protection feature All of these methods, to our knowledge, require using the PICmicro microcontroller in a manner outside the operating specifications contained in the data sheet The person doing so may be engaged in theft of intellectual property Microchip is willing to work with the customer who is concerned about the integrity of their code Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code Code protection does not mean that we are guaranteeing the product as “unbreakable” Code protection is constantly evolving We at Microchip are committed to continuously improving the code protection features of our product If you have any further questions about this matter, please contact the local sales office nearest to you Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates It is your responsibility to ensure that your application meets with your specifications No representation or warranty is given and no liability is assumed by Microchip Technology Incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise Use of Microchip’s products as critical components in life support systems is not authorized except with express written approval by Microchip No licenses are conveyed, implicitly or otherwise, under any intellectual property rights Trademarks The Microchip name and logo, the Microchip logo, FilterLab, KEELOQ, microID, MPLAB, PIC, PICmicro, PICMASTER, PICSTART, PRO MATE, SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A and other countries dsPIC, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, microPort, Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM, MXDEV, PICC, PICDEM, PICDEM.net, rfPIC, Select Mode and Total Endurance are trademarks of Microchip Technology Incorporated in the U.S.A Serialized Quick Turn Programming (SQTP) is a service mark of Microchip Technology Incorporated in the U.S.A All other trademarks mentioned herein are property of their respective companies © 2002, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved Printed on recycled paper Microchip received QS-9000 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona in July 1999 The Company’s quality system processes and procedures are QS-9000 compliant for its PICmicro® 8-bit MCUs, KEELOQ® code hopping devices, Serial EEPROMs and microperipheral products In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001 certified  2002 Microchip Technology Inc M WORLDWIDE SALES AND SERVICE AMERICAS ASIA/PACIFIC Japan Corporate Office Australia 2355 West Chandler Blvd Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support: 480-792-7627 Web Address: http://www.microchip.com Microchip Technology Australia Pty Ltd Suite 22, 41 Rawson Street Epping 2121, NSW Australia Tel: 61-2-9868-6733 Fax: 61-2-9868-6755 Microchip Technology Japan K.K Benex S-1 6F 3-18-20, Shinyokohama Kohoku-Ku, Yokohama-shi Kanagawa, 222-0033, Japan Tel: 81-45-471- 6166 Fax: 81-45-471-6122 Rocky Mountain China - Beijing 2355 West Chandler Blvd Chandler, AZ 85224-6199 Tel: 480-792-7966 Fax: 480-792-7456 Microchip Technology Consulting (Shanghai) Co., Ltd., Beijing Liaison Office Unit 915 Bei Hai Wan Tai Bldg No Chaoyangmen Beidajie Beijing, 100027, No China Tel: 86-10-85282100 Fax: 86-10-85282104 Atlanta 500 Sugar Mill Road, Suite 200B Atlanta, GA 30350 Tel: 770-640-0034 Fax: 770-640-0307 Boston Lan Drive, Suite 120 Westford, MA 01886 Tel: 978-692-3848 Fax: 978-692-3821 Chicago 333 Pierce Road, Suite 180 Itasca, IL 60143 Tel: 630-285-0071 Fax: 630-285-0075 Dallas 4570 Westgrove Drive, Suite 160 Addison, TX 75001 Tel: 972-818-7423 Fax: 972-818-2924 Detroit Tri-Atria Office Building 32255 Northwestern Highway, Suite 190 Farmington Hills, MI 48334 Tel: 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Rm 1315, 13/F, Shenzhen Kerry Centre, Renminnan Lu Shenzhen 518001, China Tel: 86-755-2350361 Fax: 86-755-2366086 San Jose Hong Kong Microchip Technology Inc 2107 North First Street, Suite 590 San Jose, CA 95131 Tel: 408-436-7950 Fax: 408-436-7955 Microchip Technology Hongkong Ltd Unit 901-6, Tower 2, Metroplaza 223 Hing Fong Road Kwai Fong, N.T., Hong Kong Tel: 852-2401-1200 Fax: 852-2401-3431 New York Toronto 6285 Northam Drive, Suite 108 Mississauga, Ontario L4V 1X5, Canada Tel: 905-673-0699 Fax: 905-673-6509 India Microchip Technology Inc India Liaison Office Divyasree Chambers Floor, Wing A (A3/A4) No 11, O’Shaugnessey Road Bangalore, 560 025, India Tel: 91-80-2290061 Fax: 91-80-2290062 Korea Microchip Technology Korea 168-1, Youngbo Bldg Floor Samsung-Dong, Kangnam-Ku Seoul, Korea 135-882 Tel: 82-2-554-7200 Fax: 82-2-558-5934 Singapore Microchip Technology Singapore Pte Ltd 200 Middle Road #07-02 Prime Centre Singapore, 188980 Tel: 65-334-8870 Fax: 65-334-8850 Taiwan Microchip Technology Taiwan 11F-3, No 207 Tung Hua North Road Taipei, 105, Taiwan Tel: 886-2-2717-7175 Fax: 886-2-2545-0139 EUROPE Denmark Microchip Technology Nordic ApS Regus Business Centre Lautrup hoj 1-3 Ballerup DK-2750 Denmark Tel: 45 4420 9895 Fax: 45 4420 9910 France Microchip Technology SARL Parc d’Activite du Moulin de Massy 43 Rue du Saule Trapu Batiment A - ler Etage 91300 Massy, France Tel: 33-1-69-53-63-20 Fax: 33-1-69-30-90-79 Germany Microchip Technology GmbH Gustav-Heinemann Ring 125 D-81739 Munich, Germany Tel: 49-89-627-144 Fax: 49-89-627-144-44 Italy Microchip Technology SRL Centro Direzionale Colleoni Palazzo Taurus V Le Colleoni 20041 Agrate Brianza Milan, Italy Tel: 39-039-65791-1 Fax: 39-039-6899883 United Kingdom Arizona Microchip Technology Ltd 505 Eskdale Road Winnersh Triangle Wokingham Berkshire, England RG41 5TU Tel: 44 118 921 5869 Fax: 44-118 921-5820 01/18/02  2002 Microchip Technology Inc [...]... Sheet Microchip believes that its family of PICmicro microcontrollers is one of the most secure products of its kind on the market today, when used in the intended manner and under normal conditions There are dishonest and possibly illegal methods used to breach the code protection feature All of these methods, to our knowledge, require using the PICmicro microcontroller in a manner outside the operating... intellectual property Microchip is willing to work with the customer who is concerned about the integrity of their code Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code Code protection does not mean that we are guaranteeing the product as “unbreakable” Code protection is constantly evolving We at Microchip are committed to continuously improving the code protection... sales office nearest to you Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates It is your responsibility to ensure that your application meets with your specifications No representation or warranty is given and no liability is assumed by Microchip Technology Incorporated with respect to the accuracy or... Technology Inc 2107 North First Street, Suite 590 San Jose, CA 95131 Tel: 408-436-7950 Fax: 408-436-7955 Microchip Technology Hongkong Ltd Unit 901-6, Tower 2, Metroplaza 223 Hing Fong Road Kwai Fong, N.T., Hong Kong Tel: 852-2401-1200 Fax: 852-2401-3431 New York Toronto 6285 Northam Drive, Suite 108 Mississauga, Ontario L4V 1X5, Canada Tel: 905-673-0699 Fax: 905-673-6509 India Microchip Technology Inc India... 770-640-0034 Fax: 770-640-0307 Boston 2 Lan Drive, Suite 120 Westford, MA 01886 Tel: 978-692-3848 Fax: 978-692-3821 Chicago 333 Pierce Road, Suite 180 Itasca, IL 60143 Tel: 630-285-0071 Fax: 630-285-0075 Dallas 4570 Westgrove Drive, Suite 160 Addison, TX 75001 Tel: 972-818-7423 Fax: 972-818-2924 Detroit Tri-Atria Office Building 32255 Northwestern Highway, Suite 190 Farmington Hills, MI 48334 Tel: 248-538-2250... registered trademarks of Microchip Technology Incorporated in the U.S.A and other countries dsPIC, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, microPort, Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM, MXDEV, PICC, PICDEM, PICDEM.net, rfPIC, Select Mode and Total Endurance are trademarks of Microchip Technology Incorporated in the U.S.A Serialized Quick Turn Programming... by Microchip Technology Incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise Use of Microchip’s products as critical components in life support systems is not authorized except with express written approval by Microchip No licenses are conveyed, implicitly or otherwise, under any intellectual... Karman, Suite 1090 Irvine, CA 92612 Tel: 949-263-1888 Fax: 949-263-1338 China - Chengdu Microchip Technology Consulting (Shanghai) Co., Ltd., Chengdu Liaison Office Rm 2401, 24th Floor, Ming Xing Financial Tower No 88 TIDU Street Chengdu 610016, China Tel: 86-28-6766200 Fax: 86-28-6766599 China - Fuzhou Microchip Technology Consulting (Shanghai) Co., Ltd., Fuzhou Liaison Office Unit 28F, World Trade Plaza... Microchip Technology Consulting (Shanghai) Co., Ltd Room 701, Bldg B Far East International Plaza No 317 Xian Xia Road Shanghai, 200051 Tel: 86-21-6275-5700 Fax: 86-21-6275-5060 China - Shenzhen 150 Motor Parkway, Suite 202 Hauppauge, NY 11788 Tel: 631-273-5305 Fax: 631-273-5335 Microchip Technology Consulting (Shanghai) Co., Ltd., Shenzhen Liaison Office Rm 1315, 13/F, Shenzhen Kerry Centre, Renminnan... July 1999 The Company’s quality system processes and procedures are QS-9000 compliant for its PICmicro® 8-bit MCUs, KEELOQ® code hopping devices, Serial EEPROMs and microperipheral products In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001 certified  2002 Microchip Technology Inc M WORLDWIDE SALES AND SERVICE AMERICAS ASIA/PACIFIC Japan Corporate ... Tel: 6 1-2 -9 86 8-6 733 Fax: 6 1-2 -9 86 8-6 755 Microchip Technology Japan K.K Benex S-1 6F 3-1 8-2 0, Shinyokohama Kohoku-Ku, Yokohama-shi Kanagawa, 22 2-0 033, Japan Tel: 8 1-4 5-4 7 1- 6166 Fax: 8 1-4 5-4 7 1-6 122... A - ler Etage 91300 Massy, France Tel: 3 3-1 -6 9-5 3-6 3-2 0 Fax: 3 3-1 -6 9-3 0-9 0-7 9 Germany Microchip Technology GmbH Gustav-Heinemann Ring 125 D-81739 Munich, Germany Tel: 4 9-8 9-6 2 7-1 44 Fax: 4 9-8 9-6 2 7-1 4 4-4 4... 9 1-8 0-2 290061 Fax: 9 1-8 0-2 290062 Korea Microchip Technology Korea 16 8-1 , Youngbo Bldg Floor Samsung-Dong, Kangnam-Ku Seoul, Korea 13 5-8 82 Tel: 8 2-2 -5 5 4-7 200 Fax: 8 2-2 -5 5 8-5 934 Singapore Microchip