Using the 93LC56 and 93LC66 AN560 Using the 93LC56 and 93LC66 INTRODUCTION 3-Wire Byte Write Program The Microchip Technology Inc. 93LC56/66 are lowpower 3-wire non-volatile memories and are suitable for many embedded system code and data storage applications. These devices are easily interfaced to most microcontrollers in today's market place, but Microchip’s 8-bit RISC series PIC16CXX offers the best code density of any microcontroller on the market today. Using the PIC16C54, the assembly programs contained in this application note have been fully tested and provide the correct timing and 3-wire sequences to fully operate the 93LC56/66 in a PIC16CXX-based embedded application. The PIC16C54 was clocked at a 10MHz frequency. This application note is intended to provide the engineer with readily available stand-alone code modules to accomplish all of the necessary functions to utilize these devices in a low power application using the efficient PIC16C54 microcontroller. – Delay Routine The 93 series of devices have essentially four I/O pins: – Transmit Data Routine CS Chip Select – Power-up Routine CLK Clock – Erase/Write Enable Routine DI Data In – Write Routine DO Data Out – Erase/Write Disable Routine (EWDS) – Start Bit Routine – Bit Out Routine – Transmit Data Routine – Power-up Routine – Erase/Write Enable Routine (EWEN) – Byte Write Routine – Erase/Write Disable Routine (EWDS) 3-Wire Byte Write with Data Polling Program – Data Polling Delay Routine – Start Bit Routine – Bit Out Routine This series of devices use a series of commands to accomplish the normal memory functions. These are READ, WRITE, EWEN, ERASE, ERAL, WRAL, EWDS. For a more detailed discussion of the function of these devices reference the appropriate data sheet and AN536, also published by Microchip Technology. 3-Wire Sequential Read Program The following programs are included in this application note and are fully functional stand-alone modules. They are intended for use by those who are not already familiar with interfacing a PIC16CXX microcontroller to a 93 series device. For those with more experience, please refer to application note AN530. – Receive Data Routine – Delay Routine – Start Bit Routine – Bit In Routine 8 – Bit Out Routine – Transmit Data Routine – Power-up Routine – Read Routine 3-Wire Byte Read Program – Start Bit Routine – Receive Data Routine Author: – Bit Out Routine – Transmit Data Routine Bruce Negley Memory Products Division – Power-up Routine – Read Routine © 1994 Microchip Technology Inc. DS00560D-page 1 8-99 Using the 93LC56 and 93LC66 16c5x/7x Cross-Assembler V4.12 Released Line PC 0001 0002 0003 0004 0005 0006 0007 0008 0009 0010 0011 0012 0013 0014 0015 0016 0017 0018 0019 0020 0021 0022 0023 0024 0025 0026 0027 0028 0029 0030 0031 0032 0033 0034 0035 0036 0037 0038 0039 0040 0041 0042 0043 0044 0045 0046 0047 0048 0049 0050 0051 LIST P=16C54,c=132 ;**************************************************************** ; 3-Wire Byte Read Program (80 bytes) ; ; This program demonstrates how to interface a ; Microchip PIC16C54 to a 93LC56 or 93LC66 Serial EE ; device. This program will read 8 consecutive addresses ; in the ‘random read’ mode. This means that the opcode ; and address for each byte will be sent to the device. ; This program will repeat forever. ; ; Another, more efficient method of reading consecutive ; addresses is called the ‘sequential read’ mode. This ; involves sending the opcode and address for the first ; byte to read, then continuing to provide clocks for the ; next addresses. The device will automatically increment ; the address. An example of the sequential read mode is ; provided in the ‘3wseqr.asm’ file. ; ; This program communicates to the serial EE in the ; x16 mode, and ASSUMES THE USER HAS SET THE ORG PIN ; ON THE DEVICE TO Vcc. ; ; Timing is based on using the PIC16C54 in ‘XT’ mode ; using a 4Mhz crystal. Clock speeds to the serial EE ; will be approximately 50 kHz for this setup. ; ; PIC16C54 to Serial EE Connections: ; ; PIC16C54 Serial EE ; —————— —————— ; Pin 10 (RB4) —> Chip Select ; Pin 11 (RB5) —> Clock ; Pin 12 (RB6) —> Data In ; Pin 13 (RB7) —> Data Out ; ORG = Vcc ; ;************************************************************ ; Register Assignments ;************************************************************ status equ 3h ; status register port_a equ 5h ; port 5 (port_a) port_b equ 6h ; port 6 (port b) comm lines to serial EE eeprom equ 0ah ; bit buffer addr equ 0ch ; address register datai equ 0dh ; stored data input reg. datao equ 0eh ; stored data output reg. txbuf equ 10h ; transmit buffer count equ 11h ; bits transmitted so far bits equ 12h ; bits to transmit bytcnt equ 13h ; byte counter for read routine 0003 0005 0006 000A 000C 000D 000E 0010 0011 0012 0013 0052 0053 0054 0055 0056 0057 0058 0059 0060 PC Page 1 Opcode 16c5x/7x Cross-Assembler V4.12 Released Line Mon Jun 06 10:49:10 1994 Mon Jun 06 10:49:10 1994 Page 2 Opcode 0015 0016 0017 0018 0007 0006 loops equ 15h ; delay loop counter loops2 equ 16h ; delay loop counter hbyte equ 17h ; high byte for input data lbyte equ 18h ; low byte for input data ;************************************************************ ; Bit Assignments ;************************************************************ di equ 7 ; eeprom input do equ 6 ; eeprom output DS00560D-page 2 © 1994 Microchip Technology Inc. 8-100 Using the 93LC56 and 93LC66 0061 0062 0063 0064 0065 0066 0067 0068 0069 0070 0071 0072 0073 0074 0075 0076 0077 0078 0079 0080 0081 0082 0083 0084 0085 0086 0087 0088 0089 0090 0091 0092 0093 0094 0095 0096 0097 0098 0099 0100 0101 0102 0007 0006 0005 0004 0000 0000 0A33 0000 0A33 0001 0002 0003 0004 04C6 0486 04A6 0000 0005 0006 0007 0008 0586 05C6 0000 05A6 0009 000A 000B 000C 0000 0000 04A6 0800 000D 000E 000F 0010 0011 05EA 05A6 0000 07E6 04EA 01FF datout equ 7 ; data out line (port_b) datin equ 6 ; data in line (port_b) sclk equ 5 ; clock line (port_b) chpsel equ 4 ; chip select line (port_b) ; ;************************************************************* org 01ffh begin goto PWRUP ; set the reset vector org 000h goto PWRUP ; ;************************************************************** ; Start Bit Subroutine ; this routine generates a start bit ; (Chip select and DI high when clock goes high) ;************************************************************** BSTART bcf port_b,datin ; set datain and chipselect lines bcf port_b,chpsel ; low just to check operation bcf port_b,sclk ; make sure clock starts low too. nop ; bsf port_b,chpsel ; set chip select line high bsf port_b,datin ; set data in line high nop bsf port_b,sclk ; set the clock line high to ; generate the start bit nop nop bcf port_b,sclk ; set clock low again retlw 0 ; ;************************************************************** ; BITIN routine reads one bit of data from the ; serial EE device and stores it in ‘di’ ;************************************************************** BITIN bsf eeprom,di ; assume input bit is high bsf port_b,sclk ; set clock line high nop ; btfss port_b,datout ; read the data bit bcf eeprom,di ; input bit was low 16c5x/7x Cross-Assembler V4.12 Released Mon Jun 06 10:49:10 1994 Line PC Opcode 0103 0104 0105 0106 0107 0108 0109 0110 0111 0112 0113 0114 0115 0116 0117 0118 0119 0120 0121 0122 0123 0124 0012 04A6 bcf port_b,sclk 0013 0800 retlw 0 0014 0015 0016 0017 0018 0019 001A 001B 001C 001D 001E 001F 006D 0C08 0031 0403 036D 090D 040D 06EA 050D 02F1 0A18 0800 Page 3 8 ; set clock line low ; ; ;**************************************************************** ; Receive data routine ; This routine reads one byte of data from the part ; into the ‘datai’ register. ;**************************************************************** RX clrf datai ; clear input buffer movlw .8 ; set # bits to 8 movwf count bcf status,0 ; make sure carry bit is low RXLP rlf datai ; rotate the buffer left 1 bit call BITIN ; read 1 bit bcf datai,0 ; assume the input bit was low btfsc eeprom,di ; check the bit bsf datai,0 ; set high if neccessary decfsz count ; 8 bits done? goto RXLP ; no, do another retlw 0 © 1994 Microchip Technology Inc. DS00560D-page 3 8-101 Using the 93LC56 and 93LC66 0125 0126 0127 0128 0129 0130 0131 0132 0133 0134 0135 0136 0137 0138 0139 0140 0141 0142 0143 0144 0145 0146 0147 0148 0149 0150 0151 0152 0153 0020 0021 0022 0023 07CA 0A24 05C6 0A25 0024 0025 0026 0027 0028 04C6 05A6 0000 04A6 0800 0029 002A 0212 0031 002B 04CA ; ;************************************************************* ; BITOUT routine ; This routine takes one bit of data in ‘do’ and ; transmits it to the serial EE device ;************************************************************* BITOUT btfss eeprom,do ; check state of data bit goto bitlow ; low, goto bitlow bsf port_b,datin ; high, set datain high goto clkout ; and clock it ; bitlow bcf port_b,datin ; output a logic low clkout bsf port_b,sclk ; set clock line high nop bcf port_b,sclk ; return clock line low retlw 0 ; ;**************************************************************** ; Transmit Data Subroutine ; This routine takes the byte of data stored in the ; ‘datao’ register and transmits it to the serial EE device. ;**************************************************************** TX movf bits,w ; set the number of bits to xmit movwf count ; TXLP bcf eeprom,do ; assume bit 7 is low 16c5x/7x Cross-Assembler V4.12 Released Line PC Opcode 0154 0155 0156 0157 0158 0159 0160 0161 0162 0163 0164 0165 0166 0167 0168 0169 0170 0171 0172 0173 0174 0175 0176 0177 0178 0179 0180 0181 0182 0183 0184 0185 0186 0187 0188 002C 002D 002E 002F 0030 0031 0032 06F0 05CA 0920 0370 02F1 0A2B 0800 0033 0034 0035 0C00 0005 0065 0036 0037 0C80 0006 0038 0039 0C00 002C btfsc bsf call rlf decfsz goto retlw Mon Jun 06 10:49:10 1994 txbuf,7 eeprom,do BITOUT txbuf count TXLP 0 ; ; ; ; ; ; ; Page 4 is bit 7 clear? no, set data bit =1 transmit 1 bit to serial EE rotate txbuf left all bits done? no, do another bit yes, jump out ; ;**************************************************************** ; POWER-UP ROUTINE ; This is the program entry point, which in this case simply ; sets the port_a I/O lines and directs control to the ; read routine. ;***************************************************************** PWRUP ; movlw b’00000000' tris port_a ; set port_a as all output clrf port_a ; all lines low movlw tris b’10000000' port_b ; set RB7 as input, rest output; ; ; Fall through and do the read ; ;********************************************************************* ; READ ROUTINE ; This routine reads 8 consecutive addresses in ; random mode starting at address 0. This is done in ; x16 mode and will repeat forever. ;********************************************************************* READ ; movlw .0 ; set starting address to 00 movwf addr ; DS00560D-page 4 © 1994 Microchip Technology Inc. 8-102 Using the 93LC56 and 93LC66 0189 0190 0191 0192 0193 0194 0195 0196 0197 0198 0199 0200 0201 0202 0203 0204 003A 003B 0C08 0033 003C 003D 003E 003F 0040 0041 0042 0043 0044 0045 0046 0901 0C02 0032 0C80 0030 0929 0C08 0032 020C 0030 0929 0047 0914 rbyte movlw movwf .8 bytcnt call movlw movwf movlw movwf call movlw movwf movf movwf call BSTART .2 bits b’10000000' txbuf TX .8 bits addr,w txbuf TX ; ; ; ; ; ; ; ; ; ; ; ; ; ; call RX ; read the high byte 16c5x/7x Cross-Assembler V4.12 Released set number of addresses to read as 8 generate the start bit set # bits to 2 get opcode (10b) into output buffer and transmit it set number of bits to 8 get the address into the output buffer and transmit it Mon Jun 06 10:49:10 1994 Page 5 Line PC Opcode 0205 0206 0207 0208 0209 0210 0211 0212 0213 0214 0215 0216 0217 0218 0048 0049 020D 0037 movf movwf datai,w hbyte ; move input data to w ; xfer it to high byte 004A 004B 004C 0914 020D 0037 call movf movwf RX datai,w hbyte ; read the low byte ; move input data to w ; xfer it to low byte 004D 0486 bcf port_b,chpsel ; clear the chip select line 004E 004F 0050 0051 02AC 02F3 0A3C 0A38 0000 incf decfsz goto goto addr bytcnt rbyte READ ; ; ; ; add 1 to the address have all bytes been read? no, read another byte yes, start over END 8 © 1994 Microchip Technology Inc. DS00560D-page 5 8-103 Using the 93LC56 and 93LC66 16c5x/7x Cross-Assembler V4.12 Released Line PC 0001 0002 0003 0004 0005 0006 0007 0008 0009 0010 0011 0012 0013 0014 0015 0016 0017 0018 0019 0020 0021 0022 0023 0024 0025 0026 0027 0028 0029 0030 0031 0032 0033 0034 0035 0036 0037 0038 0039 0040 0041 0042 0043 0044 0045 0046 0047 0048 0049 0050 0051 LIST P=16C54,c=132 ;**************************************************************** ; 3-Wire Byte Write Program (106 bytes) ; ; This program demonstrates how to interface a ; Microchip PIC16C54 to a 93LC56 or 93LC66 Serial EE ; device. This program will execute the erase/write enable ; command, write to 8 consecutive addresses, and then ; execute the erase/write disable command. This ; sequence will repeat forever. ; ; After each byte is written, time must be given to the ; device for it to complete the write cycle before ; the next command can be sent. The easiest solution ; is to consult the data book for the maximum write ; cycle time and just wait that long before the next ; command is sent. This program demonstrates that ; solution. ; ; Another, more efficient method of determining when the ; write cycle is complete is called ‘data polling.’ This ; method is demonstrated in the program “3wdpoll.” ; ; This program communicates to the serial EE in the ; x16 mode, and ASSUMES THE USER HAS SET THE ORG PIN ; ON THE DEVICE TO Vcc. ; ; Timing is based on using the PIC16C54 in ‘XT’ mode ; using a 4Mhz crystal. Clock speeds to the serial EE ; will be approximately 40 kHz for this setup. ; ; PIC16C54 to Serial EE Connections: ; ; PIC16C54 Serial EE ; —————— —————— ; Pin 10 (RB4) —> Chip Select ; Pin 11 (RB5) —> Clock ; Pin 12 (RB6) —> Data In ; Pin 13 (RB7) —> Data Out ; ORG=Vcc ; ;************************************************************ ; Register Assignments ;************************************************************ port_a equ 5h ; port 5 (port_a) port_b equ 6h ; port 6 (port b) comm lines to serial EE eeprom equ 0ah ; bit buffer addr equ 0ch ; address register datai equ 0dh ; stored data input reg. datao equ 0eh ; stored data output reg. txbuf equ 10h ; transmit buffer 0005 0006 000A 000C 000D 000E 0010 0052 0053 0054 0055 0056 0057 0058 0059 0060 PC Page 1 Opcode 16c5x/7x Cross-Assembler V4.12 Released Line Mon Jun 06 10:49:06 1994 Mon Jun 06 10:49:06 1994 Page 2 Opcode 0011 0012 0013 0015 0016 0007 count equ 11h ; bits transmitted so far bits equ 12h ; bits to transmit bytcnt equ 13h ; byte counter for write routine loops equ 15h ; delay loop counter loops2 equ 16h ; delay loop counter ; ;************************************************************ ; Bit Assignments ;************************************************************ di equ 7 ; eeprom input DS00560D-page 6 © 1994 Microchip Technology Inc. 8-104 Using the 93LC56 and 93LC66 0061 0062 0063 0064 0065 0066 0067 0068 0069 0070 0071 0072 0073 0074 0075 0076 0077 0078 0079 0080 0081 0082 0083 0084 0085 0086 0087 0088 0089 0090 0091 0092 0093 0094 0095 0096 0097 0098 0099 0100 0101 0102 0006 0007 0006 0005 0004 0000 0000 0A2F 0000 0A2F 0001 0002 0003 0004 0005 0006 0007 0008 0009 000A 0C6E 0036 0000 0000 0000 0000 0000 0000 02F6 0A03 000B 000C 000D 02F5 0A01 0800 000E 0C8F 01FF do equ 6 ; eeprom output datout equ 7 ; data out line (port_b) datin equ 6 ; data in line (port_b) sclk equ 5 ; clock line (port_b) chpsel equ 4 ; chip select line (port_b) ; ;************************************************************* org 01ffh begin goto PWRUP ; set the reset vector org 000h goto PWRUP ; ;************************************************************* ; DELAY ROUTINE ; This routine takes the value in ‘loops’ ; and multiplies it times 1 millisecond to ; determine delay time. ;************************************************************* WAIT ; top movlw .110 ; timing adjustment variable movwf loops2 top2 nop ; sit and wait nop nop nop nop nop decfsz loops2 ; inner loops complete? goto top2 ; no, go again ; decfsz loops ; outer loops complete? goto top ; no, go again retlw 0 ; yes, return from sub ; ;************************************************************** ; Start Bit Subroutine ; this routine generates a start bit ; (Chip select and DI high when clock goes high) ;**************************************************************; BSTART movlw b’10001111' 16c5x/7x Cross-Assembler V4.12 Released Mon Jun 06 10:49:06 1994 Page 3 Line PC Opcode 0103 0104 0105 0106 0107 0108 0109 0110 0111 0112 0113 0114 0115 0116 0117 0118 0119 0120 0121 0122 0123 0124 000F 0006 tris port_b 0010 0011 0012 0013 04C6 0486 04A6 0000 bcf bcf bcf nop port_b,datin port_b,chpsel port_b,sclk ; ; ; ; ; 0014 0015 0016 0017 0586 05C6 0000 05A6 bsf bsf nop bsf port_b,chpsel port_b,datin ; set chip select line high ; set data in line high port_b,sclk ; set the clock line high to ; generate the start bit 0018 0019 001A 001B 0000 0000 04A6 0800 set port b for output except for the data out line set datain and chipselect lines low just to check operation make sure clock starts low too. ; nop nop bcf port_b,sclk ; set clock low again retlw 0 ; ;************************************************************* ; BITOUT routine ; This routine takes one bit of data in ‘do’ and ; transmits it to the serial EE device ;************************************************************* © 1994 Microchip Technology Inc. DS00560D-page 7 8-105 8 Using the 93LC56 and 93LC66 0125 0126 0127 0128 0129 0130 0131 0132 0133 0134 0135 0136 0137 0138 0139 0140 0141 0142 0143 0144 0145 0146 0147 0148 0149 0150 0151 0152 0153 BITOUT 001C 001D 001E 001F 07CA 0A20 05C6 0A21 0020 0021 0022 0023 0024 04C6 05A6 0000 04A6 0800 0025 0026 0212 0031 0027 0028 0029 002A 002B 002C 002D 04CA 06F0 05CA 091C 0370 02F1 0A27 bitlow clkout btfss goto bsf goto eeprom,do bitlow port_b,datin clkout bcf bsf nop bcf retlw port_b,datin port_b,sclk port_b,sclk 0 ; ; ; ; ; ; ; check state of data bit low, goto bitlow high, set datain high and clock it output a logic low set clock line high ; return clock line low ; ;**************************************************************** ; Transmit Data Subroutine ; This routine takes the byte of data stored in the ; ‘datao’ register and transmits it to the serial EE device. ;**************************************************************** TX movf bits,w ; set the number of bits to xmit movwf count ; TXLP bcf eeprom,do ; assume bit 7 is low btfsc txbuf,7 ; is bit 7 clear? bsf eeprom,do ; no, set data bit =1 call BITOUT ; transmit 1 bit to serial EE rlf txbuf ; rotate txbuf left decfsz count ; all bits done? goto TXLP ; no, do another bit 16c5x/7x Cross-Assembler V4.12 Released Line PC Opcode 0154 0155 0156 0157 0158 0159 0160 0161 0162 0163 0164 0165 0166 0167 0168 0169 0170 0171 0172 0173 0174 0175 0176 0177 0178 0179 0180 0181 0182 0183 0184 0185 0186 0187 0188 002E 0800 002F 0030 0031 0C00 0005 0065 0032 0033 0C80 0006 0034 090E 0035 0036 0037 0038 0039 003A 0C02 0032 0C00 0030 0925 0C08 Mon Jun 06 10:49:06 1994 Page 4 retlw 0 ; yes, jump out ; ;**************************************************************** ; POWER-UP ROUTINE ; This is the program entry point, which in this case simply ; sets the port_a I/O lines and directs control to the ; erase/write enable routine. ;***************************************************************** PWRUP ; movlw b’00000000' tris port_a ; set port_a as all output clrf port_a ; all lines low movlw tris b’10000000' port_b ; set RB7 as input, rest output; ; ; Fall through and do erase/write enable ; ;**************************************************************** ; EWEN (Erase/Write ENable Routine) ; this routine enables the dut for erasing and ; writing. This must be done prior to any erase,write ; eral,wral instructions. ;**************************************************************** EWEN ; call BSTART ; generate a start bit ; movlw .2 ; set # bits to 2 movwf bits ; movlw b’00000000' ; get the opcode (00b) movwf txbuf ; into the output buffer call TX ; and transmit it movlw .8 ; set # bits to 8 DS00560D-page 8 © 1994 Microchip Technology Inc. 8-106 Using the 93LC56 and 93LC66 0189 0190 0191 0192 0193 0194 0195 0196 0197 0198 0199 0200 0201 0202 0203 0204 003B 003C 0032 0CC0 movwf movlw bits b’11000000' 003D 003E 003F 0040 0030 0925 0486 0000 movwf call bcf nop txbuf TX port_b,chpsel 0205 0206 0207 0208 0209 0210 0211 0212 0213 0214 0215 0216 0217 0218 0219 0220 0221 0222 0223 0224 0225 0226 0227 0228 0229 0230 0231 0232 0233 0234 0235 0236 0237 0238 0239 0240 0241 0242 0243 0244 0245 0246 0247 0248 0249 0250 0251 0252 get opcode and address (11XXXXXX) into output buffer and transmit it set chip select line low ; ; Now continue on to the write command ; ;************************************************************** ; Byte Write Routine ; This routine writes an AA55h pattern into ; 8 consecutive addresses starting at address 00. ; A delay of about 10ms is given after each byte ; for the write cycle to complete. 16c5x/7x Cross-Assembler V4.12 Released Line ; ; ; ; ; ; PC Mon Jun 06 10:49:06 1994 Page 5 Opcode 0041 0042 0043 0044 0C00 002C 0C08 0033 0045 090E 0046 0047 0048 0049 004A 0C02 0032 0C40 0030 0925 004B 004C 004D 004E 004F 0050 0051 0052 0053 0054 0055 0C08 0032 020C 0030 0925 0CAA 0030 0925 0C55 0030 0925 0056 0486 0057 0058 0059 0C0A 0035 0901 005A 005B 005C 02AC 02F3 0A45 ; The write is done in the x16 mode: the user must ; have the ORG pin tied to Vcc on the device ;**************************************************************** WRITE ; movlw .0 ; set starting address to 00 movwf addr ; movlw .8 ; set number of bytes to write as 8 movwf bytcnt ; ; topwr call BSTART ; generate the start bit ; movlw .2 ; set # bits to 2 for the opcode movwf bits ; movlw b’01000000' ; get opcode (01b) movwf txbuf ; into the transmit buffer call TX ; and send it ; movlw .8 ; set # of bits to 8 for the movwf bits ; address movf addr,w ; get address counter movwf txbuf ; into output buffer call TX ; and send it movlw b’10101010' ; get upper byte of data (AAh) movwf txbuf ; into the transmit buffer call TX ; and send it movlw b’01010101' ; get lower byte of data (55h) movwf txbuf ; into transmit buffer call TX ; and send it ; bcf port_b,chpsel ; clear the chip select line ; to initiate write cycle ; movlw .10 ; movwf loops ; set delay time to 10mS call WAIT ; and wait ; incf addr ; increment address counter decfsz bytcnt ; all bytes written? goto topwr ; no, do another ; yes, go on ; ; Now continue on to the erase/write disable command ; ;**************************************************************** ; EWDS (Erase/Write Disable Routine) ; This routine executes the erase/write disable command ; which prevents the contents of the array from being © 1994 Microchip Technology Inc. DS00560D-page 9 8-107 8 Using the 93LC56 and 93LC66 0253 0254 0255 ; written to. ; ;**************************************************************** 16c5x/7x Cross-Assembler V4.12 Released Line 0256 0257 0258 0259 0260 0261 0262 0263 0264 0265 0266 0267 0268 0269 0270 0271 0272 0273 0274 0275 PC Mon Jun 06 10:49:06 1994 Page 6 Opcode EWDS ; 005D 090E call BSTART ; generate a start bit ; 005E 005F 0060 0061 0062 0063 0064 0065 0C02 0032 0C00 0030 0925 0C08 0032 0C00 movlw movwf movlw movwf call movlw movwf movlw .2 bits b’00000000' txbuf TX .8 bits b’00000000' 0066 0067 0068 0069 006A 0030 0925 0486 0000 0A34 movwf call bcf nop goto txbuf TX port_b,chpsel ; ; ; ; ; ; ; ; ; ; ; ; EWEN ; start all over 0000 set # bits to 2 get the opcode (00b) into the output buffer and transmit it set # bits to 8 get opcode and address (00XXXXXX) into output buffer and transmit it set chip select line low ; END DS00560D-page 10 © 1994 Microchip Technology Inc. 8-108 Using the 93LC56 and 93LC66 16c5x/7x Cross-Assembler V4.12 Released Line PC LIST P=16C54,c=132 ;**************************************************************** ; 3-Wire Byte Write with Data Poll Program (107 bytes) ; ; This program demonstrates how to interface a ; Microchip PIC16C54 to a 93LC56 or 93LC66 Serial EE ; device. This program will execute the erase/write enable ; command, write to 8 consecutive addresses, and then ; use the ‘data polling’ method to determine when the ; write cycle is complete. The program then executes ; the erase/write disable command. This sequence will ; repeat forever. ; ; When writing to a 3-wire serial EE device, the ; internally timed write cycle will begin after ; the opcode, address and data are sent to the ; device. There are two ways to make sure that the ; cycle is complete before you send it another command. ; The simplest method is to simply wait for the maximum ; write cycle time, which can be obtained from the data book. ; A more efficient method is “Data polling.” This is ; done by toggling the chip select line low and then ; back high after the opcode, address and data are sent. ; The chip select line must be low for at least 250ns ; before bringing it high again. The device will pull ; the data out line low at that point, and set it high ; when the write cycle is complete. The user can then check ; or “poll” the dataout line until it goes high before ; sending the next command. ; ; As an option, the user can connect a LED to pin 18 ; on the PIC16C54 (use about a 1K resistor in series) as a ; timeout indicator. This LED will come on if the ; data polling is unsuccessful and the device being ; programmed does not respond. This can be tested by ; simply running the program with no part in the socket. ; ; This program communicates to the serial EE in the ; x16 mode, and ASSUMES THE USER HAS SET THE ORG PIN ; ON THE DEVICE TO Vcc. ; ; Timing is based on using the PIC16C54 in ‘XT’ mode ; using a 4Mhz crystal. Clock speeds to the serial EE ; will be approximately 50 kHz for this setup. ; ; PIC16C54 to Serial EE Connections: ; ; PIC16C54 Serial EE ; —————— —————— ; Pin 10 (RB4) —> Chip Select ; Pin 11 (RB5) —> Clock 16c5x/7x Cross-Assembler V4.12 Released 0052 0053 0054 0055 0056 0057 0058 0059 0060 Page 1 Opcode 0001 0002 0003 0004 0005 0006 0007 0008 0009 0010 0011 0012 0013 0014 0015 0016 0017 0018 0019 0020 0021 0022 0023 0024 0025 0026 0027 0028 0029 0030 0031 0032 0033 0034 0035 0036 0037 0038 0039 0040 0041 0042 0043 0044 0045 0046 0047 0048 0049 0050 0051 Line Mon Jun 06 10:49:00 1994 PC Mon Jun 06 10:49:00 1994 Page 2 Opcode 0005 0006 ; Pin 12 (RB6) —> Data In ; Pin 13 (RB7) —> Data Out ; ORG=Vcc ; ;************************************************************ ; Register Assignments ;************************************************************ port_a equ 5h ; port 5 (port_a) port_b equ 6h ; port 6 (port b) used comm lines to serial EE © 1994 Microchip Technology Inc. DS00560D-page 11 8-109 8 Using the 93LC56 and 93LC66 0061 0062 0063 0064 0065 0066 0067 0068 0069 0070 0071 0072 0073 0074 0075 0076 0077 0078 0079 0080 0081 0082 0083 0084 0085 0086 0087 0088 0089 0090 0091 0092 0093 0094 0095 0096 0097 0098 0099 0100 0101 0102 000A 000C 000D 000E 0010 0011 0012 0013 0015 0016 0007 0006 0007 0006 0005 0004 0001 eeprom equ 0ah ; bit buffer addr equ 0ch ; address register datai equ 0dh ; stored data input reg. datao equ 0eh ; stored data output reg. txbuf equ 10h ; transmit buffer count equ 11h ; bits transmitted so far bits equ 12h ; bits to transmit bytcnt equ 13h ; byte counter for write routine loops equ 15h ; delay loop counter loops2 equ 16h ; delay loop counter ;************************************************************ ; Bit Assignments ;************************************************************ di equ 7 ; eeprom input do equ 6 ; eeprom output datout equ 7 ; data out line (port_b) datin equ 6 ; data in line (port_b) sclk equ 5 ; clock line (port_b) chpsel equ 4 ; chip select line (port_b) timeout equ 1 ; write cycle timeout warning (port_a) ; ;************************************************************* org 01ffh begin goto PWRUP ; set the reset vector org 000h goto PWRUP ; ;************************************************************* ; DATA POLL DELAY ROUTINE ; This routine delays 100 us is ; used for delay between polls ;************************************************************* dpdelay ; movlw .25 ; timing adjustment variable movwf loops2 top nop decfsz loops2 ; loops complete? goto top ; no, go again ; retlw 0 ; yes, return from sub ; 0000 0000 0A26 0000 0A26 0001 0002 0003 0004 0005 0C19 0036 0000 02F6 0A03 0006 0800 01FF 16c5x/7x Cross-Assembler V4.12 Released Line 0103 0104 0105 0106 0107 0108 0109 0110 0111 0112 0113 0114 0115 0116 0117 0118 0119 0120 0121 0122 0123 0124 PC Mon Jun 06 10:49:00 1994 Page 3 Opcode 0007 0008 0009 000A 04C6 0486 04A6 0000 000B 000C 000D 000E 0586 05C6 0000 05A6 000F 0010 0011 0012 0000 0000 04A6 0800 ;************************************************************** ; Start Bit Subroutine ; this routine generates a start bit ; (Chip select and DI high when clock goes high) ;**************************************************************; BSTART bcf port_b,datin ; set datain and chipselect lines bcf port_b,chpsel ; low just to check operation bcf port_b,sclk ; make sure clock starts low too. nop ; bsf port_b,chpsel ; set chip select line high bsf port_b,datin ; set data in line high nop bsf port_b,sclk ; set the clock line high to ; generate the start bit nop nop bcf port_b,sclk ; set clock low again retlw 0 ; ;************************************************************* DS00560D-page 12 © 1994 Microchip Technology Inc. 8-110 Using the 93LC56 and 93LC66 0125 0126 0127 0128 0129 0130 0131 0132 0133 0134 0135 0136 0137 0138 0139 0140 0141 0142 0143 0144 0145 0146 0147 0148 0149 0150 0151 0152 0153 0013 0014 0015 0016 07CA 0A17 05C6 0A18 0017 0018 0019 001A 001B 04C6 05A6 0000 04A6 0800 001C 001D 0212 0031 001E 001F 0020 04CA 06F0 05CA ; BITOUT routine ; This routine takes one bit of data in ‘do’ and ; transmits it to the serial EE device ;************************************************************* BITOUT btfss eeprom,do ; check state of data bit goto bitlow ; low, goto bitlow bsf port_b,datin ; high, set datain high goto clkout ; and clock it ; bitlow bcf port_b,datin ; output a logic low clkout bsf port_b,sclk ; set clock line high nop bcf port_b,sclk ; return clock line low retlw 0 ; ;**************************************************************** ; Transmit Data Subroutine ; This routine takes the byte of data stored in the ; ‘datao’ register and transmits it to the serial EE device. ;**************************************************************** TX movf bits,w ; set the number of bits to xmit movwf count ; TXLP bcf eeprom,do ; assume bit 7 is low btfsc txbuf,7 ; is bit 7 clear? bsf eeprom,do ; no, set data bit =1 16c5x/7x Cross-Assembler V4.12 Released Line PC Opcode 0154 0155 0156 0157 0158 0159 0160 0161 0162 0163 0164 0165 0166 0167 0168 0169 0170 0171 0172 0173 0174 0175 0176 0177 0178 0179 0180 0181 0182 0183 0184 0185 0186 0187 0188 0021 0022 0023 0024 0025 0913 0370 02F1 0A1E 0800 0026 0027 0028 0C00 0005 0065 0029 002A 0C80 0006 002B 0907 002C 002D 0C02 0032 call rlf decfsz goto retlw Mon Jun 06 10:49:00 1994 BITOUT txbuf count TXLP 0 ; ; ; ; ; Page 4 transmit 1 bit to serial EE rotate txbuf left all bits done? no, do another bit yes, jump out ; ;**************************************************************** ; POWER-UP ROUTINE ; This is the program entry point, which in this case simply ; sets the port_a I/O lines and directs control to the ; erase/write enable routine. ;***************************************************************** PWRUP ; movlw b’00000000' tris port_a ; set port_a as all output clrf port_a ; all lines low movlw tris b’10000000' port_b ; set RB7 as input, rest output; ; ; Fall through and do erase/write enable ; ;**************************************************************** ; EWEN (Erase/Write ENable Routine) ; this routine enables the dut for erasing and ; writing. This must be done prior to any erase,write ; eral,wral instructions. ;**************************************************************** EWEN ; call BSTART ; generate a start bit ; movlw .2 ; set # bits to 2 movwf bits ; © 1994 Microchip Technology Inc. DS00560D-page 13 8-111 8 Using the 93LC56 and 93LC66 0189 0190 0191 0192 0193 0194 0195 0196 0197 0198 0199 0200 0201 0202 0203 0204 002E 002F 0030 0031 0032 0033 0C00 0030 091C 0C08 0032 0CC0 movlw movwf call movlw movwf movlw b’00000000' txbuf TX .8 bits b’11000000' 0034 0035 0036 0037 0030 091C 0486 0000 movwf call bcf nop txbuf TX port_b,chpsel 0205 0206 0207 0208 0209 0210 0211 0212 0213 0214 0215 0216 0217 0218 0219 0220 0221 0222 0223 0224 0225 0226 0227 0228 0229 0230 0231 0232 0233 0234 0235 0236 0237 0238 0239 0240 0241 0242 0243 0244 0245 0246 0247 0248 0249 0250 0251 0252 get the opcode (00b) into the output buffer and transmit it set # bits to 8 get opcode and address (11XXXXXX) into output buffer and transmit it set chip select line low ; ; Now continue on to the write command ; ;************************************************************** ; WRITE 16c5x/7x Cross-Assembler V4.12 Released Line ; ; ; ; ; ; ; ; ; ; PC Mon Jun 06 10:49:00 1994 Page 5 Opcode 0038 0039 003A 003B 0C00 002C 0C08 0033 003C 0907 003D 003E 003F 0040 0041 0C02 0032 0C40 0030 091C 0042 0043 0044 0045 0046 0047 0048 0049 004A 004B 004C 0C08 0032 020C 0030 091C 0CAA 0030 091C 0C55 0030 091C 004D 0486 004E 004F 0000 0586 0050 0051 0052 0053 0054 0055 0CC8 0035 0901 06E6 0A59 02F5 ; This routine writes a AA55h pattern into ; 8 consecutive addresses starting at address 00. ; It will then ‘poll’ the data out line to determine ; when the write cycle is complete. If the cycle has ; not completed within 20 ms, then it will continue ; anyway and turn the timeout fail LED on. ; The write is done in the x16 mode: the user must ; have the ORG pin tied to Vcc on the device. This ; program will repeat forever. ;**************************************************************** WRITE ; movlw .0 ; set starting address to 00 movwf addr ; movlw .8 ; set number of bytes to write as 8 movwf bytcnt ; ; topwr call BSTART ; generate the start bit ; movlw .2 ; set # bits to 2 for the opcode movwf bits ; movlw b’01000000' ; get opcode (01b) movwf txbuf ; into the transmit buffer call TX ; and send it ; movlw .8 ; set # of bits to 8 for the movwf bits ; address movf addr,w ; get address counter movwf txbuf ; into output buffer call TX ; and send it movlw b’10101010' ; get first half of data (AAh) movwf txbuf ; into the transmit buffer call TX ; and send it movlw b’01010101' ; get second half of data (55h) movwf txbuf ; into transmit buffer call TX ; and send it ; bcf port_b,chpsel ; clear the chip select line ; to initiate write cycle nop bsf port_b,chpsel ; set the chip sel line high ; to begin data polling movlw .200 ; movwf loops ; poll 100 times before timeout(about 20ms) polltop call dpdelay ; wait 100us btfsc port_b,datout ; is the data out line high? goto okpoll ; yes-cycle complete: do another decfsz loops ; has it timed out? DS00560D-page 14 © 1994 Microchip Technology Inc. 8-112 Using the 93LC56 and 93LC66 0253 0254 0255 0056 0057 0058 0A52 0525 0A5A goto bsf goto polltop ; no, check again port_a,timeout; yes, set timeout LED and go on badpoll ; 16c5x/7x Cross-Assembler V4.12 Released Line 0256 0257 0258 0259 0260 0261 0262 0263 0264 0265 0266 0267 0268 0269 0270 0271 0272 0273 0274 0275 0276 0277 0278 0279 0280 0281 0282 0283 0284 0285 0286 0287 0288 0289 0290 0291 0292 0293 0294 PC Opcode 0059 005A 005B 005C 005D 0425 0486 02AC 02F3 0A3C 005E 0907 005F 0060 0061 0062 0063 0064 0065 0066 0C02 0032 0C00 0030 091C 0C08 0032 0C00 0067 0068 0069 006A 006B 0030 091C 0486 0000 0A2B 0000 okpoll badpoll bcf bcf incf decfsz goto Mon Jun 06 10:49:00 1994 port_a,timeout; port_b,chpsel ; addr ; bytcnt ; topwr ; ; Page 6 clear the timeout LED chip sel line back low increment address counter all bytes written? no, do another yes, go on ; ; Now continue on to the erase/write disable command ; ;**************************************************************** ; EWDS (Erase/Write Disable Routine) ; This routine executes the erase/write disable command ; which prevents the contents of the array from being ; written to. ; ;**************************************************************** EWDS ; call BSTART ; generate a start bit ; movlw .2 ; set # bits to 2 movwf bits ; movlw b’00000000' ; get the opcode (00b) movwf txbuf ; into the output buffer call TX ; and transmit it movlw .8 ; set # bits to 8 movwf bits ; movlw b’00000000' ; get opcode and address ; (00XXXXXX) movwf txbuf ; into output buffer call TX ; and transmit it bcf port_b,chpsel ; set chip select line low nop goto EWEN ; start all over ; ; END 8 © 1994 Microchip Technology Inc. DS00560D-page 15 8-113 Using the 93LC56 and 93LC66 16c5x/7x Cross-Assembler V4.12 Released Line PC 0001 0002 0003 0004 0005 0006 0007 0008 0009 0010 0011 0012 0013 0014 0015 0016 0017 0018 0019 0020 0021 0022 0023 0024 0025 0026 0027 0028 0029 0030 0031 0032 0033 0034 0035 0036 0037 0038 0039 0040 0041 0042 0043 0044 0045 0046 0047 0048 0049 0050 0051 LIST P=16C54,c=132 ;**************************************************************** ; 3-Wire Sequential Read Program (93 bytes) ; ; This program demonstrates how to interface a ; Microchip PIC16C54 to a 93LC56 or 93LC66 Serial EE ; device. This program will read 8 consecutive addresses ; in the ‘sequential read’ mode. This means that the opcode ; and address are sent for the first address only. After ; the first address is read, the Chip Select line is left ; high and clocks for the remaining 7 bytes are sent to the ; device. The device will automatically increment the address ; pointer in this mode, allowing the user to read as many ; consecutive addresses as needed. This program will repeat ; forever. ; ; This program communicates to the serial EE in the ; x16 mode, and ASSUMES THE USER HAS SET THE ORG PIN ; ON THE DEVICE TO Vcc. ; ; Timing is based on using the PIC16C54 in ‘XT’ mode ; using a 4MHz crystal. Clock speeds to the serial EE ; will be approximately 50 kHz for this setup. ; ; PIC16C54 to Serial EE Connections: ; ; PIC16C54 Serial EE ; —————— —————— ; Pin 10 (RB4) —> Chip Select ; Pin 11 (RB5) —> Clock ; Pin 12 (RB6) —> Data In ; Pin 13 (RB7) —> Data Out ; ORG = Vcc ; ;************************************************************ ; Register Assignments ;************************************************************ status equ 3h ; status register port_a equ 5h ; port 5 (port_a) port_b equ 6h ; port 6 (port b) used comm lines to serial EE eeprom equ 0ah ; bit buffer addr equ 0ch ; address register datai equ 0dh ; stored data input reg. datao equ 0eh ; stored data output reg. txbuf equ 10h ; transmit buffer count equ 11h ; bits transmitted so far bits equ 12h ; bits to transmit bytcnt equ 13h ; byte counter for read routine loops equ 15h ; delay loop counter loops2 equ 16h ; delay loop counter hbyte equ 17h ; high byte for input data 0003 0005 0006 000A 000C 000D 000E 0010 0011 0012 0013 0015 0016 0017 0052 0053 0054 0055 0056 0057 0058 0059 0060 PC Page 1 Opcode 16c5x/7x Cross-Assembler V4.12 Released Line Mon Jun 06 10:49:20 1994 Mon Jun 06 10:49:20 1994 Page 2 Opcode 0018 0007 0006 0007 0006 0005 lbyte equ 18h ; low byte for input data ;************************************************************ ; Bit Assignments ;************************************************************ di equ 7 ; eeprom input do equ 6 ; eeprom output datout equ 7 ; data out line (port_b) datin equ 6 ; data in line (port_b) sclk equ 5 ; clock line (port_b) DS00560D-page 16 © 1994 Microchip Technology Inc. 8-114 Using the 93LC56 and 93LC66 0061 0062 0063 0064 0065 0066 0067 0068 0069 0070 0071 0072 0073 0074 0075 0076 0077 0078 0079 0080 0081 0082 0083 0084 0085 0086 0087 0088 0089 0090 0091 0092 0093 0094 0095 0096 0097 0098 0099 0100 0101 0102 0004 0000 0000 0A40 0000 0A40 0001 0002 0003 0004 0005 0006 0007 0008 0009 000A 0C6E 0036 0000 0000 0000 0000 0000 0000 02F6 0A03 000B 000C 000D 02F5 0A01 0800 000E 000F 0010 0011 04C6 0486 04A6 0000 01FF chpsel equ 4 ; chip select line (port_b) ; ;************************************************************* org 01ffh begin goto PWRUP ; set the reset vector org 000h goto PWRUP ; ;************************************************************* ; DELAY ROUTINE ; This routine takes the value in ‘loops’ ; and multiplies it times 1 millisecond to ; determine delay time. ;************************************************************* WAIT ; top movlw .110 ; timing adjustment variable movwf loops2 top2 nop ; sit and wait nop nop nop nop nop decfsz loops2 ; inner loops complete? goto top2 ; no, go again ; decfsz loops ; outer loops complete? goto top ; no, go again retlw 0 ; yes, return from sub ; ;************************************************************** ; Start Bit Subroutine ; this routine generates a start bit ; (Chip select and DI high when clock goes high) ;************************************************************** BSTART bcf port_b,datin ; set datain and chipselect lines bcf port_b,chpsel ; low just to check operation bcf port_b,sclk ; make sure clock starts low too. nop ; 16c5x/7x Cross-Assembler V4.12 Released Line PC Opcode 0103 0104 0105 0106 0107 0108 0109 0110 0111 0112 0113 0114 0115 0116 0117 0118 0119 0120 0121 0122 0123 0124 0012 0013 0014 0015 0586 05C6 0000 05A6 0016 0017 0018 0019 0000 0000 04A6 0800 001A 001B 001C 001D 001E 001F 05EA 05A6 0000 07E6 04EA 04A6 bsf bsf nop bsf Mon Jun 06 10:49:20 1994 Page 3 port_b,chpsel port_b,datin ; set chip select line high ; set data in line high port_b,sclk ; set the clock line high to ; generate the start bit 8 nop nop bcf port_b,sclk ; set clock low again retlw 0 ; ;************************************************************** ; BITIN routine reads one bit of data from the ; serial EE device and stores it in ‘di’ ;************************************************************** BITIN bsf eeprom,di ; assume input bit is high bsf port_b,sclk ; set clock line high nop ; btfss port_b,datout ; read the data bit bcf eeprom,di ; input bit was low bcf port_b,sclk ; set clock line low ; © 1994 Microchip Technology Inc. DS00560D-page 17 8-115 Using the 93LC56 and 93LC66 0125 0126 0127 0128 0129 0130 0131 0132 0133 0134 0135 0136 0137 0138 0139 0140 0141 0142 0143 0144 0145 0146 0147 0148 0149 0150 0151 0152 0153 0020 0800 0021 0022 0023 0024 0025 0026 0027 0028 0029 002A 002B 002C 006D 0C08 0031 0403 036D 091A 040D 06EA 050D 02F1 0A25 0800 002D 002E 07CA 0A31 retlw 0 16c5x/7x Cross-Assembler V4.12 Released Line PC Opcode 0154 0155 0156 0157 0158 0159 0160 0161 0162 0163 0164 0165 0166 0167 0168 0169 0170 0171 0172 0173 0174 0175 0176 0177 0178 0179 0180 0181 0182 0183 0184 0185 0186 0187 0188 002F 0030 05C6 0A32 0031 0032 0033 0034 0035 04C6 05A6 0000 04A6 0800 0036 0037 0212 0031 0038 0039 003A 003B 003C 003D 003E 003F 04CA 06F0 05CA 092D 0370 02F1 0A38 0800 ; ;**************************************************************** ; Receive data routine ; This routine reads one byte of data from the part ; into the ‘datai’ register. ;**************************************************************** RX clrf datai ; clear input buffer movlw .8 ; set # bits to 8 movwf count bcf status,0 ; make sure carry bit is low RXLP rlf datai ; rotate the buffer left 1 bit call BITIN ; read 1 bit bcf datai,0 ; assume the input bit was low btfsc eeprom,di ; check the bit bsf datai,0 ; set high if necessary decfsz count ; 8 bits done? goto RXLP ; no, do another retlw 0 ; ;************************************************************* ; BITOUT routine ; This routine takes one bit of data in ‘do’ and ; transmits it to the serial EE device ;************************************************************* BITOUT btfss eeprom,do ; check state of data bit goto bitlow ; low, goto bitlow bitlow clkout Mon Jun 06 10:49:20 1994 bsf goto port_b,datin clkout bcf bsf nop bcf retlw port_b,datin port_b,sclk port_b,sclk 0 ; ; ; ; ; Page 4 high, set datain high and clock it output a logic low set clock line high ; return clock line low ; ;**************************************************************** ; Transmit Data Subroutine ; This routine takes the byte of data stored in the ; ‘datao’ register and transmits it to the serial EE device. ;**************************************************************** TX movf bits,w ; set the number of bits to xmit movwf count ; TXLP bcf eeprom,do ; assume bit 7 is low btfsc txbuf,7 ; is bit 7 clear? bsf eeprom,do ; no, set data bit =1 call BITOUT ; transmit 1 bit to serial EE rlf txbuf ; rotate txbuf left decfsz count ; all bits done? goto TXLP ; no, do another bit retlw 0 ; yes, jump out ; ;**************************************************************** ; POWER-UP ROUTINE ; This is the program entry point, which in this case simply ; sets the port_a I/O lines and directs control to the ; erase/write enable routine. ;***************************************************************** PWRUP DS00560D-page 18 © 1994 Microchip Technology Inc. 8-116 Using the 93LC56 and 93LC66 0189 0190 0191 0192 0193 0194 0195 0196 0197 0198 0199 0200 0201 0202 0203 0204 ; 0040 0041 0042 0043 0044 0C11 0005 0065 0C80 0006 movlw tris clrf movlw tris b’00010001' port_a port_a b’10000000' port_b ; set RB7 as input, rest output; ; ; Fall through and do the read ; ;********************************************************************* ; READ ROUTINE (Sequential read mode) ; This routine reads 8 consecutive addresses in ; sequential mode starting at address 0. This ; program will repeat forever ;********************************************************************* READ 16c5x/7x Cross-Assembler V4.12 Released Line 0205 0206 0207 0208 0209 0210 0211 0212 0213 0214 0215 0216 0217 0218 0219 0220 0221 0222 0223 0224 0225 0226 0227 0228 0229 0230 0231 0232 0233 0234 0235 0236 0237 ; set RA0 as input, rest output ; all lines low Mon Jun 06 10:49:20 1994 Page 5 PC Opcode 0045 0046 0047 0048 0C00 002C 0C08 0033 movlw movwf movlw movwf .0 addr .8 bytcnt 0049 004A 004B 004C 004D 004E 004F 0050 0051 0052 0053 090E 0C02 0032 0C80 0030 0936 0C08 0032 020C 0030 0936 call movlw movwf movlw movwf call movlw movwf movf movwf call BSTART .2 bits b’10000000' txbuf TX .8 bits addr,w txbuf TX ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; 0054 0055 0056 0921 020D 0037 call movf movwf RX datai,w hbyte ; read the high byte ; move input data to w ; xfer it to high byte 0057 0058 0059 0921 020D 0037 call movf movwf RX datai,w hbyte ; read the low byte ; move input data to w ; xfer it to low byte 005A 005B 005C 02AC 02F3 0A54 incf decfsz goto addr bytcnt rbyte ; add 1 to the address ; have all bytes been read? ; no, read another byte 005D 005E 0486 0A45 0000 bcf goto port_b,chpsel READ ; yes,clear the chip select line ; and start over ; rbyte set starting address to 00 set number of addresses to read as 8 generate the start bit set # bits to 2 get opcode (10b) into output buffer and transmit it set number of bits to 8 get the address into the output buffer and transmit it 8 END © 1994 Microchip Technology Inc. DS00560D-page 19 8-117 Using the 93LC56 and 93LC66 NOTES: DS00560D-page 20 © 1994 Microchip Technology Inc. 8-118 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. 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Albright Road Kokomo, Indiana 46902 Tel: 765-864-8360 Fax: 765-864-8387 Los Angeles 18201 Von 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 No. 71 Wusi Road Fuzhou 350001, China Tel: 86-591-7503506 Fax: 86-591-7503521 China - Shanghai 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 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 1 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. 3 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 0 Fax: 49-89-627-144-44 Italy Microchip Technology SRL Centro Direzionale Colleoni Palazzo Taurus 1 V. Le Colleoni 1 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.