© 1994 Microchip Technology Inc.

DS00560D-page 9

Using the 93LC56 and 93LC66

8

0189

003B

0032

movwf

bits

;

0190

003C

0CC0

movlw

b’11000000'

; get opcode and address

0191

;

(11XXXXXX)

0192

003D

0030

movwf

txbuf

; into output buffer

0193

003E

0925

call

TX

; and transmit it

0194

003F

0486

bcf

port_b,chpsel

; set chip select line low

0195

0040

0000

nop

0196

;

0197

;

Now continue on to the write command

0198

;

0199

;**************************************************************

0200

;

Byte Write Routine

0201

;

This routine writes an AA55h pattern into

0202

;

8 consecutive addresses starting at address 00.

0203

;

A delay of about 10ms is given after each byte

0204

;

for the write cycle to complete.

16c5x/7x Cross-Assembler V4.12 Released

Mon Jun 06 10:49:06 1994

Page 5

Line

PC

Opcode

0205

;

The write is done in the x16 mode: the user must

0206

;

have the ORG pin tied to Vcc on the device

0207

;****************************************************************

0208

WRITE

0209

;

0210

0041

0C00

movlw

.0

; set starting address to 00

0211

0042

002C

movwf

addr

;

0212

0043

0C08

movlw

.8

; set number of bytes to write as 8

0213

0044

0033

movwf

bytcnt

;

0214

;

0215

0045

090E

topwr

call

BSTART

; generate the start bit

0216

;

0217

0046

0C02

movlw

.2

; set # bits to 2 for the opcode

0218

0047

0032

movwf

bits

;

0219

0048

0C40

movlw

b’01000000'

; get opcode (01b)

0220

0049

0030

movwf

txbuf

; into the transmit buffer

0221

004A

0925

call

TX

; and send it

0222

;

0223

004B

0C08

movlw

.8

; set # of bits to 8 for the

0224

004C

0032

movwf

bits

; address

0225

004D

020C

movf

addr,w

; get address counter

0226

004E

0030

movwf

txbuf

; into output buffer

0227

004F

0925

call

TX

; and send it

0228

0050

0CAA

movlw

b’10101010'

; get upper byte of data (AAh)

0229

0051

0030

movwf

txbuf

; into the transmit buffer

0230

0052

0925

call

TX

; and send it

0231

0053

0C55

movlw

b’01010101'

; get lower byte of data (55h)

0232

0054

0030

movwf

txbuf

; into transmit buffer

0233

0055

0925

call

TX

; and send it

0234

;

0235

0056

0486

bcf

port_b,chpsel ; clear the chip select line

0236

; to initiate write cycle

0237

;

0238

0057

0C0A

movlw

.10

;

0239

0058

0035

movwf

loops

; set delay time to 10mS

0240

0059

0901

call

WAIT

; and wait

0241

;

0242

005A

02AC

incf

addr

; increment address counter

0243

005B

02F3

decfsz

bytcnt

; all bytes written?

0244

005C

0A45

goto

topwr

; no, do another

0245

; yes, go on

0246

;

0247

;

Now continue on to the erase/write disable command

0248

;

0249

;****************************************************************

0250

;

EWDS (Erase/Write Disable Routine)

0251

;

This routine executes the erase/write disable command

0252

;

which prevents the contents of the array from being

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