Using the 93LC56 and 93LC66
16c5x/7x Cross-Assembler V4.12 Released
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PC
Opcode
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
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in the ‘random read’ mode. This means that the opcode
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and address for each byte will be sent to the device.
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This program will repeat forever.
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Another, more efficient method of reading consecutive
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addresses is called the ‘sequential read’ mode. This
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involves sending the opcode and address for the first
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byte to read, then continuing to provide clocks for the
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next addresses. The device will automatically increment
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the address. An example of the sequential read mode is
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provided in the ‘3wseqr.asm’ file.
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This program communicates to the serial EE in the
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x16 mode, and ASSUMES THE USER HAS SET THE ORG PIN
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ON THE DEVICE TO Vcc.
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Timing is based on using the PIC16C54 in ‘XT’ mode
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using a 4Mhz crystal. Clock speeds to the serial EE
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will be approximately 50 kHz for this setup.
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PIC16C54 to Serial EE Connections:
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PIC16C54
Serial EE
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——————
——————
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Pin 10 (RB4) —> Chip Select
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Pin 11 (RB5) —> Clock
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Pin 12 (RB6) —> Data In
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Pin 13 (RB7) —> Data Out
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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
Mon Jun 06 10:49:10 1994
Page 2
Mon Jun 06 10:49:10 1994
Page 1
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16c5x/7x Cross-Assembler V4.12 Released
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PC
Opcode
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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
MICROCHIP [ MICROCHIP TECHNOLOGY ]
