AN560 Datasheet, PDF (1/22 Pages) Microchip Technology – Lowpower 3-wire non-volatile memories

Using the 93LC56 and 93LC66
AN560
Using the 93LC56 and 93LC66
INTRODUCTION
3-Wire Byte Write Program
The Microchip Technology Inc. 93LC56/66 are low-
power 3-wire non-volatile memories and are suitable for
many embedded system code and data storage applica-
tions. These devices are easily interfaced to most micro-
controllers 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 applica-
tion. 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
– 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
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)
This series of devices use a series of commands to
accomplish the normal memory functions. These are
3-Wire Sequential Read Program
READ, WRITE, EWEN, ERASE, ERAL, WRAL, EWDS.
– Delay Routine
For a more detailed discussion of the function of these
devices reference the appropriate data sheet and AN536,
also published by Microchip Technology.
– Start Bit Routine
– Bit In Routine
The following programs are included in this application
– Receive Data Routine
8
note and are fully functional stand-alone modules. They
– Bit Out Routine
are intended for use by those who are not already
familiar with interfacing a PIC16CXX microcontroller to
– Transmit Data Routine
a 93 series device. For those with more experience,
please refer to application note AN530.
– Power-up Routine
– Read Routine
3-Wire Byte Read Program
– Start Bit Routine
– Receive Data Routine
– Bit Out Routine
– Transmit Data Routine
– Power-up Routine
– Read Routine
Author:
Bruce Negley
Memory Products Division
© 1994 Microchip Technology Inc.
8-99
DS00560D-page 1