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24LC128 (#602-00013)
General Description
The 24LC128 is a 128 Kb (16K X 8) I²C CMOS Serial EEPROM that can provide additional non-volatile data storage for the BASIC Stamp® 2 Modules. The 8-pin DIP package is easy to interface to the BS2, BS2e, BS2sx, BS2p24/40, BS2pe and BS2px24.
Features
• • • • • • • • •
Low-power CMOS technology
Maximum write current 3 mA at 5.5 V Maximum read current 400 µA at 5.5 V Standby current 100 nA typical at 5.5 V 5 mS max write cycle time 1,000,000 erase/write cycles
2-wire serial interface, I²C™ compatible 8-pin .300” DIP Package
Compatible with all BASIC Stamp 2 and SX Modules
Application Ideas
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Data storage Data tables
Quick Start Circuit
© Parallax, Inc. • 24LC128 (#602-00013) • 08/2005 v2.0 Page 1 of 5
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Connecting and Testing
Connect the 24LC128 as shown in the Quick Start Circuit, then use the appropriate demo program for your BASIC Stamp module to verify correct operation. If you are using an SX Microcontroller you will need to write or edit some existing I²C code to access the EEPROM.
Resources and Downloads
Check out the 24LC128 product page for example programs, articles and more:
http://www.parallax.com/detail.asp?product_id=602-00013
Device Information
Pin Definitions and Ratings
Pin Name 1 A0 2 A1 3 A2 4 Vss 5 SDA 6 SCL 7 WP 8 Vcc
Function
Address Pin 0
Address Pin 1 Address Pin 2 Ground -> 0 V Serial Data Input/Output Synchronous Clock Input Write-Protect Pin +5 V Power Input
Symbol Quantity Vcc Supply Voltage GND Ground Icc (sb)
Standyby Supply Current
Ir Read Current Iw Write Current
* Ratings from manufacturer datasheet
Minimum Typical Maximum Units 2.5 5.0 6.5 V 0 100 3
V nA
400 uA
mA
© Parallax, Inc. • 24LC128 (#602-00013) • 08/2005 v2.0 Page 2 of 5
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Communication Protocol
The 24LC128 communicates over the I²C bus with various types of transactions, such as Byte Write, Page Write, Random Read and Sequential Read.
All communication with the 24LC128 requires a control byte to be sent. This control byte includes a Start Bit, the Control Code (4 bits), the Chip Select (3 bits) and the R/W bit.
The address lines (A0, A1, A2) are used to select multiple 24LC128 devices on the same bus. Up to 8 24LC128 devices can be connected to the same bus.
Please see the manufacturer datasheet from Microchip for more information on reading/writing data to the 24LC128.
Source Code
BASIC Stamp® 2, 2e, 2sx Program
This program will allow you to use the 24LC128 with the BASIC Stamp 2, 2e and 2sx.
' ========================================================================= ' File....... 24LC128.bs2
' Purpose.... Interface To A 24LC128 16KB EEPROM ' Author..... Parallax, Inc.
' E-mail..... support@parallax.com ' Updated.... 08-09-2005 ' {$STAMP BS2} ' {$PBASIC 2.5}
' -----[ Program Description ]---------------------------------------------
' This code will interface the BS2, BS2e and BS2sx to a 24LC128 16KB EEPROM
' -----[ I/O Definitions ]-------------------------------------------------
SDA PIN 0 ' I2C Serial Data Line SCL PIN 1 ' I2C Serial Clock Line
' -----[ Constants ]-------------------------------------------------------
Address CON $A0 ' Address Of 24LC128 Ack CON 0 ' Acknowledge Bit
' -----[ Variables ]-------------------------------------------------------
temp VAR Byte ' Variable Used For Work i2cWork VAR Word ' Work Byte For I2C I/O i2cAck VAR Bit ' Ack Bit From Device eeprom_add VAR Word ' EEPROM Address
' -----[ Main Routine ]---------------------------------------------------- DO
DEBUG \"Enter value to store from 0 to 255: \"
© Parallax, Inc. • 24LC128 (#602-00013) • 08/2005 v2.0 Page 3 of 5
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DEBUGIN DEC3 temp
DEBUG CR, \"Enter address to store \ DEBUGIN DEC5 eeprom_add ' Writing Section GOSUB I2C_Stop GOSUB I2C_Start
GOSUB Control_Byte_Write GOSUB Addrs
GOSUB Write_Data GOSUB I2C_Stop PAUSE 100
' Reading Section GOSUB I2C_Start PAUSE 10
GOSUB Control_Byte_Write GOSUB Addrs
GOSUB I2C_Start
GOSUB Control_Byte_Read
SHIFTIN SDA, SCL, LSBFIRST, [i2cwork\\8] ' Send Byte To Device GOSUB I2C_Stop
DEBUG CR, \"Value stored at location \ \" is \LOOP
' -----[ Subroutines ]-----------------------------------------------------
I2C_Stop: ' I2C Stop Bit Sequence LOW SDA INPUT SCL
INPUT SDA ' SDA --> High While SCL High RETURN
I2C_Start: ' I2C Start Bit Sequence INPUT SDA INPUT SCL
LOW SDA ' SDA --> Low While SCL High RETURN
Addrs: ' I2C Address Byte Sequence i2cWork = eeprom_add
SHIFTOUT SDA, SCL, MSBFIRST, [i2cWork.HIGHBYTE\\8] ' Send Byte To Device SHIFTIN SDA, SCL, MSBPRE, [i2cAck\\1] ' Get Acknowledge Bit
SHIFTOUT SDA, SCL, MSBFIRST, [i2cWork.LOWBYTE\\8] ' Send Byte To Device SHIFTIN SDA, SCL, MSBPRE, [i2cAck\\1] ' Get Acknowledge Bit RETURN
Control_Byte_Write: ' I2C Control Write Byte Sequence i2cWork = Address
i2cWork.BIT0 = 0 ' Sets Unit To Write
SHIFTOUT SDA, SCL, MSBFIRST, [i2cWork\\8] ' Send Byte To Device SHIFTIN SDA, SCL, MSBPRE, [i2cAck\\1] ' Get Acknowledge Bit RETURN
Control_Byte_Read: ' I2C Control Read Byte Sequence i2cWork = Address
© Parallax, Inc. • 24LC128 (#602-00013) • 08/2005 v2.0 Page 4 of 5
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i2cWork.BIT0 = 1 ' Sets Device To Read
SHIFTOUT SDA, SCL, MSBFIRST, [i2cWork\\8] ' Send Byte To Device SHIFTIN SDA, SCL, MSBPRE, [i2cAck\\1] ' Get Acknowledge Bit RETURN
Write_Data: ' I2C Write Byte Sequence i2cWork = temp
SHIFTOUT SDA, SCL, MSBFIRST, [i2cWork\\8] 'Send Byte To Device SHIFTIN SDA, SCL, MSBPRE, [i2cAck\\1] ' Get Acknowledge Bit RETURN
BASIC Stamp® 2p, 2pe, 2px Program
This program will allow you to use the 24LC128 with the BASIC Stamp 2p, 2pe and 2px.
' ========================================================================= ' File....... 24LC128.bsp
' Purpose.... Interface To A 24LC128 16KB EEPROM ' Author..... Parallax, Inc.
' E-mail..... support@parallax.com ' Updated.... 08-09-2005 ' {$STAMP BS2p} ' {$PBASIC 2.5}
' -----[ Program Description ]---------------------------------------------
' This code will interface the BS2p, BS2pe and BS2px to a 24LC128 EEPROM
' -----[ I/O Definitions ]-------------------------------------------------
SDA PIN 0 ' I2C Serial Data Line SCL PIN 1 ' I2C Serial Clock Line
' -----[ Variables ]-------------------------------------------------------
value VAR Byte ' Variable Used To Store Value eeprom_add VAR Word ' EEPROM Address
' -----[ Main Routine ]---------------------------------------------------- DO
DEBUG \"Enter value to store from 0 to 255: \" DEBUGIN DEC3 Value
DEBUG CR, \"Enter address to store \ DEBUGIN DEC5 eeprom_add ' Writing Section
I2COUT SDA, $A0,eeprom_add.HIGHBYTE\\eeprom_add.LOWBYTE, [value]
PAUSE 20
' Reading Section
I2CIN SDA, $A1,eeprom_add.HIGHBYTE\\eeprom_add.LOWBYTE, [value] DEBUG CR, \"Value stored at location \ \" is \LOOP
© Parallax, Inc. • 24LC128 (#602-00013) • 08/2005 v2.0 Page 5 of 5
http://oneic.com/
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PARALLAX602-00013
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