DS28CM00 Maxim, DS28CM00 Datasheet - Page 8

• Manufacturer Part Number: DS28CM00
• Description: The DS28CM00 is a low-cost, electronic registration number to provide an absolutely unique identity that can be determined with the industry standard I²C and SMBus&#8482 interface
• Manufacturer: Maxim

I²C Communication⎯Legend
Command-Specific Communication⎯Color-Codes
Communication Examples
Write to Control Register (address 08)
Write to ROM Address (excludes address 08)
Write to invalid address (>08)
Read
Application Information
SDA and SCL Pullup Resistors
SDA is an open-drain output on the DS28CM00 that requires a pullup resistor (Figure 6) to realize high logic levels.
Because the DS28CM00 uses SCL only as input (no clock stretching) the master can drive SCL either through an
open-drain/collector output with a pullup resistor or a push-pull output.
Pullup Resistor R
According to the I²C specification, a slave device must be able to sink at least 3mA at a V
specification requires a current sink capability of 4mA at 0.4V. The DS28CM00 can sink at least 4mA at 0.4V V
over its entire operating voltage range. This DC characteristic determines the minimum value of the pullup resistor:
Rpmin = (V
is 1.2kΩ. The "Minimum RP" line in Figure 7 shows how the minimum pullup resistor changes with the operating
(pullup) voltage.
SYMBOL
Master-to-Slave
AD,0
AD,1
S
S
S
S
Sr
S
P
AD,0
AD,0
AD,0
AD,0
CC
- 0.4V)/4mA. With a maximum operating voltage of 5.25V, the minimum value for the pullup resistor
START Condition
Select DS28CM00 for Write Access
Select DS28CM00 for Read Access
Repeated START Condition
STOP Condition
P
Sizing
Slave-to-Master
A
A
A
A
DESCRIPTION
VMA
VMA
IMA
08h
Set address pointer
A\
A
A
A
<byte>
<byte>
address is not accepted
Sr
P
AD,1
8 of 9
A\
A
data is not accepted
SYMBOL
P
P
A
<byte>
VMA
IMA
A\
A
DS28CM00: I²C/SMBus Silicon Serial Number
<byte>
more bytes
one or
Acknowledged
Not Acknowledged
Transfer of One Byte
Valid Memory Address (00h to 08h)
Invalid Memory Address
A
<byte>
DESCRIPTION
last byte
OL
of 0.4V. The SMBus
A\
P
OL