MIC281_14 Datasheet, PDF (7/14 Pages) Micrel Semiconductor – Low-Cost IttyBitty™ Thermal Sensor

Micrel, Inc.
MIC281
Functional Description
Serial Port Operation
The MIC281 uses standard SMBus Write_Byte and Read_Byte operations for communication with its host. The SMBus
Write_Byte operation involves sending the device’s slave address (with the R/W bit low to signal a write operation),
followed by a command byte and the data byte. The SMBus Read_Byte operation is a composite write and read
operation: the host first sends the device’s slave address followed by the command byte, as in a write operation. A new
start bit must then be sent to the MIC281, followed by a repeat of the slave address with the R/W bit (LSB) set to the high
(read) state. The data to be read from the part may then be clocked out. These protocols are shown in Figures 1 and 2.
The Command byte is eight bits (one byte) wide. This byte carries the address of the MIC281 register to be operated
upon. The command byte values corresponding to the various MIC281 registers are shown in Table 1. Other command
byte values are reserved, and should not be used.
Figure 1. Write_Byte Protocol
Figure 2. Read_Byte Protocol
Table 1. MIC281 Register Addresses
Target Register
Label
Description
TEMP
Remote temperature result
CONFIG
Configuration
MFG_ID
Manufacturer identification
DEV_ID
Device and revision identification
Note:
10. The lower nibble contains the die revision level (e.g., Rev. 0 = 00h).
Command Byte Value
Read
Write
01h
N/A
03h
03h
FEh
N/A
FFh
N/A
Power-on Default
00h (0°C)
80h
2Ah
0xh(10)
April 23, 2014
7
Revision 2.0