MIC280_14 Datasheet, PDF (9/28 Pages) Micrel Semiconductor – Precision IttyBitty™ Thermal Supervisor

Micrel, Inc.
MIC280
Functional Description
Serial Port Operation
The MIC280 uses standard SMBus Write_Byte,
Read_Byte, and Read_Word 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
MIC280, 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. A
Read_Word is similar, but two successive data bytes are
clocked out rather than one. These protocols are shown
in Figure 1, Figure 2, and Figure 3.
The Command byte is eight bits (one byte) wide. This
byte carries the address of the MIC280 register to be
operated upon. The command byte values corresponding
to the various MIC280 registers are shown in Table 2.
Other command byte values are reserved, and should not
be used.
Slave Address
The MIC280 will only respond to its own unique slave
address. A match between the MIC280’s address and the
address specified in the serial bit stream must be made
to initiate communication. The MIC280’s slave address is
fixed at the time of manufacture. Eight different slave
addresses are available as determined by the part
number. See Table 1 below and the Ordering Information
table.
Table 1. MIC280 Slave Addresses
Part Number
Slave Address
MIC280-0YM6
100 1000b = 48h
MIC280-1YM6
100 1001b = 49h
MIC280-2YM6
100 1010b = 4Ah
MIC280-3YM6
100 1011b = 4Bh
MIC280-4YM6
100 1100b = 4Ch
MIC280-5YM6
100 1101b = 4Dh
MIC280-6YM6
100 1110b = 4Eh
MIC280-7YM6
100 1111b = 4Fh
Table 2. MIC280 Register Addresses
Target Register
Command Byte Value
Power-on
Default
Label
Description
Read
Write
TEMP0
Local temperature result
TEMP1h
Remote temperature result, high byte
STATUS
Status
CONFIG
Configuration
IMASK
Interrupt mask register
THIGH0
Local temperature high limit
TLOW0
Local temperature low limit
THIGH1h
Remote temperature high limit, high byte
TLOW1h
Remote temperature low limit, high byte
LOCK
Security register
TEMP1l
Remote temperature result, low byte
THIGH1l
Remote temperature high limit, low byte
TLOW1l
Remote temperature low limit, low byte
CRIT1
Remote overtemperature limit
CRIT0
Local overtemperature limit
MFG_ID
Manufacturer identification
DEV_ID
Device and revision identification
*The lower nibble contains the die revision level, e.g., Rev 0 = 00h.
00h
n/a
00h (0°C)
01h
n/a
00h (0°C)
02h
n/a
00h
03h
03h
80h
04h
04h
07h
05h
05h
3Ch (60°C)
06h
06h
00h (0°C)
07h
07h
50h (80°C)
08h
08h
00h (0°C)
09h
09h
00h
10h
n/a
00h
13h
13h
00h
14h
14h
00h
19h
19h
64h (100°C)
20h
20h
46h (70°C)
FEh
n/a
2Ah
FFh
n/a
0xh*
May 5, 2014
9
Revision 2.0