emc2104 Standard Microsystems Corp., emc2104 Datasheet - Page 19

• Manufacturer Part Number: emc2104
• Description: Emc2104 Dual Rpm-based Pwm Fan Controller With Hardware Thermal Shutdown
• Manufacturer: Standard Microsystems Corp.

Dual RPM-Based PWM Fan Controller with Hardware Thermal Shutdown
Datasheet
SMSC EMC2104
4.3
START
4.4
4.5
4.6
0 -> 1
START
START
START
0 -> 1
0 -> 1
0 -> 1
ADDRESS
0101_111
SLAVE
The Read Byte protocol is used to read one byte of data from the registers as shown in
The Send Byte protocol is used to set the internal address register pointer to the correct address
location. No data is transferred during the Send Byte protocol as shown in
The Receive Byte protocol is used to read data from a register when the internal register address
pointer is known to be at the right location (e.g. set via Send Byte). This is used for consecutive reads
of the same register as shown in
The ALERT# output can be used as a processor interrupt or as an SMBus Alert when configured to
operate as an interrupt.
When it detects that the ALERT# pin is asserted, the host will send the Alert Response Address (ARA)
to the general address of 0001_100xb. All devices with active interrupts will respond with their client
address as shown in
Read Byte
Send Byte
Receive Byte
Alert Response Address
RESPONSE
ADDRESS
ADDRESS
0101_111
0101_111
ADDRESS
WR
0001_100
0
SLAVE
SLAVE
ALERT
ACK
0
Table 4.6 Alert Response Address Protocol
Table
Register
Address
XXh
Table 4.5 Receive Byte Protocol
WR
4.6.
RD
Table 4.3 Read Byte Protocol
Table 4.4 Send Byte Protocol
0
1
RD
1
ACK
Table
0
DATASHEET
4.5.
START
0 -> 1
ACK
ACK
ACK
19
0
0
0
0101_111
Address
Slave
REGISTER DATA
REGISTER
ADDRESS
ADDRESS
0101_111
DEVICE
XXh
XXh
RD
1
ACK
0
Table
Register
NACK
NACK
ACK
Data
XXh
0
1
1
Revision 1.74 (05-08-08)
4.4.
NACK
Table
1
STOP
1 -> 0
STOP
1 -> 0
STOP
1 -> 0
4.3.
STOP
1 -> 0