Fan Control Device with Hardware Monitoring and Acoustic Noise Reduction Features
Datasheet
The PWM duty cycle is represented as follows:
Table 7.4 PWM Duty vs Register Reading
CURRENT DUTY
VALUE (DECIMAL)
VALUE (HEX)
0%
0
00h
25%
50%
64
40h
80h
FFh
128
255
100%
During spin-up, the PWM duty cycle is reported as 0%.
Notes:
■
The PWMx Current Duty Cycle always reflects the current duty cycle on the associated PWM pin.
■
The PWMx Current Duty Cycle register is implemented as two separate registers: a read-only and
a write-only. When a value is written to this register in manual mode there will be a delay before
the programmed value can be read back by software. The hardware updates the read-only PWMx
Current Duty Cycle register on the beginning of a PWM cycle. If Ramp Rate Control is disabled,
the delay to read back the programmed value will be from 0 seconds to 1/(PWM frequency)
seconds. Typically, the delay will be 1/(2*PWM frequency) seconds.
7.2.7
Register 3Eh: Company ID
Register
Address
Read/
Write
Bit 7
Bit 0
Default
Value
Register Name
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
(MSb)
(LSb)
3Eh
R
Company ID
7
6
5
4
3
2
1
0
5Ch
The Company ID register contains the company identification number. This number is a method for
uniquely identifying the part manufacturer.
This register is read only – a write to this register has no effect.
7.2.8
Register 3Fh: Version / Stepping
Register
Address
Read/
Write
Bit 7
Bit 0
Default
Value
Register Name
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
(MSb)
(LSb)
3Fh
R
Version / Stepping
VER3
VER
2
VER
1
VER
0
STP
3
STP
2
STP
1
STP0
65h
The four least significant bits of the Version / Stepping register [3:0] contain the current stepping of the
EMC6D102 silicon. The four most significant bits [7:4] reflect the version number.
The register is used by application software to identify which device has been implemented in the given
system. Based on this information, software can determine which registers to read from and write to.
Further, application software may use the current stepping to implement work-arounds for bugs found
in a specific silicon stepping. This register is read only – a write to this register has no effect.
Revision 0.4 (04-05-05)
SMSC EMC6D102
DATA5S2HEET
SMSC [ SMSC CORPORATION ]
