EMC2300-AZC-TR SMSC, EMC2300-AZC-TR Datasheet - Page 52

• Manufacturer Part Number: EMC2300-AZC-TR
• Description: Industrial Temperature Sensors Auto Fan Contrllr Up to 4 Fans
• Manufacturer: SMSC

Specifications of EMC2300-AZC-TR

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Revision 0.32 (06-23-08)
CURRENT DUTY
on the algorithm described in the Auto Fan Control Operating Mode section and the Ramp Rate
Control logic, unless the associated fan is in manual mode – see below.
Note: When the device is configured for Manual Mode, the Ramp Rate Control logic should be
When read, the Current PWM Duty registers return the current PWM duty cycle for the respective
PWM signal.
These registers are read only – a write to these registers has no effect.
Note: If the current PWM duty cycle registers are written while the part is not in manual mode or
Manual Mode (Test Mode)
In manual mode, when the start bit is set to 1 and the lock bit is 0, the current duty cycle registers are
writable to control the PWMs.
Note: When the lock bit is set to 1, the current duty cycle registers are Read-Only.
The PWM duty cycle is represented as follows:
During spin-up, the PWM duty cycle is reported as 0%.
Notes:
100%
25%
50%
0%
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.
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.
disabled.
when the start bit is zero, the data will be stored in internal registers that will only be active
and observable when the start bit is set and the fan is configured for manual mode. While the
part is not in manual mode and the start bit is zero, the current PWM duty cycle registers will
read back FFh.
When a value is written to this register in manual mode there will be a delay before
Table 8.8 PWM Duty vs Register Reading
VALUE (DECIMAL)
DATASHEET
128
255
64
52
0
Fan Control Device with High Frequency PWM and Temperature Monitors
VALUE (HEX)
00h
40h
80h
FFh
SMSC EMC2300
Datasheet