EMC6D103S-CZC-TR SMSC, EMC6D103S-CZC-TR Datasheet - Page 43

• Manufacturer Part Number: EMC6D103S-CZC-TR
• Description: Industrial Temperature Sensors Auto Fan Contrllr Up to 4 Fans
• Manufacturer: SMSC

Specifications of EMC6D103S-CZC-TR

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

Fan Control Device with High Frequency PWM Support and Hardware Monitoring Features
Datasheet
SMSC EMC6D103
7.1.4.4.3
7.1.4.5
Internal PWM
Window for
Valid Tach
Tach
Pulses
Tach
Pulses
Pulses
Signal
The Tachometer circuit begins monitoring the tach when the associated PWM output transitions high
and the guard time has expired. Each tach circuit will continue monitoring until either the stretch time
ends or the programmed number of edges has been detected, whichever comes first. The associated
PWM output will continue to stretch until all tachs that are associated with it have taken a
measurement.
The Fan Tachometer value may be updated every 300ms, 500ms, or 1000ms.
FAN TACHOMETER OPTIONS FOR MODE 2
Fan Tachometer Reading Registers:
The Tachometer Reading registers are 16 bits , unsigned. When one byte of a 16-bit register is read, the
other byte latches the current value until it is read, in order to ensure a valid reading. The order is LSB first,
MSB second. The value FFFFh indicates that the fan is not spinning, or the tachometer input is not
connected to a valid signal (this could be triggered by a counter overflow). These registers are read
only – a write to these registers has no effect.
Notes:
2, 3, 5 or 9 “edges” to calculate the fan speed
Guard time A is programmable (8-63 clocks) to account for delays in the system
PWM Stretching options: 50, 100, 200, 400, 600, 800msec, and 950msec.
The PWM frequencies for modes 1 & 2 are: 11.0 Hz, 14.6 Hz, 21.9 Hz, 29.3 Hz, 35.2 Hz, 44.0 Hz,
58.6 Hz, 87.7Hz and 25Khz
Option to ignore first 3 tachometer edges after guard time
Option to force tach reading register to FFFEh to indicate a slow fan.
The Fan Tachometer Reading registers always return an accurate fan tachometer measurement,
even when a fan is disabled or non-functional.
FFFFh indicates that the fan is not spinning, or the tachometer input is not connected to a valid
signal (This could be triggered by a counter overflow).
1
A
B
2
Guard time A
Figure 7.5 PWM and Tachometer Concept
C
3
DATASHEET
PWM “ON”
43
D
4
(Figure
7.5)
E
5
F
6
Revision 0.3 (03-01-07)
(Figure
7.5)