SCH3112I-NE SMSC [SMSC Corporation], SCH3112I-NE Datasheet - Page 250

• Manufacturer Part Number: SCH3112I-NE
• Description: LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
• Manufacturer: SMSC [SMSC Corporation]

Rev 0.2 (09-28-04)
24.2.7
24.2.8
24.2.9
Register
Address
Register
Address
Register
Address
3Dh
3Eh
3Fh
CURRENT DUTY
/Write
/Write
/Write
Read
Read
Read
R
R
R
During spin-up, the PWM duty cycle is reported as 0%.
Notes:
■
■
Register 3Dh: Device ID
The Device ID register contains a unique value to allow software to identify which device has been
implemented in a given system.
Register 3Eh: Company ID
The company ID register contains a unique value to allow software to identify SMSC devices that been
implemented in a given system.
Register 3Fh: Revision
The Revision register contains the current version of this device.
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.
Register Name
Register Name
Register Name
Company ID
Device ID
Revision
When a value is written to this register in manual mode there will be a delay before
Table 24.4 PWM Duty vs Register Reading
VALUE (DECIMAL)
(MSb)
(MSb)
(MSb)
Bit 7
Bit 7
Bit 7
DATASHEET
7
7
7
LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
128
255
Bit 6
Bit 6
Bit 6
234
64
0
6
6
6
Bit 5
Bit 5
Bit 5
5
5
5
Bit 4
Bit 4
Bit 4
4
4
4
Bit 3
Bit 3
Bit 3
3
3
3
Bit 2
Bit 2
Bit 2
2
2
2
VALUE (HEX)
Bit 1
Bit 1
Bit 1
00h
40h
80h
FFh
1
1
1
SMSC SCH311X
(LSb)
(LSb)
(LSb)
Bit 0
Bit 0
Bit 0
0
0
0
Datasheet
Default
Default
Default
Value
Value
Value
8Ch
5Ch
00h