pc87591l-n05 National Semiconductor Corporation, pc87591l-n05 Datasheet - Page 139

• Manufacturer Part Number: pc87591l-n05
• Description: Lpc Mobile Embedded Controller
• Manufacturer: National Semiconductor Corporation

Revision 1.2
4.0 Embedded Controller Modules
Clock Pre-Scaler Register (TnPRSC)
The TnPRSC register is a byte-wide read/write register. It contains the current value of the clock pre-scaler, CLKPS. The
register is cleared on reset. It defines the timer clock pre-scaler ratio.
Location: MFT16 1: 00 FD88
Type:
Clock Unit Control Register (TnCKC)
The TnCKC register is a byte-wide read/write register. It defines the clock source selection for each timer counter. The reg-
ister is cleared on reset, thus disabling timer/counter 1 and timer/counter 2 clocks.
Location: MFT16 1: 00 FD8A
Type:
Bit
Name
Reset
Bit
Name
Reset
4-0
7-5
2-0
5-3
7-6
Bit
Bit
CLKPS (Clock Pre-Scaler). The timer clock is generated by dividing the system clock by CLKPS+1. Therefore
the maximum timer clock frequency is equal to the system clock (CLKPS=00000) and the minimum timer clock
is the system clock divided by 32 (CLKPS=11111).
Reserved.
C1CSEL (Counter 1 Clock Select). Defines the clock mode for timer/counter 1 where:
Bits
2 1 0 Description
0 0 0: No Clock (Counter 1 stopped) (default)
0 0 1: Prescaled system clock
0 1 0: External Event on TBn
0 1 1: Pulse Accumulate
1 0 0: Slow-speed Clock
Other:
C2CSEL (Counter 2 Clock Select). Defines the clock mode for timer/counter 2.
Bits
5 4 3 Description
0 0 0: No Clock (Counter 2 stopped) (default)
0 0 1: Prescaled system clock
0 1 0: External Event on TBn
0 1 1: Pulse Accumulate
1 0 0: Slow-speed Clock
Other:
Reserved.
MFT16 2: 00 FDA8
R/W
MFT16 2: 00 FDAA
R/W
Reserved
7
0
7
0
Reserved
Reserved
Reserved
16
16
16
16
6
0
6
0
5
0
5
0
(Continued)
C2CSEL
Description
Description
139
4
0
4
0
3
0
3
0
CLKPS
2
0
2
0
C1CSEL
1
0
1
0
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0
0
0
0