pc87591l National Semiconductor Corporation, pc87591l Datasheet - Page 143

• Manufacturer Part Number: pc87591l
• Description: Lpc Mobile Embedded Controllers
• Manufacturer: National Semiconductor Corporation

Revision 1.07
Embedded Controller Modules
Timer/Counter Register 2 (TnCNT2)
The TnCNT2 register is a word-wide read/write register that is not altered by reset. The power-up value is unknown.
Location: MFT16 1: 00 FD86
Type: R/W
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: R/W
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: R/W
Bit
Name
Reset
Bit
Name
Reset
Bit
Name
4-0
7-5
2-0
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
0 0 0:
0 0 1:
0 1 0:
0 1 1:
1 0 0:
Other:
MFT16 2: 00 FDA6
MFT16 2: 00 FDA8
MFT16 2: 00 FDAA
15
Description
No Clock (Counter 1 stopped)
Prescaled system clock
External Event on TBn
Pulse Accumulate
Slow-speed Clock
Reserved
7
0
7
0
14
Reserved
13
Reserved
16
16
16
16
16
16
6
0
6
0
12
11
(Continued)
5
0
5
0
10
9
C2CSEL
Description
Description
143
4
0
4
0
8
TCNT2
7
3
0
3
0
6
5
CLKPS
0
2
2
0
4
3
C1CSEL
1
0
1
0
2
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1
0
0
0
0
0