UM10462
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User manual
Rev. 5.5 — 21 December 2016
338 of 523
NXP Semiconductors
UM10462
Chapter 15: LPC11U3x/2x/1x 16-bit counter/timers CT16B0/1
15.7.3 Timer Counter
The 16-bit Timer Counter is incremented when the Prescale Counter reaches its terminal
count. Unless it is reset before reaching its upper limit, the TC will count up to the value
0x0000 FFFF and then wrap back to the value 0x0000 0000. This event does not cause
an interrupt, but a Match register can be used to detect an overflow if needed.
15.7.4 Prescale Register
The 16-bit Prescale Register specifies the maximum value for the Prescale Counter.
15.7.5 Prescale Counter register
The 16-bit Prescale Counter controls division of PCLK by some constant value before it is
applied to the Timer Counter. This allows control of the relationship between the resolution
of the timer and the maximum time before the timer overflows. The Prescale Counter is
incremented on every PCLK. When it reaches the value stored in the Prescale Register,
the Timer Counter is incremented, and the Prescale Counter is reset on the next PCLK.
This causes the TC to increment on every PCLK when PR = 0, every 2 PCLKs when
PR = 1, ...
1
CRST
Counter reset.
0
0
Do nothing.
1
The Timer Counter and the Prescale Counter are
synchronously reset on the next positive edge of PCLK. The
counters remain reset until TCR[1] is returned to zero.
31:
2
-
Reserved, user software should not write ones to reserved bits.
The value read from a reserved bit is not defined.
NA
Table 299. Timer Control Register (TCR, address 0x4000 C004 (CT16B0) and 0x4001 0004
(CT16B1)) bit description
Bit
Symbol Value
Description
Reset
value
Table 300: Timer counter registers (TC, address 0x4000 C008 (CT16B0) and 0x4001 0008
(CT16B1)) bit description
Bit
Symbol
Description
Reset
value
15:0
TC
Timer counter value.
0
31:16
-
Reserved.
-
Table 301: Prescale registers (PR, address 0x4000 C00C (CT16B0) and 0x4001 000C
(CT16B1)) bit description
Bit
Symbol
Description
Reset
value
15:0
PCVAL
Prescale value.
0
31:16
-
Reserved.
-