UM10850
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User manual
Rev. 2.4 — 13 September 2016
180 of 464
NXP Semiconductors
UM10850
Chapter 13: LPC5410x SCTimer/PWM (SCT0)
Table 211. SCT control register (CTRL, address 0x5000 4004) bit description
Bit
Symbol
Value
Description
Reset
value
0
DOWN_L
-
This bit is 1 when the L or unified counter is counting down. Hardware sets this bit
when the counter is counting up, counter limit occurs, and BIDIR = 1.Hardware
clears this bit when the counter is counting down and a limit condition occurs or
when the counter reaches 0.
0
1
STOP_L
-
When this bit is 1 and HALT is 0, the L or unified counter does not run, but I/O events
related to the counter can occur. If a designated start event occurs, this bit is cleared
and counting resumes.
0
2
HALT_L
-
When this bit is 1, the L or unified counter does not run and no events can occur. A
reset sets this bit. When the HALT_L bit is one, the STOP_L bit is cleared. It is
possible to remove the halt condition while keeping the SCT in the stop condition
(not running) with a single write to this register to simultaneously clear the HALT bit
and set the STOP bit.
Remark:
Once set, only software can clear this bit to restore counter operation. This
bit is set on reset.
1
3
CLRCTR_L
-
Writing a 1 to this bit clears the L or unified counter. This bit always reads as 0.
0
4
BIDIR_L
L or unified counter direction select
0
0
Up. The counter counts up to a limit condition, then is cleared to zero.
1
Up-down. The counter counts up to a limit, then counts down to a limit condition or to
0.
12:5
PRE_L
-
Specifies the factor by which the SCT clock is prescaled to produce the L or unified
counter clock. The counter clock is clocked at the rate of the SCT clock divided by
PRE_L+1.
Remark:
Clear the counter (by writing a 1 to the CLRCTR bit) whenever changing
the PRE value.
0
15:13
-
Reserved
-
16
DOWN_H
-
This bit is 1 when the H counter is counting down. Hardware sets this bit when the
counter is counting, a counter limit condition occurs, and BIDIR is 1. Hardware
clears this bit when the counter is counting down and a limit condition occurs or
when the counter reaches 0.
0
17
STOP_H
-
When this bit is 1 and HALT is 0, the H counter does not, run but I/O events related
to the counter can occur. If such an event matches the mask in the Start register, this
bit is cleared and counting resumes.
0
18
HALT_H
-
When this bit is 1, the H counter does not run and no events can occur. A reset sets
this bit. When the HALT_H bit is one, the STOP_H bit is cleared.
It is possible to remove the halt condition while keeping the SCT in the stop
condition (not running) with a single write to this register to simultaneously clear the
HALT bit and set the STOP bit.
Remark:
Once set, this bit can only be cleared by software to restore counter
operation. This bit is set on reset.
1
19
CLRCTR_H
-
Writing a 1 to this bit clears the H counter. This bit always reads as 0.
0