UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
833 of 1269
NXP Semiconductors
UM10503
Chapter 28: LPC43xx State Configurable Timer (SCT)
When the UNIFY bit is 0, each event is associated with a particular counter by the
HEVENT bit in its event control register. An event cannot occur when its related counter is
halted nor when the current state is not enabled to cause the event as specified in its
event mask register. An event is permanently disabled when its event state mask register
contains all 0s.
An enabled event can be programmed to occur based on a selected input or output edge
or level and/or based on its counter value matching a selected match register.
Each event can modify its counter STATE value. If more than one event associated with
the same counter occurs in a given clock cycle, only the state change specified for the
highest-numbered event among them takes place. Other actions dictated by any
simultaneously occurring events all take place.
Table 671. SCT event control register 0 to 15 (EVCTRL - address 0x4000 0304 (EVCTRL0) to 0x4000 037C
(EVCTRL15)) bit description
Bit
Symbol
Value Description
Reset
value
3:0
MATCHSEL
-
Selects the Match register associated with this event (if any). A match can occur only
when the counter selected by the HEVENT bit is running.
0
4
HEVENT
Select L/H counter. Do not set this bit if UNIFY = 1.
0
0
Selects the L state and the L match register selected by MATCHSEL.
1
Selects the H state and the H match register selected by MATCHSEL.
5
OUTSEL
Input/output select
0
0
Selects the input selected by IOSEL.
1
Selects the output selected by IOSEL.
9:6
IOSEL
-
Selects the input or output signal associated with this event (if any). Do not select an
input in this register, if CKMODE is 1x. In this case the clock input is an implicit
ingredient of every event.
0
11:10 IOCOND
Selects the I/O condition for event n. (The detection of edges on outputs lag the
conditions that switch the outputs by one SCT clock). In order to guarantee proper
edge/state detection, an input must have a minimum pulse width of at least one SCT
clock period .
0
0x0
LOW
0x1
Rise
0x2
Fall
0x3
HIGH
13:12 COMBMODE
Selects how the specified match and I/O condition are used and combined.
0
0x0
OR. The event occurs when either the specified match or I/O condition occurs.
0x1
MATCH. Uses the specified match only.
0x2
IO. Uses the specified I/O condition only.
0x3
AND. The event occurs when the specified match and I/O condition occur
simultaneously.