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UM10850
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User manual
Rev. 2.4 — 13 September 2016
44 of 464
NXP Semiconductors
UM10850
Chapter 4: LPC5410x System configuration (SYSCON)
4.5.31 CLKOUT clock divider register
This register determines the divider value for the clock signal on the CLKOUT pin.
4.5.32 Frequency measure function control register
This register starts the frequency measurement function and stores the result in the
CAPVAL field. The target frequency can be calculated as follows with the frequencies
given in MHz:
F
target
= (CAPVAL - 2) x F
reference
/2
14
Select the target and reference frequencies using the
See
Section 4.2.3 “Measure the frequency of a clock signal”
,
Section 8.6.4 “Frequency measure function reference clock select
Section 8.6.5 “Frequency measure function target clock select register”
for
more on this function.
Table 59.
ADC clock source divider (ADCCLKDIV, address 0x4000 0108) bit description
Bit
Symbol
Description
Reset value
7:0
DIV
ADC clock divider value.
0: Disable ADC clock.
1: Divide by 1.
to
255: Divide by 255.
0
31:8
-
Reserved. Read value is undefined, only zero should be written. -
Table 60.
CLKOUT clock divider register (CLKOUTDIV, address 0x4000 010C) bit
description
Bit
Symbol
Description
Reset value
7:0
DIV
CLKOUT clock divider value.
0: Disable CLKOUT clock divider.
1: Divide by 1.
to
255: Divide by 255.
0
31:8
-
Reserved. Read value is undefined, only zero should be written. -
Table 61.
Frequency measure function control register (FREQMECTRL, address 0x4000 0120) bit description
Bit
Symbol
Description
Reset value
13:0
CAPVAL
Stores the capture result which is used to calculate the frequency of the target clock. This
field is read-only.
0
30:14
-
Reserved. Read value is undefined, only zero should be written.
-
31
PROG
Set this bit to one to initiate a frequency measurement cycle. Hardware clears this bit
when the measurement cycle has completed and there is valid capture data in the
CAPVAL field (bits 13:0).
0