ISD91200 Series Technical Reference Manual
Release Date: Sep 16, 2019
- 416 -
Revision 2.4
Frequency Measurement Control Register (ANA_FQMMCTL)
Register
Offset
R/W
Description
Reset Value
ANA_FQMMCTL
0x94
R/W
Frequency Measurement Control Register
0x0000_0001
31
30
29
28
27
26
25
24
FQMMEN
Reserved
23
22
21
20
19
18
17
16
CYCLESEL
15
14
13
12
11
10
9
8
Reserved
7
6
5
4
3
2
1
0
Reserved
MMSTS
CLKSEL
Table 7-12 Frequency Measurement Control Register (ANA_FQMMCTL, address 0x4008_0094).
Bits
Description
[31]
FQMMEN
FQMMEN
0 = Disable/Reset block.
1 = Start Frequency Measurement.
[30:24]
Reserved
Reserved.
[23:16]
CYCLESEL
Frequency Measurement Cycles
Number of reference clock periods plus one to measure target clock (PCLK). For example if
reference clock is OSC32K (T is 30.5175us), set CYCLESEL to 7, then measurement period would
be 30.5175*(7+1), 244.1us.
[15:3]
Reserved
Reserved.
[2]
MMSTS
Measurement Done
0 = Measurement Ongoing.
1 = Measurement Complete.
[1:0]
CLKSEL
Reference Clock Source
00b: OSC10k,
01b: OSC32K (default),
1xb: I2S_WS – can be GPIOA[4,8,12] according to SYS_GPA_MFP register, configure I2S in SLAVE
mode to enable.