PXS20RM Datasheet, PDF (238/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Clock Monitor Unit (CMU)
The memory map of each CMU is shown in Table 12-3.
Table 12-3. CMU memory map
Address offset
Register
0x00
0x04
0x08
0x0C
0x10
0x14
0x18
Control status register (CMU_CSR)
Frequency display register (CMU_FDISP)
High-frequency reference register A (CMU_HFREFR_A)
Low-frequency reference register A (CMU_LFREFR_A)
Interrupt status register (CMU_ISR)
Reserved
Measurement duration register (CMU_MDR)
Location
on page 12-2
on page 12-3
on page 12-4
on page 12-4
on page 12-5
on page 12-6
12.3.1 Control status register (CMU_CSR)
Address: Base + 0x00
Access: User read/write
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R0 0 0 0 0 0 0 0
0000000
SFM
W
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
R0 0
W
000
0
0
CKSEL1
0
0
0
0
RCDIV
CME
_A
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0
Figure 12-1. Control status register (CMU_CSR)
Table 12-4. CMU_CSR field descriptions
Field
Description
SFM
Start frequency measure
Set this bit to start a clock frequency measure. The bit is cleared by hardware when the measure is
ready in the CMU_FDR register. Software cannot clear this bit.
0 Frequency measurement is completed or not yet started.
1 Frequency measurement is not completed.
CKSEL1
Clock selection
This fieldselects the clock to be measured by the frequency meter.
For cut1 :
00 IRCOSC_CLK is selected.
01 IRCOSC_CLK is selected.
10 No clock is selected.
11 IRCOSC_CLK is selected.
For cut2/3:
00 IRCOSC_CLK is selected.
01 IRCOSC_CLK is selected.
10 IRCOSC_CLK is selected.
11 IRCOSC_CLK is selected.
12-2
PXS20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor