Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK 데이터 시트
제품 코드
AT91SAM9N12-EK
194
SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]
11063K–ATARM–05-Nov-13
22.12.8 PMC Clock Generator Main Clock Frequency Register
Name:
CKGR_MCFR
Address:
0xFFFFFC24
Access:
Read-write
• MAINF: Main Clock Frequency
Gives the number of Main Clock cycles within 16 Slow Clock periods.
• MAINFRDY: Main Clock Ready
0: MAINF value is not valid or the Main Oscillator is disabled.
1: The Main Oscillator has been enabled previously and MAINF value is available.
Note:
To ensure reading a correct value on MAINF field, the MAINFRDY flag must be read at 1, then another read access
must be performed on the register to get a stable value on MAINF field.
must be performed on the register to get a stable value on MAINF field.
• RCMEAS: RC Measure
This bit is write-only.
0: No effect.
1: Restart a measure of the main RC frequency. MAINF will carry the new frequency as soon as a low to high transition occurs on
MAINFRDY flag.
MAINFRDY flag.
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
RCMEAS
–
–
–
MAINFRDY
15
14
13
12
11
10
9
8
MAINF
7
6
5
4
3
2
1
0
MAINF