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7
Bit symbol
DFMCR0
ACT1
(00E8H)
Read/Write
R/W
After reset
0
Function
DFM LUP
00
STOP STOP f
01
RUN
10
RUN
11
RUN
Bit symbol
DFMCR1
D7
Read/Write
(00E9H)
R/W
After reset
0
Function
Limitation point on the use of DFM
1. It's prohibited to execute DFM enable/disable control in the SLOW mode (fs).
(Write to DFMCR0<ACT1:0> = "10").
You should control DFM in the NORMAL mode.
2. If you stop DFM operation during using DFM (DFMCR0<ACT1:0> = "10"), you
shouldn't execute that change the clock f
same time. Therefore the above execution should be separated into two procedures
as showing below.
LD
LD
3. If you stop high-frequency oscillator during using DFM (DFMCR0<ACT1:0> =
"10"), you should stop DFM before you stop high-frequency oscillator.
Please refer to 3.3.5 "Clock Doubler (DFM)" for the details.
6
5
ACT0
DLUPFG
R/W
R
0
0
select f
Lockup
FPH
status flag
OSCH
0: LUP end
RUN
f
OSCH
1: LUP not
STOP f
DFM
end
STOP f
OSCH
D6
D5
R/W
R/W
0
0
Input frequency 4 to 8.25 MHz (at 2.7 V to 3.6 V): write "0BH"
Input frequency 2 to 2.5 MHz (at 2.0 V ± 10%): write "1BH"
Figure 3.3.4 SFR for DFM
(DFMCR0), C0H
(DFMCR0), 00H
91C824-16
4
3
DLUPTM
R/W
0
Lockup time
12
0: 2
/f
OSCH
10
1: 2
/f
OSCH
D4
D3
R/W
R/W
1
0
DFM revision
to f
DFM
OSCH
;
Change the clock f
to f
DFM
;
DFM stop
TMP91C824
2
1
0
D2
D1
D0
R/W
R/W
R/W
0
1
1
and stop the DFM at the
OSCH
2008-02-20
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