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Symbol
Name
Address
DFM
Control
E8H
DFMCR0
Register 0
DFM
Control
E9H
DFMCR1
Register 1
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
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.
Figure 3.3.4 SFR for DFM
7
6
ACT1
ACT0
DLUPFG
R/W
R/W
0
0
select f FPH
DFM
LUP
Lock up
Status Flag
f OSCH
00
STOP
STOP
0: end
f OSCH
01
RUN
RUN
1: not end
f DFM
10
RUN
STOP
f OSCH
11
RUN
STOP
R/W
R/W
0
0
Input frequency 4~6.75MHz(@2.7V~3.6V) : write "0BH"
Input frequency 2~2.5MHz(@2.0±10%) : write "1BH"
to f
and stop the DFM at the same time. Therefore the above executions should be
DFM
OSCH
(DFMCR0),C0H
; change the clock f
(DFMCR0),00H
; DFM stop
91C824-16
5
4
3
DLUPTM
R
R/W
0
0
Lock-up Time
12
0: 2
/ f OSCH
10
1: 2
/ f OSCH
R/W
R/W
R/W
0
1
0
DFM revision
to f
DFM
OSCH
TMP91C824
2
1
0
R/W
R/W
R/W
0
1
1
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