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