TMP91C824
91C824-23
2008-02-20
Limitation point on the use of DFM
1. it’s prohibited to execute DFM enable/disable control in the SLOW mode (fs). 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 the commands that change the clock f
DFM
to f
OSCH
and stop the
DFM at the same time. Therefore the above execution 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.
4. More than 1 ms of interval time is required from stop of DFM to the next start up
of DFM.
Examples of settings are below.
(1) Start up control
(OK) Low-frequency oscillator operation mode (fs) (High-frequency oscillator STOP)
→
High-frequency oscillator start up
→
High-frequency oscillator operation mode
(f
OSCH
)
→
DFM start up
→
DFM use mode (f
DFM
)
LD
(SYSCR0), 11---1--B
;
High-frequency oscillator start up/warm-up start
WUP: BIT
2,
(SYSCR0)
;
JR
NZ,
WUP
;
Check for the flag of warm-up end
LD
(SYSCR1),
----0---B
;
Change the system clock fs to f
OSCH
LD
(DFMCR0), 01-0----B
;
DFM start up/lockup start
LUP: BIT
5,
(DFMCR0)
;
JR
NZ,
LUP
;
Check for the flag of lockup end
LD
(DFMCR0),
10-0----B
;
Change the system clock f
OSCH
to f
DFM
(OK) Low-frequency oscillator operation mode (fs) (High-frequency oscillator operate)
→
High-frequency oscillator operation mode (f
OSCH
)
→
DFM start up
→
DFM use
mode (f
DFM
)
LD
(SYSCR1),
----0---B
;
Change the system clock fs to f
OSCH
LD
(DFMCR0), 01-0----B
;
DFM start up/lockup start
LUP: BIT
5,
(DFMCR0)
;
JR
NZ,
LUP
;
Check for the flag of lockup end
LD
(DFMCR0),
10-0----B
;
Change the system clock f
OSCH
to f
DFM
(Error) Low-frequency oscillator operation mode (fs) (High-frequency oscillator STOP)
→
High-frequency oscillator start up
→
DFM start up
→
DFM use mode (f
DFM
)
LD
(SYSCR0), 11---1--B
;
High-frequency oscillator start up/warm-up start
WUP: BIT
2,
(SYSCR0)
;
JR
NZ,
WUP
;
Check for the flag of warm-up end
LD
(DFMCR0), 01-0----B
;
DFM start up/lockup start
LUP: BIT
5,
(DFMCR0)
;
JR
NZ,
LUP
;
Check for the flag of lockup end
LD
(DFMCR0),
10-0----B
;
Change the clock f
OSCH
to f
DFM
LD
(SYSCR1),
----0---B
;
Change the internal clock fs to f
DFM