TMP91C824
91C824-15
3.3.2
SFR
7
6
5
4
3
2
1
0
bit Symbol
XEN
XTEN
RXEN
RXTEN
RSYSCK
WUEF
PRCK1
PRCK0
Read/Write
R/W
After reset
1
1
1
0
0
0
0
0
Function
High -frequen
cy oscillator
(fc)
0: Stop
1: Oscillation
Low-frequen
cy oscillator
(fs)
0: Stop
1: Oscillation
(note1)
High-frequen
cy oscillator
(fc) after
release of
Stop Mode
0: Stop
1: Oscillation
Low-frequen
cy oscillator
(fs) after
release of
Stop Mode
0: Stop
1: Oscillation
Selects clock
after release
of Stop
Mode
0: fc
1: fs
Warm-up
Timer
0: Write
Don’t care
1: Write
start timer
0: Read
end warm-up
1: Read
do not end
warm-up
Select prescaler clock
00: fFPH (note2)
01: reserved
10: fc/16
11: reserved
7
6
5
4
3
2
1
0
bit Symbol
SYSCK
GEAR2
GEAR1
GEAR0
Read/Write
R/W
After reset
0
1
0
0
Function
Select
system clock
0: fc
1: fs
Select gear value of high frequency (fc)
000: fc
001: fc/2
010: fc/4
011: fc/8
100: fc/16
101: ( reserved)
110: ( reserved)
111: ( reserved)
7
6
5
4
3
2
1
0
bit Symbol
SCOSEL
WUPTM1
WUPTM0
HALTM1
HALTM0
SELDRV
DRVE
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
After reset
0
1
0
1
1
0
0
Function
0: fs
1: f
SYS
Warm-Up Timer
00: reserved
01: 2
8
/inputted frequency
10:2
1 4
11:2
1 6
HALT mode
00: reserved
01: STOP mode
10: IDLE1 mode
11: IDLE2 mode
<DRVE>
mode
select
0: STOP
1: IDLE1
Pin state
control in
STOP/IDLE1
mode
0: I/O off
1: Remains
the state
before
HALT
SYSCR0
(00E0H)
SYSCR1
(00E1H)
SYSCR2
(00E2H)
(note1) By Reset, low-frequency oscillator is enable.
(note2) In case of using built-in SBI circuit, it must set SYSCR0<PRCK1:0> to ‘00’.
Figure 3.3.3 SFR for system clock