TMP91C824
91C824-13
2008-02-20
The clock operating modes are as follows: (a) Single clock mode (X1, X2 pins only), (b) Dual
clock mode (X1, X2, XT1 and XT2 pins) and (c) Triple clock mode (The X1, X2, XT1 and XT2
pins and DFM).
Figure 3.3.1 shows a transition figure.
Note 1: It’s prohiibited to control DFM in SLOW mode when shifting from SLOW mode to NORMAL mode
with use of DFM. (DFM start up/stop/change write to DFMCR0<ACT1:0> register)
Note 2: If you shift from NORMAL mode with use of DFM to NORMAL mode, the instructions should be
separated into two procedures as below. Change CPU clock
→
Stop DFM circuit.
Note 3: It’s prohibited to shift from NORMAL mode with use of DFM to STOP mode directly. You should
set NORMAL mode once, and then shift to STOP mode. (You should stop high-frequency
oscillator after you stop DFM.)
Figure 3.3.1 System Clock Block Diagram
Note: The clock frequency input from the X1 and X2 pins is called f
OSCH
and the clock frequency input
from the XT1 and XT2 pins is called fs. The clock frequency selected by SYSCR1<SYSCK> is
called the system clock f
FPH
. The system clock f
SYS
is defined as the divided clock of f
FPH
, and
one cycle of f
SYS
is called one state.
(c)
Triple clock mode trasision Figure
Using DMF
Instruction
Reset
(f
OSCH
/32)
Release reset
Instruction
Interrupt
STOP mode
(Stops all circuits)
NORMAL mode
(fOSCH/gear value/2)
IDLE2 mode
(I/O operate)
IDLE1 mode
(Operate only oscillator)
(a)
Single clock mode transition figure
(b)
Dual clock mode transition fiigure
STOP mode
(Stops all circuits)
SLOW mode
(fs/2)
Reset
(f
OSCH
/32)
Release reset
NORMAL
mode
(fOSCH/gear value/2)
IDLE2 mode
(I/O operate)
IDLE1 mode
(Operate only oscillator)
IDLE2 mode
(I/O operate)
IDLE1 mode
(Operate only oscillator)
Reset
(f
OSCH
/32)
Release reset
NORMAL
mode
(fOSCH/gear value/2)
IDLE2 mode
(I/O operate)
IDLE1 mode
(Operate only oscillator)
STOP mode
(Stops all circuits)
SLOW mode
(fs/2)
NORMAL mode
(4
×
fOSCH/gear
value/2)
IDLE2 mode
(I/O operate)
IDLE1 mode
(Operate oscillator and DFM)
IDLE2 mode
(I/O operate)
IDLE1 mode
(Operate only oscillator)
Instruction
Instruction
Interrupt
Interrupt
Instruction
Instruction
Interrupt
Interrupt
Instruction
Instruction
Interrupt
Interrupt
Instruction
Interrupt
Instruction
Instruction
Interrupt
Interrupt
Instruction
Instruction
Instruction
Interrupt
Note
(Note)
Instruction
Interrupt
Instruction
Interrupt
Instruction
Interrupt
Instruction