PIC18F24J10-E/ML MICROCHIP [Microchip Technology], PIC18F24J10-E/ML Datasheet - Page 37

• Manufacturer Part Number: PIC18F24J10-E/ML
• Description: 28/40/44-Pin High-Performance RISC Microcontrollers with nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

3.4.1
This mode is unique among the three low-power Idle
modes, in that it does not disable the primary device
clock. For timing-sensitive applications, this allows for
the fastest resumption of device operation with its more
accurate primary clock source, since the clock source
does not have to “warm up” or transition from another
oscillator.
PRI_IDLE mode is entered from PRI_RUN mode by
setting the IDLEN bit and executing a SLEEP instruc-
tion. If the device is in another Run mode, set IDLEN
first, then set the SCS bits to ‘10’ and execute SLEEP.
Although the CPU is disabled, the peripherals continue
to be clocked from the primary clock source specified
by the FOSC0 configuration bit. The OSTS bit remains
set (see Figure 3-6).
When a wake event occurs, the CPU is clocked from the
primary clock source. A delay of interval T
required between the wake event and when code
execution starts. This is required to allow the CPU to
become ready to execute instructions. After the
wake-up, the OSTS bit remains set. The IDLEN and
SCS bits are not affected by the wake-up (see
Figure 3-7).
FIGURE 3-6:
FIGURE 3-7:
© 2007 Microchip Technology Inc.
CPU Clock
Peripheral
Program
Counter
CPU Clock
Peripheral
OSC1
Program
Clock
Counter
OSC1
Clock
PRI_IDLE MODE
Q1
Q1
TRANSITION TIMING FOR ENTRY TO IDLE MODE
TRANSITION TIMING FOR WAKE FROM IDLE TO RUN MODE
Q2
Wake Event
PC
Q3
T
CSD
Q4
CSD
Preliminary
Q1
is
PIC18F45J10 FAMILY
PC
3.4.2
In SEC_IDLE mode, the CPU is disabled but the
peripherals continue to be clocked from the Timer1
oscillator. This mode is entered from SEC_RUN by set-
ting the IDLEN bit and executing a SLEEP instruction. If
the device is in another Run mode, set IDLEN first, then
set SCS1:SCS0 to ‘01’ and execute SLEEP. When the
clock source is switched to the Timer1 oscillator, the
primary oscillator is shut-down, the OSTS bit is cleared
and the T1RUN bit is set.
When a wake event occurs, the peripherals continue to
be clocked from the Timer1 oscillator. After an interval
of T
cuting code being clocked by the Timer1 oscillator. The
IDLEN and SCS bits are not affected by the wake-up;
the Timer1 oscillator continues to run (see Figure 3-7).
Note:
CSD
following the wake event, the CPU begins exe-
SEC_IDLE MODE
The Timer1 oscillator should already be
running prior to entering SEC_IDLE mode.
If the T1OSCEN bit is not set when the
SLEEP instruction is executed, the SLEEP
instruction will be ignored and entry to
SEC_IDLE mode will not occur. If the
Timer1 oscillator is enabled, but not yet
running, peripheral clocks will be delayed
until the oscillator has started. In such
situations, initial oscillator operation is far
from stable and unpredictable operation
may result.
PC + 2
Q2
Q3
DS39682C-page 35
Q4