Chapter 3 Modes of Operation
MC9S08LG32 MCU Series, Rev. 5
44
Freescale Semiconductor
NOTE
When PTC6/RESET or PTF2/IRQ is used as an active low wakeup source
it must be configured as an input prior to executing a STOP instruction.
PTC6/RESET and PTF2/IRQ can be disabled as a wakeup if it is configured
as output port. For lowest power consumption in stop2, these pins must not
be left open if configured as input (enable the internal pullup or tie an
external pullup device).
Upon wakeup from stop2 mode, the MCU starts up as from a POR with the following sequence:
•
All module control and status registers are reset, except for SPMSC1-SPMSC2, RTCSC,
RTCCNT, RTCMOD, LCDPENx, LCDBPENx, and LCDWFRx.
•
The LVD reset function is enabled and the MCU remains in the reset state if V
DD
is below the LVD
trip point.
•
The CPU takes the reset vector
In addition to the above, upon waking up from stop2 mode, the PPDF bit in SPMSC2 is set. This flag is
used to direct user code to go to a stop2 recovery routine. PPDF remains set and the I/O pin states remain
latched until a 1 is written to PPDACK in SPMSC2.
If using the low-power oscillator during stop2 mode, you reconfigure the ICSC2 register that contains
oscillator control bits before PPDACK is written.
To maintain I/O states for pins that were configured as GPIO before entering stop2, you restore the
contents of the I/O port registers to the port registers before writing to the PPDACK bit. If the port registers
are not restored from RAM before writing to PPDACK, then the pins are switched to their reset states when
PPDACK is written.
For pins that were configured as peripheral I/O, you reconfigure the peripheral module that interfaces to
the pin before writing to the PPDACK bit. If the peripheral module is not enabled before writing to
PPDACK, the pins are controlled by their associated port control registers when the I/O latches are opened.
If enabled, LCD functionality continues in stop2 mode and upon stop2 recovery the LCD control registers
(LCDC0, LCDC1, LCDSUPPLY, LCDRVC, LCDBCTL, and LCDS) must be re-initialized before writing
the PPDACK.
3.6.2
Stop3 Mode
To enter stop3 mode, execute a STOP instruction under the conditions shown in
. The states of
all the internal registers and logic, RAM contents, and I/O pin states are maintained.
Stop3 mode can be exited by asserting RESET, or by an interrupt from one of the following sources: LVW,
RTC, ADC, IRQ, SCI1, SCI2, LCD, or KBI.
If stop3 is exited by means of the RESET pin, the MCU is reset and operation resumes after taking the
reset vector. Using an internal interrupt sources to exit, results in the MCU taking an appropriate interrupt
vector.
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Страница 26: ...Chapter 1 Device Overview MC9S08LG32 MCU Series Rev 5 26 Freescale Semiconductor...
Страница 40: ...Chapter 2 Pins and Connections MC9S08LG32 MCU Series Rev 5 40 Freescale Semiconductor...
Страница 96: ...Chapter 5 Resets Interrupts and General System Control MC9S08LG32 MCU Series Rev 5 96 Freescale Semiconductor...
Страница 296: ...Chapter 12 Serial Peripheral Interface S08SPIV4 MC9S08LG32 MCU Series Rev 5 296 Freescale Semiconductor...
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