MCU Modes of Operation
MC1321x Reference Manual, Rev. 1.6
Freescale Semiconductor
10-5
If Stop3 is exited by means of the RESET pin, then the MCU will be reset and operation will resume after
taking the reset vector. Exit by means of an asynchronous interrupt or the real-time interrupt will result in
the MCU taking the appropriate interrupt vector.
A separate self-clocked source (
≈
1 kHz) for the real-time interrupt allows a wake up from Stop2 or Stop3
Mode with no external components. When RTIS2:RTIS1:RTIS0 = 0:0:0, the real-time interrupt function
and this 1-kHz source are disabled. Power consumption is lower when the 1-kHz source is disabled, but in
that case the real-time interrupt cannot wake the MCU from stop.
10.6.4
Active BDM Enabled in Stop Mode
Entry into the Active Background Mode from run mode is enabled if the ENBDM bit in BDCSCR is set.
This register is described in the
. If ENBDM is set when the CPU executes a
STOP instruction, the system clocks to the background debug logic remain active when the MCU enters
Stop Mode so background debug communication is still possible. In addition, the voltage regulator does
not enter its low-power standby state but maintains full internal regulation. If the user attempts to enter
either Stop1 or Stop2 with ENBDM set, the MCU will instead enter Stop3.
Most background commands are not available in Stop Mode. The memory-access-with-status commands
do not allow memory access, but they report an error indicating that the MCU is in either stop or Wait
Mode. The BACKGROUND command can be used to wake the MCU from stop and enter Active
Background Mode if the ENBDM bit is set. After the device enters background debug mode, all
background commands are available. The table below summarizes the behavior of the MCU in stop when
entry into the background debug mode is enabled.
10.6.5
LVD Enabled in Stop Mode
The LVD system is capable of generating either an interrupt or a reset when the supply voltage drops below
the LVD voltage. If the LVD is enabled in stop by setting the LVDE and the LVDSE bits in SPMSC1 when
the CPU executes a STOP instruction, then the voltage regulator remains active during Stop Mode. If the
user attempts to enter either Stop1 or Stop2 with the LVD enabled for stop (LVDSE = 1), the MCU will
instead enter Stop3. The table below summarizes the behavior of the MCU in stop when the LVD is
enabled.
Table 10-2. BDM Enabled Stop Mode Behavior
Mode
PDC
PPDC
CPU, Digital
Peripherals,
FLASH
RAM
ICG
ATD
Regulator
I/O Pins
RTI
Stop3
Don’t
care
Don’t
care
Standby
Standby
Active
Disabled
1
1
Either ATD Stop Mode or Power-Down Mode depending on the state of ATDPU.
Active
States held
Optionally on
Summary of Contents for freescale semiconductor MC13211
Page 40: ...MC1321x Pins and Connections MC1321x Reference Manual Rev 1 6 2 6 Freescale Semiconductor...
Page 166: ...Modem Modes of Operation MC1321x Reference Manual Rev 1 6 7 22 Freescale Semiconductor...
Page 172: ...Modem Interrupt Description MC1321x Reference Manual Rev 1 6 8 6 Freescale Semiconductor...
Page 186: ...MCU Modes of Operation MC1321x Reference Manual Rev 1 6 10 8 Freescale Semiconductor...
Page 208: ...MCU Memory MC1321x Reference Manual Rev 1 6 11 22 Freescale Semiconductor...
Page 244: ...MCU Parallel Input Output MC1321x Reference Manual Rev 1 6 13 20 Freescale Semiconductor...
Page 288: ...MCU Central Processor Unit CPU MC1321x Reference Manual Rev 1 6 15 20 Freescale Semiconductor...
Page 308: ...MCU Timer PWM TPM Module MC1321x Reference Manual Rev 1 6 17 16 Freescale Semiconductor...
Page 338: ...Inter Integrated Circuit IIC MC1321x Reference Manual Rev 1 6 19 14 Freescale Semiconductor...
Page 372: ...Development Support MC1321x Reference Manual Rev 1 6 21 20 Freescale Semiconductor...