FXTH870xD
Sensors
12
Freescale Semiconductor, Inc.
3.5
STOP Modes
One of two stop modes are entered upon execution of a STOP instruction when the STOPE bit in the system option register is
set. In all STOP modes, all internal clocks are halted except for the low frequency 1 kHz oscillator (LFO) which runs continuously
whenever power is applied to the V
DD
and V
SS
pins. If the STOPE bit is not set when the CPU executes a STOP instruction, the
MCU will not enter any of the STOP modes and an illegal opcode reset is forced. The STOP modes are selected by setting the
appropriate bits in SPMSC2.
Table 1
summarizes the behavior of the MCU in each of the STOP1 and STOP4 modes. The STOP2
mode found in other Freescale S08 family members is not available; but the STOP3 mode is present like other members of the
Freescale S08 family members.
3.5.1
STOP1 Mode
The STOP1 mode provides the lowest possible standby power consumption by causing the internal circuitry of the MCU to be
powered down.
When the MCU is in STOP1 mode, all internal circuits that are powered from the voltage regulator are turned off. The voltage
regulator is in a low-power standby state. STOP1 is exited by asserting either a reset or an interrupt function to the MCU.
Entering STOP1 mode automatically asserts LVD. STOP1 cannot be exited until the V
DD
is greater than V
LVDH
or V
LV/DL
rising
(V
DD
must rise above the LVI re-arm voltage).
Upon wakeup from STOP1 mode, the MCU will start up as from a power-on reset (POR) by taking the reset vector.
NOTE
If there are any pending interrupts that have yet to be serviced then the device will not go
into the STOP1 mode. Be certain that all interrupt flags have been cleared before entry to
STOP1 mode.
3.5.2
STOP4 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 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 the STOP1 with the LVD enabled in STOP
(LVDSE = 1), the MCU will enter STOP4 instead.
Table 1. STOP Mode Behavior
Mode
STOP1
STOP4
LFO Oscillator, PWU
Always On & Clocking
Real-Time Interrupt (RTI)
(1)
Always On if using LFO as Clock
MFO Oscillator
(2)
Optionally On
Optionally On
HFO Oscillator
Off
Off
CPU
Off
Standby
RAM
Off
Standby
Parameter Registers
On
On
FLASH
Off
Standby
TPM1 2-Chan Timer/PWM
Off
Off
Digital I/O
Disabled
Standby
Sensor Measurement Interface (SMI)
Off
Optionally On
Pressure P-cell
Off
Optionally On
Optional Acceleration g-cell
Off
Optionally On
Temperature Sensor (in ADC10)
Off
Optionally On
(3)
Normal Temperature Restart
Optionally On
Optionally On
Voltage Reference (in ADC10)
Off
Optionally On
(3)
LFR Detector
(4)
Periodically On
Periodically On
LFR Decoder
Optionally On
Optionally On
RF Controller, Data Buffer, Encoder
Optionally On
Optionally On
RF Transmitter
(5)
Optionally On
Optionally On
ADC10
Off
Optionally On
(3)
Содержание FXTH870 D Series
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