Technical data

Analog Integrated Circuit Device Data
24 Freescale Semiconductor
908E621
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
908E621 ANALOG DIE MODES OF OPERATION
The 908E621 offers three operating modes: Normal (Run),
Stop, and Sleep. In Normal mode the device is active and is
operating under normal application conditions. The Stop and
Sleep modes are low power modes with wake-up capabilities.
The different modes can be selected by the STOP and
SLEEP bits in the System Control Register.
Figure 11
describes how transitions are done between the
different operating modes and Table
6, page 26, gives an
overview of the operating modes.
Figure 11. Operating Modes and Transitions
Normal Mode
This Mode is normal operating mode of the device, all
functions and power stages are active and can be enabled/
disabled. The voltage regulator provides the +5V V
DD
to the
MCU.
After a reset (e.g. Power On Reset, Wake-Up from Sleep)
the MCU has to set the PSON bit in the System Control
Register within 80ms typical (t
NORMREQ
), this is to ensure the
MCU has started up and is operating correctly. If the PSON
bit is not set within the required time frame the device is
entering SLEEP mode to reduce power consumption (fail
safe).
This MCU monitoring can be disabled e.g. for
programming by applying V
DD
on the TESTMODE terminal.
Stop Mode
In Stop mode the voltage regulator still supplies the MCU
with V
DD
(limited current capability). To enter the Stop mode
the STOP bit in the System Control Register has to be set
and the MCU has to be stopped also (see 908EY16
datasheet for details).
Wake-up from this mode is possible by LIN bus activity or
the wake-up input L0 and is maskable with the LINIE and/or
L0IE bits in the Interrupt Mask Register. The analog die is
generating an interrupt on
IRQ_A terminal to wake-up the
MCU. The wake-up / interrupt source can be evaluated with
the L0IF and LINIF bits in the Interrupt Flag Register.
RESET
Power
Down
Power Up
Normal
Request
V
DD
High and Reset Delay (t
RST
) expired
NORMAL
SLEEP
Wake-Up (Reset)
STOP
Reset (LVR, ext. Reset, (HTR))
SLEEP Command
STOP Command
Wake-Up Interrupt
PSON = 1
V
DD
Low
Reset (LVR, HTR, WDR, ext. Reset)
Reset (LVR, ext. Reset)
TESTMODE = 1
PSON = 0 and Normal Request
timeout (t
NORMREQ
) expired