Software Description
KT912F634UG User’s Guide Rev. 2.0 10/2013
Freescale Semiconductor, Inc.
31
Archive Information
Archive Information
•
Lx wake-up - the device is awakened when the logical state of any enabled input L0-L5 is detected. The
state of the Lx inputs is checked continuously.
•
Cyclic sense wake-up - the same principle as the previous one, but the input Lx is sensed periodically. This
allows lower power consumption during the SLEEP or STOP mode. The Lx inputs are fed by periodic
switching of HS1 or HS2 switch with the corresponding detection of Lx state change.
Figure 27
shows the low power modes frame of the FreeMASTER control page.
Figure 27. Low Power Modes
The low power modes are entered by writing to the Mode Control Register (MCR) of the analog die. Anytime a
write to the MCR register is performed, communication over the BDM interface between the PC and the target
is terminated. The reason is that during wake-up, the device is transitioning from the reset to normal mode. The
BDM interface can interrupt this transition, so the device cannot wake-up properly. After the device completes
the wake-up sequence, the user must restore the BDM communication manually. The user must click twice on
the “Stop” icon, placed on the toolbar of the FreeMASTER application, as shown in
Figure 28
.
Figure 28. Re-enabling of the BDM Communication After Return from Low Power Modes
8.4
Embedded Software
8.4.1
Main Software Flow Chart
The main embedded software flow chart is shown in
Figure 29
. After the device and the application initialization,
the software runs in a continuous loop, checking the LIN communication (if enabled) and updating the analog
die registers, based on the FreeMASTER variables and watchdog servicing (if enabled). Other than this, only
one interrupt routine is implemented
(D2D_ISR)
, which handles the SCI receive interrupt routine used by the
LIN slave driver.
Action buttons for
entering low power modes
Forced wake-up option
Lx and cyclic sense
wake-up option
click
click
