M-Boot ROM Description
553
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
ROM Code and Peripheral Booting
6.5.13 M-Boot ROM Reset Cause Handling
As shown in
, M-Boot ROM will be executed for any reset cause that resets the master
subsystem CPU core.
gives details on how M-Boot ROM handles each reset.
Table 6-9. M-Boot ROM Reset Cause Handling
Reset Source
M-Boot ROM action
POR
ModeZero-initialize all master subsystem memories, CLOCK_INIT(s) and follow normal
boot-up procedure
XRS Input
Zero-initialize M-Boot ROM stack memory, CLOCK_INIT(s) and follow normal boot-up
procedure
M3 WDT0 reset
Zero-initialize M-Boot ROM stack memory, CLOCK_INIT(s) and follow normal boot-up
procedure
M3 WDT1 reset
Zero-initialize M-Boot ROM stack memory, CLOCK_INIT(s) and follow normal boot-up
procedure
M3 NMIWD reset (M3 NMIRS)
Zero-initialize M-Boot ROM stack memory, CLOCK_INIT(s) and follow normal boot-up
procedure
M3 Software reset / debugger reset
Zero-initialize M-Boot ROM stack memory and follow normal boot-up procedure. Note
that clock settings are not modified here.
CLOCK_INIT(s) in the above table means SYSDIVSEL and M3SSDIVSEL dividers are configured for
divide by 1 operation, as explained in
above.
6.5.14 M-Boot ROM Exceptions Handling
shows how M-Boot ROM handles different possible exceptions that can occur during boot.
Table 6-10. M-Boot ROM Exceptions Handling
Exception Source
Description
M-Boot ROM Action
CLOCKFAIL
CLKFAIL condition detected
Clear MNMI Flags and log the error in
boot status location and continue to boot.
MCLKSTS.MCLKFLG is not cleared here.
M3BISTERR
BIST error on M3
Clear NMI Flags and log the error in boot
status location and continue to boot.
C28BISTERR
BIST error on C28X
Clear NMI Flags and log the error in boot
status location and continue to boot.
EXTGPIO
External GPIO NMI
Clear MNMI Flags and log the error in
boot status location and continue to boot.
C28PIENMIERR
NMI vector fetch mismatch on the control
subsystem
Clear MNMI Flags and log the error in
boot status location and continue to boot.
C28NMIWDRST
The control subsystem is reset by
CNMIWD timer
Clear MNMI Flags and log the error in
boot status location and continue to boot.
ACIBERR
ACIB access error
Clear MNMI Flags and log the error in
boot status location and continue to boot.
Bus Fault/ Memory Management Fault/
Usage Fault
Triggers HARD FAULT exception to NVIC
Log the error in boot status and configure
WDT0 and loop and let device reset on
WDT0 timeout
Hard Fault
Triggers HARD FAULT exception to NVIC
Log the error in boot status and configure
WDT0 and loop and let device reset on
WDT0 timeout
Spurious/un supported NVIC interrupt
Triggered because of any errors
Log the error in boot status and configure
WDT0 and loop and let device reset on
WDT0 timeout.