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NMI Configuration
273
SLAU356I – March 2015 – Revised June 2019
Copyright © 2015–2019, Texas Instruments Incorporated
System Controller (SYSCTL)
4.2.2.2
SRAM Bank Retention Configuration and Backup Memory
The application can optimize the leakage power consumption of the SRAM in LPM3 and LPM4 modes of
operation. To enable this, each SRAM bank can be individually configured for retention. Banks that are
enabled for retention retain their data through the LPM3 and LPM4 modes. The application can also retain
a subset of the enabled banks The Bank Retention Configuration for any bank have an effect only when
that bank is enabled using the SRAM Bank Enable Configuration is set.
For example, the application may need 32KB of SRAM for its processing needs (4 banks are kept
enabled). However, of these four banks, only one bank may contain critical data that must be retained in
LPM3 or LPM4, while the rest are powered off completely to minimize power consumption. See
SYS_SRAM_BANKRET register for details on how individual banks can be controlled by the application.
Bank0 of SRAM is always retained and cannot be powered down.
Therefore, it also operates up as a
possible backup memory in the LPM3, LPM4, and LPM3.5 modes of operation.
4.3
NMI Configuration
The following NMI sources are available on MSP432P4xx devices.
•
RSTn/NMI device pin in NMI configuration
•
Clock System (CS) sources
•
Power Supply System (PSS) sources
•
Power Control Manager (PCM) sources
See SYS_NMI_CTLSTAT register for configuration and status of different NMI sources available on the
device. These NMI sources can also be configured as maskable interrupts through appropriate
programming of the NVIC registers.
4.4
Watchdog Timer Reset Configuration
The watchdog timer module generates a reset upon password violation or timeout while in watchdog timer
mode of operation. It is possible to configure these watchdog timer module reset sources to hard reset or
soft reset independently through SYS_WDTRESET_CTL register.
4.5
Peripheral Halt Control
The Peripheral Halt Control (SYS_PERIHALT_CTL) register in the System Controller module allows the
user independent control over the functionality of device peripherals during code development and debug.
When the CPU is halted, the bits in this register can control whether the corresponding peripheral freezes
its operation (such as incrementing, transmit, and receive) or continues its operation (debug remains
nonintrusive). The registers of the peripheral remain accessible irrespective of the value programmed in
SYS_PERIHALT_CTL register.
4.6
Glitch Filtering on Digital I/Os
Some of the interrupt and wake-up capable digital I/Os can suppress glitches through the use of analog
glitch filter to prevent unintentional interrupt or wake-up during device operation. The analog filter
suppresses a minimum of 250-ns wide glitches. The glitch filter on these selected digital I/Os is enabled
by default. If the glitch filtering capability is not required in the application, it can be bypassed using the
SYS_DIO_GLTFLT_CTL register. When GLTFLT_EN bit in this register is cleared, the glitch filters on all
the digital I/Os are bypassed. The glitch filter is automatically bypassed on a digital I/O when it is
configured for peripheral or analog functionality by programming the respective PySEL0.x and PySEL1.x
registers.