ISD94100 Series Technical Reference Manual
Sep 9, 2019
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6.2 System Manager
6.2.1
Overview
System management includes the following sections:
System Reset
System Power Distribution
SRAM Memory Organization
System Timer (SysTick)
Nested Vectored Interrupt Controller (NVIC)
System Control register
6.2.2
System Reset
A system reset sets all registers to their reset values except some of the registers listed in Table
6.2.2-1, which will maintain their original values after reset.
A system reset can be triggered by one of the nine sources listed below. The reset source can be
identified by checking the reset flag bits in the System Reset Status Register (SYS_RSTSTS).
Hardware Reset Sources
-
Power-on Reset
-
Low level on the nRESET pin
-
Watchdog Time-out Reset and Window Watchdog Reset (WDT/WWDT Reset)
-
Low Voltage Reset (LVR)
-
Brown-out Detector Reset (BOD Reset)
-
CPU Lockup Reset
Software Reset Sources
-
CHIP Reset: writing 1 to CHIPRST (SYS_IPRST0[0]) will reset whole chip.
-
MCU Reset: writing 1 to SYSRESETREQ (AIRCR[2]) will reboot the device,
according to the boot selection defined in configuration byte CONFIG0.
-
CPU Reset: writing 1 to CPURST (SYS_IPRST0[1]) will reset Cortex
®
-M4 core
Only.
Low Voltage
Reset
Power-on
Reset
Brown-out
Reset
Reset Pulse Width
~3.2ms
WDT/WWDT
Reset
System Reset
~50k ohm
@3.3v
Reset Pulse Width
2 system clocks
nRESET
V
DD
CHIP Reset
CHIPRST(SYS_IPRST0[0])
CPU Reset
CPURST(SYS_IPRST0[1])
CPU Lockup
Reset
MCU Reset
SYSRSTREQ(AIRCR[2])
LVREN(SYS_BODCTL[7])
BODRSTEN(SYS_BODCTL[3])
POROFF(SYS_PORCTL[15:0])
Reset Pulse Width
64 WDT clocks
Reset Pulse Width
2 system clocks
Glitch Filter
66 us
Software Reset
