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GD32L23x User Manual
82
4.
Reset and clock unit (RCU)
4.1.
Reset control unit (RCTL)
4.1.1.
Overview
GD32L23x
reset control includes the control of three kinds of reset: power reset, system reset
and backup domain reset. The power on reset, known as a cold reset, resets the full system
except the backup domain during a power up. A system reset resets the processor core and
peripheral IP components with the exception of the SW-DP controller and the backup domain.
A backup domain reset resets the backup domain. The resets can be triggered by an external
signal, internal events and the reset generators. More information about these resets will be
described in the following sections.
4.1.2.
Function overview
Power Reset
The power reset is generated by either an external reset as power on and power down reset
(POR/PDR reset), or by the internal reset generator when exiting standby mode. The power
reset sets all registers to their reset values except the backup domain. The power reset which
active signal is low will be de-asserted when the internal LDO voltage regulator is ready to
provide 1.1V power for GD32L23x
series. The RESET service routine vector is fixed at
address 0x0000_0004 in the memory map.
System Reset
A system reset is generated by the following events:
A power reset (POWER_RSTn)
A external pin reset (NRST)
A window watchdog timer reset (WWDGT_RSTn)
A free watchdog timer reset (FWDGT_RSTn)
The SYSRESETREQ bit in Cortex
®
-M23 Application Interrupt and Reset Control
Register is set (SW_RSTn)
Reset generated when entering Standby mode when resetting nRST_STDBY bit in
User Option Bytes (OB_STDBY_RSTn)
Reset generated when entering Deep-sleep mode when resetting nRST_DPSLP bit in
User Option Bytes (OB_DPSLP_RSTn)
A system reset resets the processor core and peripheral IP components except for the SW-
DP controller and the backup domain.
A system reset pulse generator guarantees low level pulse duration of 20 μs for each reset
source (external or internal reset).