GD32A50x User Manual
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5.
Reset and clock unit (RCU)
5.1.
Reset control unit (RCTL)
5.1.1.
Overview
GD32A50x
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.
5.1.2.
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 GD32A50x 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
®
-M33 application interrupt and reset control register
is set (SW_RSTn)
Option byte loader reset (OBL_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)
Low voltage detect reset (LVD_RSTn)
Loss-of-HXTAL reset (LOH_RSTn)
Loss-of-PLL reset (LOP_RSTn)
CPU lockup reset (LOCKUP_RSTn)