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GD32F20x User Manual
81
A syste
m reset pulse generator guarantees low level pulse duration of 20 μs for each reset
source (external or internal reset).
Figure 5-1. The system reset circuit
Filter
WWDGT_RSTn
FWDGT_RSTn
SW_RSTn
OB_STDBY_RSTn
OB_DPSLP_RSTn
POWER_RSTn
NRST
System Reset
min 20 us
pulse generator
Backup domain reset
A backup domain reset is generated by setting the BKPRST bit in the Backup domain control
register or Backup domain power on reset (V
DD
or V
BAT
power on, if both supplies have
previously been powered off).
5.2.
Clock control unit (CCTL)
5.2.1.
Overview
The clock control unit provides a series of frequency clock functions. These include a Internal
8M RC oscillator (IRC8M), a High Speed crystal oscillator (HXTAL), a Low Speed Internal
40K RC oscillator (IRC40K), a Low Speed crystal oscillator (LXTAL), three Phase Lock Loop
(PLL,PLL1 and PLL2), a HXTAL clock monitor, clock prescalers, clock multiplexers and clock
gating circuitry.
The clocks of the AHB, APB and Cortex™-M3 are derived from the system clock (CK_SYS)
the clock source of the system clock can choose IRC8M, HXTAL or PLL. The maximum
operating frequency of the system clock (CK_SYS) can be up to 120 MHz. The Free
Watchdog Timer has independent clock source (IRC40K), and Real Time Clock (RTC) uses
the IRC40K, LXTAL or HXTAL/128 as its clock source.
Содержание GD32F20 Series
Страница 1: ...GigaDevice Semiconductor Inc GD32F20x ARM Cortex M3 32 bit MCU User Manual Revision 2 2 Oct 2019 ...
Страница 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Страница 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Страница 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
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Страница 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...