M058SFAN Datasheet, PDF (37/72 Pages) List of Unclassifed Manufacturers – 32-bit Microcontroller

NuMicro M058S Series Datasheet
6.3.3 System Clock & SysTick Clock
The system clock has 4 clock sources which were generated from clock generator block. The
clock source switch depends on the register HCLK_S (CLKSEL0[2:0]). The block diagram is
shown below.
22.1184 MHz
HIRC
111
10 kHz LIRC
011
PLL FOUT
010
Reserved
001
4~24 MHz HXT
000
HCLK_S (CLKSEL0[2:0])
1/(HCLK_N+1)
HCLK_N (CLKDIV[3:0])
CPUCLK
HCLK
PCLK
CPU
AHB
APB
CPU in Power Down Mode
Legend:
HXT = 4~24 MHz external high speed crystal oscillator
HIRC = 22.1184 MHz internal high speed RC oscillator
LIRC = 10 kHz internal low speed RC oscillator
Figure 6.3-4 System Clock Block Diagram
The clock source of SysTick in Cortex-M0 core can use CPU clock or external clock
(SYST_CSR[2]). If using external clock, the SysTick clock (STCLK) has 4 clock sources. The
clock source switch depends on the setting of the register STCLK_S (CLKSEL0[5:3]. The block
diagram is shown below.
22.1184 MHz
HIRC
HCLK
4~24 MHz HXT
Reserved
4~24 MHz HXT
STCLK_S (CLKSEL0[5:3])
1/2
111
1/2
011
1/2
010
001
000
STCLK
Legend:
HXT = 4~24 MHz external high speed crystal oscillator
HIRC = 22.1184 MHz internal high speed RC oscillator
LIRC = 10 kHz internal low speed RC oscillator
Figure 6.3-5 SysTick clock Control Block Diagram
Nov. 27, 2014
Page 37 of 72
Rev.1.03