M054LAN Datasheet, PDF (30/64 Pages) Nuvotem Talema – ARM Cortex™-M0 32-BIT MICROCONTROLLER

M052/M054 Data Sheet
Clock Generator
„ Internal 10 kHz oscillator clock
„ Peripherals Clock (When these IP adopt 10 kHz as clock source)
„ Watch Dog Clock
„ Timer 0/1/2/3 Clock
„ PWM Clock
6.3.7 Frequency Divider Output
This device is equipped a power-of-2 frequency divider which is composed by16 chained divide-
by-2 shift registers. One of the 16 shift register outputs selected by a sixteen to one multiplexer is
reflected to P3.6. Therefore there are 16 options of power-of-2 divided clocks with the frequency
from F_in/2¹ to F_in/2¹⁷ where Fin is input clock frequency to the clock divider.
The output formula is F_out = F_in/2^(N+1), where F_in is the input clock frequency, F_out is the clock
divider output frequency and N is the 4-bit value in FREQDIV.FSEL[3:0].
When write 1 to DIVIDER_EN (FRQDIV[4]), the chained counter starts to count. When write 0 to
DIVIDER_EN (FRQDIV[4]), the chained counter continuously runs till divided clock reaches low
state and stay in low state.
CLKSEL2.FRQDIV_S[3:2]
22.1184M
11
HCLK
10
Ext. Crystal
00
APBCLK.FRQDIV_EN[6]
FRQDIV_CLK
Figure 6–8 Clock Source of Frequency Divider
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Publication Release Date: Mar 15, 2011
Revision V1.0