CD00237391 Datasheet, PDF (162/177 Pages) STMicroelectronics – ARM-based 32-bit MCU, 150DMIPs, up to 1 MB Flash/128+4KB RAM

Application block diagrams
Figure 92. Audio player solution using PLL, PLLI2S, USB and 1 crystal
XTAL
25 MHz
or 14.7456 MHz
Div
by M
PLL
x N1
up to
Div ^{120 MHz}
by P
Div
by Q
PLLI2S Div
x N2
by R
Cortex-M3 core
up to 120 MHz
OTG
48 MHz
PHY
STM32F20xxx
MCO1/
MCO2
MCLK
in
MCO1PRE
MCO2PRE
I2S
<0.04%
accuracy)
MCLK out
SCLK
DAC +
Audio
ampli
ai18412b
Figure 93. Audio PLL (PLLI2S) providing accurate I2S clock
CLKIN
PLLI2S
Phase lock detector
/M
M=1,2,3,..,64
1 MHz
PhaseC ^{192 to 432 MHz}
VCO
/N
I2S_MCK = 256 × F_SAUDIO
11.2896 MHz for 44.1 kHz
12.2880 MHz for 48.0 kHz
N=192,194,..,432
I2SCOM_CK
/R
R=2,3,4,5,6,7
I2S CTL
I2S_MCK
I2SD=2,3,4.. 129
ai16041b
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Doc ID 15818 Rev 9