CD00237391 Datasheet, PDF (165/177 Pages) STMicroelectronics – ARM-based 32-bit MCU, 150DMIPs, up to 1 MB Flash/128+4KB RAM

STM32F20xxx
Application block diagrams
Figure 98. RMII with a 25 MHz crystal and PHY with PLL
MCU
HCLK(1)
STM32F
Ethernet
MAC 10/100
IEEE1588 PTP
Timer
input
TIM2
trigger
Timestamp
comparator
RMII_TX_EN
RMII_TXD[1:0]
RMII_RXD[1:0]
RMII_CRX_DV
RMII_REF_CLK
MDIO
MDC
Ethernet
PHY 10/100
RMII
= 7 pins
REF_CLK
RMII + MDC
= 9 pins
XTAL
25 MHz
/2 or /20
2.5 or 25 MHz _synchronous 50 MHz
OSC
PLL
HCLK
PLL
MCO1/MC02 ^{PHY_CLK 25 MHz XT1}
MS19970V1
1. f_HCLK must be greater than 25 MHz.
2. The 25 MHz (PHY_CLK) must be derived directly from the HSE oscillator, before the PLL block.
Doc ID 15818 Rev 9
165/177