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GD32F20x User Manual
785
27.3.
Function overview
27.3.1.
Interface configuration
The Ethernet block can transmit and receive Ethernet packets from an off-chip Ethernet PHY
connected through the MII/RMII interface. MII or RMII mode is selected by software and carry
on the PHY management through the SMI interface.
SMI: Station management interface
SMI is designed to access and configure PHY’s configuration.
Station management interface (SMI) is performed through two wires to communicate with the
external PHY: one clock line (MDC) and one data line (MDIO), it can access to the any PHY
register. The interface supports accessing up to 32 PHYs, but only one register in one PHY
can be addressed at the same time.
MDC and MDIO specific functions as follows:
MDC: A clock of maximum frequency is 2.5 MHz. The pin remains low level when it is in
idle state. The minimum high or low level lasts time of MDC must be 160ns, and the
minimum period of MDC must be 400ns when it is in data transmission state.
MDIO: Used to transfer data in conjunction with the MDC clock line, receiving data from
external PHY or sending data to external PHY.
Figure 27-3.
Station management interface signals
SMI write operation
Applications need to write transmission data to the ENET_MAC_PHY_DATA register and
operate the ENET_MAC_PHY_CTL register as follows:
1) Set the PHY device address and PHY register address, and set PW to 1, so that can select
write mode.
2) Set PB bit to start transmission. In the process of transaction PB is always high until the
transfer is complete. Hardware will clear PB bit automatically.
The application can be aware of whether a transaction is complete or not through checking
PB bit. When PB is 1, it means the application should not change the PHY address register
contents and the PHY data register contents because of operation is running. Before writing
PB bit to 1, application must poll the PB bit until it is 0.
External PHY
SMI
MDC
MDIO
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 ...