RM0090: Reference manual - STMicroelectronics

RM0090 Ethernet (ETH): media access control (MAC) with DMA controller
1. Disable the transmit DMA and wait for any previous frame transmissions to complete.
These transmissions can be detected when the transmit interrupt ETH_DMASR
register[0] is received.
2. Disable the MAC transmitter and MAC receiver by clearing the RE and TE bits in the
ETH_MACCR configuration register.
3. Wait for the receive DMA to have emptied all the frames in the Rx FIFO.
4. Disable the receive DMA.
5. Configure and enable the EXTI line 19 to generate either an event or an interrupt.
6. If you configure the EXTI line 19 to generate an interrupt, you also have to correctly
configure the ETH_WKUP_IRQ Handler function, which should clear the pending bit of
the EXTI line 19.
7. Enable Magic packet/Wake-on-LAN frame detection by setting the MFE/ WFE bit in the
ETH_MACPMTCSR register.
8. Enable the MAC power-down mode, by setting the PD bit in the ETH_MACPMTCSR
register.
9. Enable the MAC Receiver by setting the RE bit in the ETH_MACCR register.
10. Enter the system’s Stop mode (for more details refer to Section 5.3.4: Stop mode):
11. On receiving a valid wakeup frame, the Ethernet peripheral exits the power-down
mode.
12. Read the ETH_MACPMTCSR to clear the power management event flag, enable the
MAC transmitter state machine, and the receive and transmit DMA.
13. Configure the system clock: enable the HSE and set the clocks.
29.5.9 Precision time protocol (IEEE1588 PTP)
The IEEE 1588 standard defines a protocol that allows precise clock synchronization in
measurement and control systems implemented with technologies such as network
communication, local computing and distributed objects. The protocol applies to systems
that communicate by local area networks supporting multicast messaging, including (but not
limited to) Ethernet. This protocol is used to synchronize heterogeneous systems that
include clocks of varying inherent precision, resolution and stability. The protocol supports
system-wide synchronization accuracy in the submicrosecond range with minimum network
and local clock computing resources. The message-based protocol, known as the precision
time protocol (PTP), is transported over UDP/IP. The system or network is classified into
Master and Slave nodes for distributing the timing/clock information. The protocol’s
technique for synchronizing a slave node to a master node by exchanging PTP messages is
described in Figure 342.
Doc ID 018909 Rev 3 934/1416