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Internal PHY
MOSC
25 MHz
PTPCEN
Ethernet MAC
EN0RXIP
EN0RXIN
EN0TXOP
EN0TXON
RBIAS
EN0MDIO
EN0MDC
EN0INTRN
TX
RX
EN0LED2
EN0LED1
EN0LED0
Gated SYSCLK
PTP_REFCLK
MAC Control /
Status Registers
EMACCC
MSP432E
Microcontroller
Functional Description
885
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Ethernet Controller
Figure 15-2. Ethernet MAC and PHY Clock Structure
15.3.1.2 Media-Independent Interface (MII)
Four clock inputs are driven into the Ethernet MAC when the MII configuration is enabled. The clocks are
described as follows:
•
Gated system clock (SYSCLK): The SYSCLK signal acts as the clock source to the Control and Status
registers (CSR) of the Ethernet MAC. The SYSCLK frequency for Run, Sleep, and Deep Sleep mode
is programmed in the System Control module. See
for more information on programming
SYSCLK and enabling the Ethernet MAC.
•
MOSC: A gated version of the MOSC clock is provided as the PTP reference clock (PTPREF_CLK).
The MOSC clock source can be a single-ended source on the OSC0 pin or a crystal on the OSC0 and
OSC1 pins. When advanced timestamping is used and the PTP module has been enabled by setting
the PTPCEN bit in the EMACCC register, the MOSC drives PTPREF_CLK. PTPREF_CLK has a
minimum frequency requirement of 5 MHz and a maximum frequency of 25 MHz. See
for more information.
•
EN0RXCK: This clock signal is driven by the external PHY oscillator and is either 2.5 or 25 MHz,
depending on whether the device is operating at 10 Mbps or 100 Mbps.
•
EN0TXCK: This clock signal is driven by the external PHY oscillator and is either 2.5 or 25 MHz,
depending on whether the device is operating at 10 Mbps or 100 Mbps.
shows the clock inputs for an MII.