NetFPGA 1G CML mdio_ctrl_v1_00_a

Name

mdio_ctrl

Version

v1.00a

Type

pcore (HW)

Location

lib/hw/contrib/pcores/mdio_ctrl_v1_00_a

Interface Types

AXI-Lite, MDIO

Busses

None

Description

A generic MDIO interface for communicating with PHYs on the bus. It also provides extended resets to the PHYs at reset.

Features

• Supports a variable number of PHY reset signals.
• Follows the same register format of the Xilinx AXI Ethernetlite core MDIO interface (Registers 0x07e4 - 0x07f0 from DS787).

Parameters

Parameter	Description
C_MDIO_CLK_DIV	MDIO Clock Divisor. Use the function ceil(((S_AXI_ACLK Frequency) / (Desired MDIO clock frequency)) / 2) to determine the value of this parameter.
C_NUM_PHY	Number of PHYs on the MDIO bus. This determines the width of the reset signal.

Register map

Offset	Name	Description
0x00	MDIOADDR	MDIO address register
0x04	MDIOWR	MDIO write data register
0x08	MDIORD	MDIO read data register
0x0c	MDIOCTRL	MDIO control register

Register Descriptions

MDIOADDR - MDIO Address Register

Bits	Meaning
[31 - 11]	Reserved
[10]	Operation: 0 - write, 1 - read
[9 - 5]	PHY Address
[4 - 0]	Register Address

MDIOWR - MDIO Write Data Register

Bits	Meaning
[31 - 16]	Reserved
[15 - 0]	Data to write to PHY register

MDIORD - MDIO Read Data Register

Bits	Meaning
[31 - 16]	Reserved
[15 - 0]	Data read from PHY register

MDIOCTRL - MDIO Control Register

Bits	Meaning
[31 - 4]	Reserved
[3]	Enable: 0 - Disable interface, 1 - Enable interface
[2 - 1]	Reserved
[0]	Status: 0 - Ready for new request, 1 - Transfer in progress. Set

        |   this bit to initiate a transfer.

Programming Method

Writes

1. Wait until not busy. Check MDIOCTRL bit 0.
2. Store PHY address, register address, and a 0 to bit 10 of MDIOADDR.
3. Write data to MDIOWR.
4. Enable MDIO by writing a 1 to bit 3 of the MDIOCTRL register.
5. Initiate transfer by writing a 1 to bit 0 of the MDIOCTRL register. Also, rewrite the enable bit at bit 3. Basically, you'll be writing a 0x9 to the register.
6. Check MDIOCTRL bit 0 to see when the transfer has completed.

Reads

1. Wait until not busy. Check MDIOCTRL bit 0.
2. Store PHY address, register address, and a 1 to bit 10 of MDIOADDR.
3. Enable MDIO by writing a 1 to bit 3 of the MDIOCTRL register.
4. Initiate transfer by writing a 1 to bit 0 of the MDIOCTRL register. Also, rewrite the enable bit at bit 3. Basically, you'll be writing a 0x9 to the register.
5. Check MDIOCTRL bit 0 to see when the transfer has completed.
6. Read data from MDIORD