VHDL Design of Interface between Single Chip Microcomputer and Ethernet Controller RTL8029

1 Ethernet controller

The Ethernet controller of Taiwan Realtek is a controller that complies with the IEEE802.3 Ethernet standard. There are RTL8019, RTL8029 and RTL8139 series. Among them, RTL8019 is ISA bus, which is easier to interface with 8-bit MCU. RTL8029 and RTL8139 are PCI bus, which cannot directly interface with 8-bit MCU, and need a PCI interface for conversion. Considering that RTL8029 is easier to buy in the market, the RTL8029 Ethernet controller is used as the network interface.

RTL8029 already contains the entire network interface layer protocol (PHY layer and MAC layer protocol), so it is relatively simple to use. Users do not need to consider link control issues, but only need to consider how the microcontroller reads TCP/IP protocol data from RTL8029.

PCI bus signals have 3.3V standard and 5V standard, and there are many signal lines, but not all PCI devices use all PCI interface signals. In fact, only the ones they need are used. The RTL8029AS Ethernet controller follows the 5V standard and only uses the following parts of the PCI bus signals:

AD[31:0]——Data signal multiplexing bus.
FRAME——Frame cycle signal, driven by the current master device, indicating the start and duration of an access.
IRDY——Master device ready signal.
TRDY——Slave device ready signal.
C/BE——Bus command and byte enable multiplexing signal. The address period is the bus command, and the data period is the byte enable.
IDSEL——Initialization device selection signal. Used as chip select during parameter configuration read and write transmission. For the case where there is only one PCI device, it can always be connected to a high level.
RST——Reset signal.
CLK——System clock signal, frequency range DC~33MHz. The above signals are all valid on the rising edge of CLK.
INTA——Interrupt request signal, which can be used to send an interrupt to the main controller after the RTL8029 data is ready.
DEVSEL——Device selection signal, indicating that the device driving it has become the currently accessed device. Since in the single-chip microcomputer system, RTL8029 is a single PCI device, this signal can be ignored.

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