
E-110 Core Interface Signals
3-29
bytes, the receive function asserts only the E110_RPDV
signal until the last byte, when it asserts both
E110_RPDV and E110_RPEF.
E110_RRST_L
Receive Reset
Input
Other modules in an ASIC can use the E110_RRST_L
signal as a host reset synchronized to the receive clock
(MII_RCLK). Because the MII_RCLK clock can be slow
with respect to a host reset pulse, or even stopped, the
host reset signal (E110_HRST_L) is captured in the
E-110 MAC receive function, which asserts
E110_RRST_L asynchronously to MII-RCLK when
E110_HRST_L occurs and deasserts E110_RRST_L
synchronously on the positive transition of MII_RCLK.
E110_AUTOPAD_ENABLE
E-110 Autopadding Enable
Output
The E110_AUTOPAD_ENABLE signal, when asserted,
instructs the transmit function to pad packets of fewer
than 60 bytes with a sufcient number of bytes of zero
such that the minimum packet size (64 bytes, including
data plus an FCS of 4 bytes) specied by IEEE 802.3 is
maintained.
When deasserted, E110_AUTOPAD_ENABLE disables
the padding of packets. For padding to take place, both
E110_AUTOPAD_ENABLE and E110_CRCEN must be
asserted. E110_AUTOPAD_ENABLE is synchronous with
the rising edge of the MII_TCLK clock and may be
asserted or deasserted when the transmit engine is idle
(either during reset or when no packet is being
transmitted).
E110_VLAN_PKT
E-110 VLAN Packet Detect
Input
The MAC asserts the E110_VLAN_PKT signal to indicate
that the current received packet has a valid
Ethernet-encoded Tag Protocol Identier (TPID). The
encoded TPID for the MAC is 81-00. Assertion of
E110_VLAN_PKT also indicates that the
E110_VLAN_CFI, E110_VLAN_PRIORITY[2:0], and
E110_VLAN_RPVID[11:0] signals are valid. The MAC
deasserts E110_VLAN_PKT at the beginning of the next
packet.