MU9C8338 10/100Mb Ethernet Filter Interface
Pin Descriptions
COL (Collision, Input, TTL)
RP[15:0] (Result Port Data, Output, Tri-state, TTL)
Collision detect COL is asserted by the PHY upon
detection of a collision on the medium and remains
asserted as long as the collision persists. It is HIGH in
half-duplex modes and remains HIGH for 1 microsecond
following the end of transmission; it is LOW in
full-duplex mode. It is asserted in response to
signal_quality_error message from the PMA in 10Base-X
Heartbeat mode.
The Result Port Data carries the results of recently
processed packets detected on the MII port. See Table 1
for details of the Result Port Data bit descriptions. These
are identical to the Result Data register bits.
RP_DV (Result Port Data Valid, Output TTL)
The Result Port Data Valid indicates that the RP port
carries valid packet data. As long as there is valid packet
data, RP_DV will stay HIGH.
Tag Port Interface
RP_NXT (Result Port Next Data, Input, TTL)
REJ (Reject, Output, TTL)
The Result Port Next pin brings the next result to the RP
bus if RP_SEL is asserted. If there are no additional results
available, the RP_DV will drop LOW after the time
interval specified in the Result Port Timing specification.
REJ is the reject packet command issued by the
MU9C8338. REJ is driven HIGH to reject a data frame,
and can be detected by and responded to by the MAC
device from 2 bit times after SFD to 512 bit times (64 byte
times) after SFD. The REJ signal can be made active
LOW by setting Bit 0 in the SSCFG register. (See Timing
Diagrams: REJ Timing Data.
RP_SEL (Result Port Select, Input, TTL)
The Result Port Select pin controls RP[15:0] and
RP_NXT. RP_NXT and RP_SEL are connected by a
logical AND. Therefore, RP_SEL must be HIGH in order
for RP_NXT to bring the next result to the RP bus.
RP_SEL can stay continuously HIGH as long as there is
valid packet data, RP_DV will stay HIGH.
FRX_ER (Frame Error, Output, TTL)
The Forced Receive Error pins provide the logical OR of
the RX_ER and REJ lines for the MII port (see Timing
Diagrams: Timing Data for FRX_ER in Relation to REJ
and RX_ER).
Table 1: Result Port Bit Descriptions
Bit(s)
15:10
9:8
Description
TP_SD (Tag Port Data, Output, TTL)
6-Bit Source Port ID
The Tag Port Serial Data pin carries the destination Port
ID to external circuitry as soon as it is collected from the
CAM (see Timing Diagrams: Timing Data for Tag Ports
TP_DV and TP_SD).
Packet Type: Broadcast = 00, Multicast = 01,
Unicast = 10
7
6:1
0
(if Unicast) Match Found
6-Bit (if CAM Match Found) Destination Port ID
(If Match Found) Destination Port = Source Port
TP_DV (Tag Port Data Valid, Output, TTL)
The Tag Port Data Valid pin is driven HIGH for as long as
unread data exists for the Destination Port ID. Pin TP_SD
carries the Destination Port ID (6 bits) to external circuitry
as soon as it is collected from the CAM (see Timing
Diagrams: Timing Data for Tag Ports TP_DV and
TP_SD).
Control Interfaces
See Timing Diagrams: Timing Data for Control Interfaces.
SYSCLK (System Clock, Input, TTL)
CLK is the user-supplied system clock for synchronous
chip operation; its frequency must be 25-50 MHz with
duty cycle between 45 to 55 percent.
Result Port Interface
See Timing Diagrams: Timing Data for Result Port
/RESET (Reset, Input, TTL)
Interface. Table 1 shows the Result Port bit descriptions.
When system Reset is taken LOW, all internal
state-machines are reset to their initial state and any data is
cleared. All registers are returned to default values.
/RESET is synchronous and should be held LOW for a
minimum of two SYSCLK cycles. The user must set the
LANCAM Segment Control register after asserting
/RESET.
Note: Although the result data register can also be read through
the processor port, it is important to note that the means of
retrieving the data must be unique. Therefore, if the user is not
using the Result Port Interface, but is reading result data through
the processor port, RP_NXT and RP_SEL should be pulled low.
This ensures that all result data remains in the Result Data
register until read through the processor port. RP_NXT and
RP_SEL should be pulled low to 0 volts through a pull-down
resistor (typically 10k ohms).
4
Rev. 1a
MUSIC [ MUSIC SEMICONDUCTORS ]
