mcs7830 MosChip, mcs7830 Datasheet - Page 14

• Manufacturer Part Number: mcs7830
• Description: Usb-2.0 To Ethernet
• Manufacturer: MosChip

Page 14
MCS7830
USB-2.0 to Ethernet
Status Flow (Ethernet to USB):
Endpoint-3 (Interrupt-In) is in charge of returning the current Ethernet transfer status each polling interval. When
this endpoint is accessed, eight words of data are returned. These eight words contain the status vectors of
eight consecutive Ethernet frames transmitted from USB to Ethernet. These vectors describe frames pending
information in the SRAM (from Ethernet to USB path), 10/100 Link Status etc. as explained below.
Whenever the Interrupt-In endpoint is selected, eight status vectors are available in the FIFO. After reading
these eight words, software is supposed to verify bit-15 and bit-14 of each word. If bit-15 is ‘1’ that indicates
some frames are pending in the SRAM, if bit-14 is ‘1’ it indicates the least signifi cant four bits of the word are a
valid TX status vector. If bit-15 and bit-14 are both zeros, then the status vector should be ignored.
Bit-15
Bit-7
[9:4]
1/0
Bit
10
11
12
13
14
15
0
0
1
2
3
Reserved, (all zeros).
FULL_DUPLEX_EN: Indicates Full-Duplex or Half-Duplex operation.
MIIM_ INTERRUPT
Used as interrupt pin when an external PHY is connected.
MIIM_LINK
Indicates the status of the link when an external PHY is used.
0:
1:
0:
1:
0:
1:
0:
1:
0:
1:
0:
1:
0:
1:
0:
1:
Bit-14
Bit-6
1/0
0
Indicates the Ethernet frame transmitted is not correct.
Indicates the transmitted Ethernet frame is OK.
Indicates the number of retries is less than or equal to 16.
Indicates the number of retries is more than 16.
Indicates collision occurred before receiving 64 Bytes.
Indicates collision occurred after receiving 64 Bytes.
Normal
Indicates that the packet is aborted because of excessive deferral (if number
of clock cycles waited to transmit a packet is (TX CLK) more than 6072.)
Half-Duplex
Full-Duplex
Indicates 10 Mbps Ethernet speed.
Indicates 100 Mbps Ethernet speed.
Indicates least signifi cant four bits do not indicate valid status.
Indicates the least signifi cant four bits have a valid TX status.
Frames are not available in the Single-Port SRAM.
Indicates frames are pending in the Single-Port SRAM which have been
received from the Ethernet RX.
Bit-13
Bit-5
1/0
0
Bit-12
Bit-4
1/0
0
Description
Bit-11
Bit-3
1/0
1/0
Bit-10
Bit-2
1/0
1/0
Bit-9
Bit-1
1/0
0
Bit-8
Bit-0
1/0
0
Rev.
3.1