HC4GX15 Datasheet, PDF (370/668 Pages) Altera Corporation – HardCopy IV Device Handbook

1–106
Chapter 1: HardCopy IV GX Transceiver Architecture
Receiver Channel Datapath
Figure 1–88. 8B/10B Decoder in Single-Width Mode
j hg f i e dc b a
9 87 65 4 3 21 0
MSB Received Last
8B/10B Conversion
LSB Received First
ctrl
7 6 5 4 3 2 1 0 Parallel Data
HG FE D CB A
Control Code Group Detection
The 8B/10B decoder indicates whether the decoded 8-bit code group is a data or
control code group on the rx_ctrldetect port. If the received 10-bit code group is
one of the 12 control code groups (/Kx.y/) specified in the IEEE802.3 specification,
the rx_ctrldetect signal is driven high. If the received 10-bit code group is a data
code group (/Dx.y/), the rx_ctrldetect signal is driven low.
Figure 1–89 shows the 8B/10B decoder decoding the received 10-bit /K28.5/ control
code group into an 8-bit data code group (8'hBC) driven on the rx_dataout port.
The rx_ctrldetect signal is asserted high synchronous with 8'hBC on the
rx_dataout port, indicating that it is a control code group. The rest of the codes
received are data code groups /Dx.y/.
Figure 1–89. 8B/10B Decoder in Control Code Group Detection
clock
datain[9..0 ]
D3.4 D24.3 D28.5 K28.5
D15.0 D0.0
D31.5
rx_ctrldetect
rx_dataout[7..0]
83
78
BC
BC
0F
00
BF
HardCopy IV Device Handbook Volume 3
© June 2009 Altera Corporation