The GTY and GTYP transceiver contains 2-byte, 4-byte, and 8-byte internal datapaths and is configurable by setting the RX_INT_DATA_WIDTH attribute. The interface width is configurable by setting the RX_DATA_WIDTH attribute. When the 8B/10B decoder is enabled, RX_DATA_WIDTH must be configured to 20 bits, 40 bits, or 80 bits, and in this case, the RX interface only uses the CH*_RXDATA ports. For example, CH*_RXDATA[15:0] is used when the interface width is 16. When the 8B/10B decoder is bypassed, RX_DATA_WIDTH can be configured to any of the available widths: 16, 20, 32, 40, 64, 80, 128, or 160 bits.
The following table shows how the interface width for the RX datapath is selected. 8B/10B decoding is described in more detail in RX 8B/10B Decoder.
| 8B10B | RX_DATA_WIDTH | RX_INT_DATA_WIDTH | Interface Width | Internal Data Width |
|---|---|---|---|---|
| Disabled |
4'b0010
|
2'b00
|
16 | 16 |
4'b0011
|
2'b00
|
20 | 20 | |
4'b0100
|
2'b00
|
32 | 16 | |
4'b0100
|
2'b01
|
32 | 32 | |
4'b0101
|
2'b00
|
40 | 20 | |
4'b0101
|
2'b01
|
40 | 40 | |
4'b0110
|
2'b01
|
64 | 32 | |
4'b0110
|
2'b10
|
64 | 64 | |
4'b0111
|
2'b01
|
80 | 40 | |
4'b0111
|
2'b10
|
80 | 80 | |
4'b1000
|
2'b10
|
128 | 64 | |
4'b1001
|
2'b10
|
160 | 80 | |
| Enabled |
4'b0011
|
2'b00
|
16 | 20 |
4'b0101
|
2'b00
|
32 | 20 | |
4'b0101
|
2'b01
|
32 | 40 |
When the 8B/10B decoder is bypassed and RX_DATA_WIDTH is 160, the CH*_RXCTRL0 and CH*_RXCTRL1 ports are used to extend the RXDATA port from 128 to 160 bits. The following figure shows the data received when the 8B/10B decoder is disabled. When the RX gearbox is used, refer to RX Synchronous Gearbox for data transmission order.
