Txdrven; Pmainit; Sel_Dac_Tran[3:0]; Sel_Dac_Fix[3:0] - Xilinx RocketIO X User Manual

R

TXDRVEN

TXDRVEN enables and disables transmit line driver operation. The default is 1 (Enabled).
For proper operation, the bias and transmitter must also be enabled. The transmit line
driver control is defined as follows:

Table C-45: TXDRVEN Definition

PMAINIT

When PMAINIT is asserted (High), the FPGA configuration attributes are automatically
loaded into the PMA. This overwrites any PMA attribute modifications made via the
PMA attribute programming bus. This feature can be used to restore the FPGA bitstream
configuration from memory or to load newly configured attributes following a partial
reconfiguration. Because of the automatic configuration process used to load PMA
attributes after assertion of PMAINIT, the PMA attribute programming bus has no
operational effect until

SEL_DAC_TRAN[3:0]

This attribute is used to program the transition current in the fine loop charge pump. The
default setting sets the current to its nominal value and should be set to 0000. See
Density Independent Phase Adjustment for CDR."

SEL_DAC_FIX[3:0]

This attribute is used to program the fixed current in the fine loop charge pump. The
default setting set the current to its nominal value and should be set to 0000. See
Density Independent Phase Adjustment for CDR."

ENDCD

This attribute enables better transmitter jitter performance. The default value is mode-
dependent. It is 1 for high-speed operation (greater than or equal to 5 Gb/s) or 0 for low-
speed operation (less than 5 Gb/s).

AFE_FLAT_ENABLE

This attribute makes the AFE response flat (no peaking). The default is 0.

Data-Density Independent Phase Adjustment for CDR

This section describes the programmability of the fine loop charge pump (CP) to achieve
offset adjustment that is data-density independent. The fine loop CP is made of a Phase CP,
Transition CP, and DC current sources as shown in
164
TXDRVEN TX Line Driver Operation
0
1
TBD ms after the deassertion of PMAINIT.
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Appendix C: PMA Attribute Programming Bus
Disabled
Enabled (Default)
Figure
RocketIO™ X Transceiver User Guide
"Data-
"Data-
C-2.
UG035 (v1.5) November 22, 2004