Appendix C: Pma Attribute Programming Bus; Interface Description; Table C-1: Pma Attribute Bus Ports - Xilinx RocketIO X User Manual

R
PMA Attribute Programming Bus
The RocketIO X transceivers provide a simple, parallel programming bus for dynamically
configuring the PMA attribute settings. This gives the end user real-time control of PMA
features without the need to use partial reconfiguration or to bring out discrete control
ports to the fabric for each and every attribute (not feasible).
Note:
1.
2.
3.

Interface Description

The PMA attribute programming bus consists of a simple, strobed, byte-wide interface.
The user accessible ports are defined in
PMAINIT cycle, these ports have no effect on PMA attributes.

Table C-1: PMA Attribute Bus Ports

RocketIO™ X Transceiver User Guide
UG035 (v1.5) November 22, 2004
This feature is for ADVANCED USERS ONLY. Direct modification of these attributes
should only be done with a thorough understanding of the capabilities, performance,
and side-effects of the resulting settings. For most applications, the default PMA
attribute settings provided in the software primitives should be adequate.
The attribute bus is not user accessible during normal FPGA configuration or a
PMAINIT cycle (internally controlled for PMA initialization). Control is passed back
to the fabric TBD ms after initialization.
The previous bitstream configuration settings of the PMA attributes are restored after
assertion of PMAINIT and the subsequent initialization cycle, thus overwriting any
modifications via the attribute programming bus.
Port
PMAREGADDR[5:0]
PMAREGDATAIN[7:0]
PMAREGSTROBE
PMAREGRW
(1)(2)
TXRUNDISP
Notes:
1. TXRUNDISP is the Register Data Out when PMAREGADDR[5] is asserted; otherwise, it indicates the
TX running disparity.
2. All read data must be inverted.
Table C-1. During FPGA configuration or a
Register Address
Register Data In (from FPGA to PMA register)
Strobe Asserted Low
Read Asserted High/Write Asserted Low
Register Data Out (from PMA register to FPGA)
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Appendix C
Description
147