TLK6002 Datasheet, PDF (30/96 Pages) Texas Instruments – Dual Channel 0.47Gbps to 6.25Gbps Multi-Rate Transceiver

TLK6002
SLLSE34 – MAY 2010
TDA_[19: 0]
T X CLK_ A
RDA_[19: 0]
RXCLK_A
Parallel to
Serial
Channel A
www.ti.com
TXAP
TXAN
COMMA
Detect &
8B/ 10 B
Decoding
Serial to
Parallel
Channel A
RXAP
RXAN
TDB_[19: 0]
T X CLK_ B
Parallel to
Serial
Channel B
TXBP
TXBN
RDB_[ 19: 0]
RXCLK_B
COMMA
Detect &
8B/ 10 B
Decoding
Serial to
Parallel
Channel B
RXBP
RXBN
Figure 2-11. TLK6002 – Serial Retime Mode of Operation
2.19 Latency Measurement Function
The TLK6002 includes a round trip latency measurement function to support CPRI and OBSAI base
station applications. The elapsed time from a comma (either encoded or unencoded) detected in the
transmit direction of a particular channel to a comma detected in the receive direction of the same channel
is measured and reported through the MDIO interface (TDA_[19:0] → RDA_[19:0] -or- TDB_[19:0] →
RDB_[19:0]). The function operates on one channel at a time. When 8b/10b encoding/decoding is
enabled, the following three control characters (containing commas) are monitored:
1. K28.1 (control = 1, data = 0x3C)
2. K28.5 (control = 1, data = 0xBC)
3. K28.7 (control = 1, data = 0xFC).
When 8b/10b encoding/decoding is disabled, the lower 7 bits of the Tx and Rx data stream are monitored
for either positive (7’b0011111) or negative (7’b1100000) comma characters.
Whether 8b/10b encoding/decoding is enabled or not, comma detection in the receive datapath must be
enabled (register bit 3.7).
The result of this measurement is readable through the MDIO interface through a 20-bit register. The
accuracy of the measurement is a function of the serial bit rate which the channel being measured is
operating at. The register will return a value of 0xFFFFF if the duration between transmit and receive
comma detection exceeds the depth of the counter. Only one measurement value is stored internally until
the 20-bit results counter is read. The counter will return zero in cases where a transmit comma was never
detected (indicating the results counter never began counting).
30
Description
Submit Documentation Feedback
Product Folder Link(s): TLK6002
Copyright © 2010, Texas Instruments Incorporated