B
Appendix B: Bt8953A/RS8953B
Product Bulletin
B.1 BCLK Phase Constraints In Repeater Mode;
Non-Conformance Product Affected: Bt8953A and
RS8953B
While in repeater mode (REPEAT_EN = 1 for CH1 and CH2), a BCLK1 to
BCLK2 phase difference of 180 degrees, +/- 5 nSec, will result in corrupted data
transfer. All other phase relationships are acceptable.
In a repeater mode application, to prevent a phase difference of 180 degrees
between BCLK1 and BCLK2, the same clock is feed to both BCLK1 and
BCLK2. To use the same clock for both HDSL transceivers, one HDSL
transceiver needs to be slaved to the other HDSL transceiver. This is
accomplished by setting the HDSL transceiver, which is configured as HTU-C, to
“parallel slave mode.” Then the parallel signals from the HDSL transceiver need
to be externally converted to “serial, sign first mode” to interface to the
Bt8953A/RS8953B.
To configure the ZipWire transceiver to “parallel slave mode”, address 0x06
of the ZipWire transceiver needs to be modified. Also to align the sign and
magnitude data correctly, the tbclk_pol and rbclk_pol need to set properly. The
tbclk_pol and rdbclk_pol are controlled by address 0x06 of the ZipWire
transceiver. TQ[1,0] should be sampled on the falling edge of TBCLK. RQ[1,0]
should be updated on the falling edge of RBCLK.
N8953BDSB
Conexant
B-1
CONEXANT [ CONEXANT SYSTEMS, INC ]
