BT8954 CONEXANT [Conexant Systems, Inc], BT8954 Datasheet - Page 62

• Manufacturer Part Number: BT8954
• Description: VOICE PAIR GAIN FRAMER
• Manufacturer: CONEXANT [Conexant Systems, Inc]

4.0 Registers
4.5 Receiver Registers
LOSS_SYNC[2:0]
REACH_SYNC[2:0]
TEST_RSFIFO
PD_LOOP
4-10
0x91—Receive Command Register 2 (RCMD_2)
TEST_RSFIFO
7
PD_LOOP
Loss of Sync Framing Criteria—Contains the number of consecutive DSL frames in which the
SYNC word is not detected before the receive framer moves from the IN_SYNC to the
OUT_OF_SYNC state. LOSS_SYNC determines the number of SYNC_ERRORED
intermediate states the framer must pass through during loss of frame sync. ETSI standard
criteria require six consecutive frames without SYNC word detected.
Reach Sync Framing Criteria—Contain the number of consecutive DSL frames in which the
SYNC WORD is detected before the receive framer moves from the OUT_OF_SYNC to the
IN_SYNC state. REACH_SYNC determines the number of SYNC_ACQUIRED intermediate
states the framer must pass through during recovery of frame sync. ETSI standard criteria
require two consecutive frames containing SYNC.
Test Receive Signaling FIFO—Enables the copying of RSFIFO_I into RSFIFO_O, and write
access to RSFIFO_I by the MC. Setting this bit enables the testing of the RSFIFOs from the
MC.
Loopback to PCM on DSL Side—Transmit DSL data (TDAT) is connected back toward the
PCM interface to accomplish a loopback of the PCM channel on the DSL side. Receive DSL
data (RDAT) is ignored, but DSL transmit continues without interruption. PD_LOOP requires
the descrambler and scrambler to use the same tap, as opposed to their normal opposing tap
selection.
6
DSCRAM_EN
5
0 = Disabled testing of RSFIFOs; enabled normal operation
1 = Enabled testing of RSFIFOs; disabled normal operation
0 = Normal receive
1 = RDAT supplied by TDAT
DSCRAM_TAP
REACH_SYNC
LOSS_SYNC
4
000
001
010
011
100
101
110
111
000
001
010
011
100
101
110
111
Conexant
3
1 frame containing SYNC
1 frame not containing SYNC
2 consecutive frames
3 consecutive frames
4 consecutive frames
5 consecutive frames
6 consecutive frames
7 consecutive frames
8 consecutive frames
OUT_OF_SYNC Criteria
IN_SYNC Criteria
2 consecutive frames
3 consecutive frames
4 consecutive frames
5 consecutive frames
6 consecutive frames
7 consecutive frames
8 consecutive frames
2
THRESH_CORR[3:0]
1
Voice Pair Gain Framer
N8954DSC
Bt8954
0