BT8954 CONEXANT [Conexant Systems, Inc], BT8954 Datasheet - Page 73

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

Bt8954
Voice Pair Gain Framer
Writing any data value to RFIFO_RST empties the RFIFO and forces the payload mapper to realign DSL bytes
with respect to the receive DSL 6 ms frame. The MC must write RFIFO_RST whenever an RFIFO error is
reported [RSTATUS_1; 0xE5], and after the PLL has settled. Writing RFIFO_RST corrupts up to three receive
PCM frames worth of data.
Writing any data value to SYNC_RST forces the receive framer to the OUT_OF_SYNC state, which restarts the
SYNC word search and causes the framer to issue an RX_ERR interrupt [ISR; 0xD0.3]. The MC must write
SYNC_RST after modifying FRAMER_EN [RCMD_1; 0x90.6], or SYNC_WORD. Writing SYNC_RST
corrupts up to three receive PCM frames worth of data.
Writing any data value to ERR_RST clears the receive CRC Error Counter [CRC_CNT; 0xE8], the receive Far
End Block Error Counter [FEBE_CNT; 0x6E9] and consequently clears the counter overflow CRC_OVR and
FEBE_OVR bits [RSTATUS_2; 0xE6.6:7]. ERR_RST clears the error counters immediately and must be issued
within 6 ms after the respective receive frame interrupt in order to avoid clearing unreported errors. No other
receive errors (CRC_ERR or RFIFO) are affected by ERR_RST.
Writing any data value to RX_RST forces the PCM formatter to align the PCM receive timebase with respect to
the DSL channel’s receive 6 ms frame by reloading the RFIFO_WL value [0xA2, 0xA3]. The MC must write
RX_RST after modifying the RFIFO_WL value. Bt8954 automatically performs RX_RST each time the receive
framer changes alignment and transitions to the IN_SYNC state, if the EN_AUTO_RFIFO_RST is set.
timebase.
Writing any data value to UPDATE_TSFIFO_O initiates a copy of TSFIFO_I into TSFIFO_O. This is only used
for testing.
Writing any data value to UPDATE_RSFIFO_O initiates a copy of RSFIFO_I into RSFIFO_O. This is only
used for testing.
N8954DSC
0xD7—Receive Elastic Store FIFO Reset (RFIFO_RST)
0xD8—Receive Framer Synchronization Reset (SYNC_RST)
0xD9—Error Count Reset (ERR_RST)
0xDA—Reset Receiver (RX_RST)
0xDB—Update TSFIFO_O (UPDATE_TSFIFO_O)
0xDC—Update RSFIFO_O (UPDATE_RSFIFO_O)
Issuing RX_RST while the PCM formatter is aligned causes no change in alignment of the PCM receive
Conexant
4.0 Registers
4.10 Reset
4-21