cx29503 Mindspeed Technologies, cx29503 Datasheet - Page 151

• Manufacturer Part Number: cx29503
• Description: Cx29503 Broadband Access Multiplexer Data Sheet
• Manufacturer: Mindspeed Technologies

CX29503 Data Sheet
8.3.2.1
0x01—Primary Control Register (CR0)
The receive data stream contains an offline framer followed by an online framer. The offline framer recovers
receive frame alignment; the online framer monitors frame alignment patterns and recovers multiframe
alignment in E1 modes.
synchronization criteria used by the framers, and the monitoring criteria of the online framer, are selected in
RFRAME[3:0].
Receive frame synchronization is initiated by the online framer’s activation of the Receive Loss Of Frame
(RLOF) status bit in the Alarm 1 Status register [ALM1; addr: 047]. The RLOF criteria is set in the RLOFA,
RLOFB, RLOFC, and RLOFD bits of the Receiver Configuration register [RCR01; addr: 040]. The online
framer supports the following LOF criteria for T1: 2 out of 4, 2 out of 5, and 2 out of 6. For E1, the online
framer supports 3 out of 3, with or without 915 out of 1,000 CRC errors.
When RLOF is asserted, the offline framer automatically starts searching the receive data stream for a new
frame alignment, provided that receive framing is enabled [RABORT; addr: 040]. If receive framing is disabled,
the offline framer does not automatically search for the frame alignment, but waits for a reframe command
[RFORCE; addr: 040] to start a frame alignment search. If RLOF integration is enabled
[RLOF_INTEG; addr: 045] the RLOF status [ALM1; addr: 047] and RLOF interrupt status [ISR7; addr: 004] is
integrated for 2.0 to 2.5 seconds.
The online framer continuously monitors for loss of frame (RLOF) condition [ALM1; addr: 047] and searches
for E1 multiframe alignment after basic frame alignment is recovered by the offline framer. Receive multiframe
alignment is declared when multiframe alignment criteria are met. The receive online framer reports multiframe
errors, as well as frame errors and CRC errors in the Error Interrupt Status register [ISR5; addr: 006].
On the CX29503, the Transmit Offline framer is disabled by setting the TABORT bit of the Transmitter
Configuration register [TCR1; addr: 071]. On the CX29503, the Transmit Online framer is not implemented in
the device.
Unused and reserved bits should be written to 0.
RINCF
RFRAME[3:0]
29503-DSH-002-B
RESERVED
7
Table 8-6
Receiver Framer CRC6 includes the F-bit—Determines if the F-bit is included in the CRC6
remainder calculation in T1 mode (T1/E1N = 1). This bit is ignored in E1 mode (T11/
E1N = 0).
Receiver Framer Mode—Establishes the offline framer's search criteria for recovery of frame
alignment (reframe). Also works in conjunction with the RLOFA–RLOFD bits [addr: 040] to
establish the online framer's criteria for loss of frame alignment. Mode descriptions are given
in
alignment are also selected by RFRAME[3:0].
Table
—
6
Table 8-5
Primary Control Registers
0
1
8-5. The online framer’s SF and MFAS criteria for loss/recovery of multiframe
details framing loss and recovery criteria.
RINCF
5
lists the supported Receiver Framing modes. Frame and multiframe
Mindspeed Technologies™
RFRAME[3]
Preliminary Information
4
= T1 ESF CRC6 calculation is performed on the receive data
= TI ESF CRC6 transmit calculation is performed on receive
including a 1 in place of the F-bit
data including the F-bit
RFRAME[2]
3
RFRAME[1]
2
RFRAME[0]
1
Register Description
T1/E1N
0
8
-
21