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RELEASED
PM73122 AAL1GATOR-32
DATASHEET
PMC-1981419
ISSUE 7
32 LINK CES/DBCES AAL1 SAR PROCESSOR
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
132
and 16), data and signaling for all 32 timeslots are stored in memory and can
be sent and received in cells.
Each line request is serviced by the main RFTC state machine using a priority
encoder (line 0 has the highest priority). The line requests two bytes at a time.
This means two channels have to be serviced by the RFTC state machine.
When the RFTC state machine receives an attention request from a line, it
services the request according to the following pseudocode (please note that the
bits discussed are maintained in R_LINE_STATE in the queue tables and should
not be confused with the externally accessible sticky bits):
If the RX_COND_H (or RX_COND_L) = “10”, play out the data from the
R_COND_DATA area and signaling from the R_COND_SIG area. This is the
conditioned state.
Else if either the R_UNDERRUN bit or the R_RESUME bit is set in
R_LINE_STATE, then play out the data and signaling as determined by the
value of RX_COND_H (or RX_COND_L). This is the frozen signaling state.
The data played out can either be constant, pseudorandom, or old data.
Else if DBCS_EN=’1’ and the channel is inactive; then play out the data and
signaling as determined by the value of RX_COND_ (or RX_COND_L) as if in
underrun.
Else play out the data from the R_DATA_BUF and the signaling from the
R_SIG_BUFFER. This is the normal operating state.
In any of the above states, the conditioned signaling may be forces by setting
the RX_SIG_CONDH( or RX_SIG_COND_L)
When there is no data in the frame buffer, the RFTC sets an underrun bit,
R_UNDERRUN. The RALP clears R_UNDERRUN and sets R_RESUME
when it encounters the first valid cell in the receive buffer.
If the R_RESUME bit is set and the R_RD_FR_PTR =
R_END_UNDERRUN_PTR, then RFTC clears the R_RESUME bit. This
occurs one CDVT time after the first valid cell arrives. If the line is in SDF_MF
mode, then R_SIG_RESUME is set to indicate that signaling is not yet
available. Once a multiframe has completed and signaling data is available,
R_SIG_RESUME will be cleared.
Figure 57 shows the channel-to-queue table operation