PM73121ꢀAAL1gator II
Data Sheet
PMC-Sierra, Inc.
PMC-980620
,VVXHꢀꢁ
AAL1 SAR Processor
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 psuedocode (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 the 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 play out the data from the R_DATA_BUF and the signaling from the R_SIG_
BUFFER. This is the normal operating state.
When there is no data in the frame buffer, the RFTC sets an underrun bit R_
UNDERRUN bit is cleared, and R_RD_FR_PTR = R_WR_FR_PTR. 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.
ꢅꢆ
PMC [ PMC-SIERRA, INC ]
