Freescale Semiconductor MPC8260 - Manual (Page 1033)

ATM AAL1 Circuit Emulation Service
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 31-17
Table 31-2 describes CES adaptive threshold table fields.
0 7 8 15
Offset + 0x00 — CES Adaptive Counter
Offset + 0x02 ATM Stop Threshold ATM Start Threshold
Offset + 0x04 MCC Stop Threshold MCC Start Threshold
Offset + 0x06 —
Figure 31-15. CES Adaptive Threshold Table
Table 31-2. CES Adaptive Threshold Table Field Descriptions
Offset
1
1
The offset is CATB + RCT[Super_Channel_Number]# × 8
Bits Name Description
0x00 0-7 — Reserved, should be cleared during initialization.
8-15 CESAC CES adaptive counter.This field contains the difference between the ATM write pointer and
the MCC read pointer on the common BD table.This field should be cleared by the user
during the channel initialization.
0x02 0-7 ASTP ATM stop threshold.This threshold determines the maximum amount of buffering (CDVT)
that required in the common BD table (shown in
Figure 31-16 ). When the CESAC reaches
this value a pre-overrun condition occurs.This field should be defined by the user during the
channel initialization.
8-15 ASTRT ATM start threshold.This threshold determines the Time interval that will take the ATM
controller to restart the synchronize process (shown in
Figure 31-16 ) after pre-overrun
condition.This field should be defined by the user during the channel initialization.
0x04 0-7 MSTP MCC stop threshold.This threshold determines the minimum amount of buffering in the
common BD table (shown in
Figure 31-16 ).When the CESAC reaches this value a
pre-underrun condition occur and the MCC starts to transmit the underrun template or the
last BD (see
Section 31.5, “ATM-to-TDM Adaptive Slip Control ”).This field should be defined
by the user during the channel initialization.
8-15 MSTRT MCC start threshold.This threshold determines the effective depth of the jitter buffer, the
amount of buffering required to cope with the ATM network’s CDV (shown in
Figure 31-16 ).When the CESAC reaches this value the MCC transmitter starts sending the
valid data from the common BD table.This field should be defined by the user during the
channel initialization.
0x06 0-15 — Reserved, should be cleared during initialization.