Freescale Semiconductor PowerQUICC MPC870, Reference Manual

Page: 1031 / 1426

ATM Controller
MPC885 PowerQUICC Family Reference Manual, Rev. 2
Freescale Semiconductor 39-9
39.3.1 Running a Performance Block Test
The following setup is required to run a block test on an active virtual channel connection VCC (OAM F5
PM):
1. Assign one of the available 64 performance monitoring tables by writing to both RCT[RPMT] and
TCT[TPMT] and initializing the one chosen (see Section 39.3.4, “Performance Monitoring
Tables” ).
2. Set the PM bit in the RCT or TCT or both.
Note that the TCTs/RCTs of active channels should be programmed using the
WRITE TO MEMORY
command. After the above setup, whenever a cell is received for this VCC, the TRCC counters are updated
and BEDC is calculated.
To run a block test on a virtual path connection VPC (OAM F4 PM), assign all the VCCs of the tested VPC
to the same performance monitoring table and follow the above PM initialization steps for each VCC. An
alternate method of implementing an OAM F4 test is to use the address compression mechanism to assign
the same channel number to a certain VPI by masking out the VCI field in the VPC header. This channel
can then be configured for PM and assigned a PM table.
Each time the transmit cell counter (TCC) in the performance monitoring table reaches the PM block size
(BLCKSIZE), the CP generates an FMC. The CP copies the FMC header, MCSN, TUC
0+1
, TUC0,
BEDC
0+1
-Tx from the PM table and places them in the FMC template. The time stamp (TSTP) is read
from the memory address specified by FMCTIMESTMP in the parameter RAM (see Table 39-2 ). The CP
then inserts the FMC into the user cell stream.
A TUC is a free-running counter (modulo 65,536) that counts transmitted user cells. The total number of
transmitted cells of a particular block is the difference between the TUC values in two consecutive FMCs.
The BEDC (BIP-16) calculation is done on the payload of all user cells of the current tested block. The
PM block size can be a multiple of 128 bytes up to 32Kbytes.
TSTP Time stamp. Used to indicate when the cell was inserted. Yes Yes
BEDC
0+1
Block error detection code. Even parity over the payload of the block of user cells sent
since the last FMC. No Yes
TRCC
0
Total received cell count 0. Counts CLP=0 user cells (modulo 65,536) received before the
FMC was received. Yes No
BLER Block error result. Counts error parity bits detected by the BEDC of the received FMC. Yes No
TRCC
0+1
Total received cell count 0+1. Counts all user cells (modulo 65,536) received before the
FMC was received. Yes No
Table 39-2. Performance Monitoring Cell Fields (continued)
Field Description BRC FMC