1. RCE Application Workshop
PGP Loopback Example
8/1/16
RCE Application Workshop

2. RCE Application Workshop
PGP Example Essence
Internal or external data loopback transmission test
Mode=1,2 internal loopback of TX<->RX of same channel
Mode=0 external DMA via RTM I/O channel.
Only works on the COB DPM/DTM at the moment.
8/1/16
RCE Application Workshop

3. RCE Application Workshop
Firmware and Software
Code instructions at:
ATLAS wrapped release from CERN git reposity
SLAC Lab1 local setup of hardware and Vivado:
CobPgpFirmware may take ~2 hours for first build. Probably better to take pre-built fpga.bit and explore the PgpSoftware part first.
Original SLAC local version of ExampleRCEProject from Larry is documented at:
including register address space info.
8/1/16
RCE Application Workshop

4. SLAC Lab1 Hardware Setup
Fully populated COB residing in the 6-slot shelf ‘cscnrc’ slot-2 with 16xSFP RTM at the back
Each of the 8 RCEs on DPMs has 12 user I/O lanes but only two of them (Ch0,Ch6) are connected to the 16 SFP RTM.
CSC RTMs
16xSFP RTM
RTM RCE-channel order within
a Bay: 2-6, 0-6, 2-0, 0-0
Bay 3
Bay 0
Node
Bay
RCE
rce00
rce20 2
rce02
rce22
rce10 1
rce30 3
rce12
rce32
dtm1 4
RCEs 00,10,20:
RTM Ch0-Ch6 are externally linked with duplex fibers
Other RCE I/O channels are self-terminated
8/1/16
RCE Application Workshop

5. rateTest Control Parameters
Example test modes:
rateTest -l 2 -s 0 -r 0 # internal firmware PGP loopback on lane 0
rateTest -l 0 -s 0 -r 0 # loop back through SFP port holding a loopback terminator
rateTest -l 0 -s 0 -r 6 # COB/DPM transceiver loopback from lane 0 to 6 by fiber
The set of control arguments for rateTest:
Arguement
Description
Default
-m dataSize
data packet size for each inner loop transmission, in bytes
0x400 (1024)
-v virtualChannel
virtual channel number
-l loopback
Loopback mode 0=external; 2=internal
-s senderLane
sender RCE user I/O channel (0-11). 16-SFP RTM can only take 0 or 6
-r recvLane
receiver RCE user I/O channel (0-11)
8/1/16
RCE Application Workshop

6. Improvement/Exercise
Add code to record transaction time stamps to allow proper data rate calculation.
Check data rate performance vs packet size and between internal and external data transmissions.
Add code to create real payload data and check for bit errors after repeated loops of sending received pattern to next loop. How much slow down is observed from doing this ?
Histogram transaction time variations.
8/1/16
RCE Application Workshop