Rear Transition Module detection
It is important to detect which rear boards are connected. Six pins are committed to this feature: three pins for the rear transition module motherboard (RTMM) and three pins for the rear-transition module piggyback (RTMP) board.
Board Detection
The board detection works in the same way as VME64x Geographical Address pins, in which every pin is open by default and grounded while asserted. The open pin is connected to VCC via pull-up resistors on the front module board, and then through inverting Schmitt triggers to the FPGA inputs. Thus, when the FPGA detects a high level it indicates that a certain pin was asserted, and that an RTMM/P is present.
Board Classification Pins
The tables below show the connection of the detection lines on the RTMM and RTMP boards.
Rear Transition Module Motherboard (RTMM)
RTMM2 | RTMM1 | RTMM0 | |
---|---|---|---|
Not connected | Open | Open | Open |
RTMM | Open | Open | GND |
Reserved | Open | GND | Open |
Reserved | Open | GND | GND |
Reserved | GND | Open | Open |
Reserved | GND | Open | GND |
Reserved | GND | GND | Open |
Reserved | GND | GND | GND |
Note*: Due to reasons specified above, in the context of the FPGA firmware, an Open should be read as GND, and a GND as VCC*.
Rear Transition Module Panel (RTMP)
RTMP2 | RTMP1 | RTMP0 | |
---|---|---|---|
Blocking | Open | Open | Open |
RS-485 | Open | Open | GND |
Blocking V2 | Open | GND | Open |
Reserved | Open | GND | GND |
Reserved | GND | Open | Open |
Reserved | GND | Open | GND |
Reserved | GND | GND | Open |
For an explanation about the selection of Blocking RTMP identification
lines, see issue #702.
Note*: Due to reasons specified above, in the context of the FPGA
firmware, an Open should be read as GND, and a GND as
VCC*.
Theodor-Adrian Stana, Carlos-Gil Soriano, Jul. 2014