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
Rear Transition Module Motherboard (RTMM)
RTMM2 | RTMM1 | RTMM0 | |
RTMMv1 | Open | Open | GND |
RTMMv2 | Open | GND | Open |
Reserved | Open | GND | GND |
Reserved | GND | Open | Open |
Reserved | GND | Open | GND |
Reserved | GND | GND | Open |
Reserved | GND | GND | GND |
Error | Open | Open | Open |
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 | |
Error or Blocking/RS-485 V1 | Open | Open | Open |
Blocking V2 | Open | Open | GND |
RS-485 V2 | Open | GND | Open |
Reserved | Open | GND | GND |
Reserved | GND | Open | Open |
Reserved | GND | Open | GND |
Reserved | GND | GND | Open |
For an explanation of line 1, 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*.