VIC Setup

Before using the VIC8250/8251 you have to setup the switches, the jumpers and so on. This brief guide reflects our experience in setting up the VIC and should help non-experienced users.

1. Front Board Switches

There are two switches on the front board of VIC8250. one is a dip switch and the other is a rotary switch. The VME chain can be up to 100 meters long and can connect up to 15 crates. The rotary switch is used to set the crate number(1-f).

If the VIC is the master controller of the VME chain bit 2 and bit 4 of the dip switch should be set open ('right' from the front view). If the VIC is used as one of the slave crates controller only bit 5 of the dip switch has to be set open. Please look at figure as following:

  +---+                         +---+ 
  |o  |sw1                      |o  |sw1 
  |  o|sw2                      |o  |sw2 
  |o  |sw3                      |o  |sw3 
  |  o|sw4                      |o  |sw4 
  |o  |sw5                      |  o|sw5 
  |o  |sw6                      |o  |sw6 
  +---+                         +---+ 
  Master                        Slave

The other rotary switch is located between the P1 and P2 connectors on the VIC board. This switch is used to set the base address of the VIC8250 CSR space. The VIC8250 CSR space allows us to map the different resources in VME and/or VSB. The CSR space is mapped onto 1 Mbyte in the VME standard addressing space (defined by AM code =$39 and $3D) user data and supervisor data.

2. ARB8430 Jumpers

ARB8430 is the arbitration piggy-back of VME. There are two jumpers, w01 and w02, on it.

When jumper "w01" is plugged in, the functions performed by the piggy-back are enabled. When it is removed, they are disabled.

The jumper labeled "w02" allows us to mask the generation of VME SYSRESET. If this jumper is removed, the VIC8250's VMV Slave port can not generate a VME SYSRESET.

If the VIC is the master controller, jumper "w01" on the arbitration piggy-back should be removed. If the VIC8250 is the slave crate controller both jumpers have to be plugged in.

3. Terminators

The TER8560 is a piggy-back board of the VIC8250/8251 used to terminate the VMVbus electrically. The VMVbus must be terminated correctly at both ends of the chain. But the terminator must be removed from the VIC board installed in the middle of the chain.

4. VMV Cables

The VMV signals are distributed over two twisted pair flat cables (60 wires). The use of twisted-pair cables with impedance close to 110 Ohm is necessary in order to ensure correct transmission of VMV signals over the cables and to minimize cross-talk.

5. Broadcast Registers

There is a known problem with the broadcast registers on VIC8250. For long chains the results of these registers might be incorrect. Since a KLOE chain is not really long we should not have trouble with that.

6. Remote Data Access

The cycle generation on the external VME crates is done transparently after initialization of the VIC8250. In VMV systems, all VMEs are independent. When a CPU located in a master crate accesses a remote slave crate, the two VME busses are linked during the cycles. Between the two mapped crates the VME address must be aligned to 1 MB/ VIC8250 (or 4 MB/VIC8251) page boundary. To map more than 1 (or 4) MB, additional VIC pages must be programmed.

Please, send comments to Mei Wen (meiwen@lnf.infn.it)