Dual Port Memory (DPM)

There are 8 Dual Port Memory (DPM) modules in the OD DAQ VME crate. They are MM6390/32 models, made by Micro Memory Inc. with 32 MByte capacity each.

Two DPMs are used each for storing data from one of the 4 outer electronics huts. The data is received by a DC2/DM115 module and saved in one of the two DPMs in "ping-pong" mode, whereas the second DPM can be accessed by the Bit3 module via the VMEbus which then transfers its content to the OD online workstation (sukant).

ping-pong diagram

OD-DAQ VME slots and addresses

(see also the OD-DAQ custom electronics overview)

VME slotaddress rangefunction
140x08000000 ... 0x09FFFFFFDPM A for hut 1 data
150x0B000000 ... 0x0CFFFFFFDPM B for hut 1 data
160x0E000000 ... 0x0FFFFFFFDPM A for hut 2 data
170x11000000 ... 0x12FFFFFFDPM B for hut 2 data
180x04000000 ... 0x15FFFFFFDPM A for hut 3 data
190x17000000 ... 0x18FFFFFFDPM B for hut 3 data
200x1A000000 ... 0x1BFFFFFFDPM A for hut 4 data
210x1D000000 ... 0x1EFFFFFFDPM B for hut 4 data

Important note:

The DPM modules are shipped from the factory with jumper E7 enabled. This jumper sets "Enable A24 Adressing". For the OD DAQ system this jumper MUST be removed. Failure to do so will mean the DPMs will respond to any access to the V533 modules in A24 mode.

The DPMs should be accessed in A32 mode ONLY to avoid address conflicts.

HGB, last edited 06/23/01.