MSV11-M QBUS memory

MSV11-MB card

The MSV11-M (M7506) is a dual-height QBUS DRAM main memory card. The MSV11-MB (M7506-BA) holds 1 MByte when fully populated with 256K DRAMs chips, the MSV11-MA (M7506-AA) is half-populated (the only partially-filled configuration allowed) and holds 512 Kbytes.

The memory is arranged as 2 banks, each 16 data bits (1 PDP-11 word) wide, with 2 additional bits for parity (1 per byte). It is a Q22 card; it reportedly supports QBUS block mode.

Configuration

No documentation on the MSV11-M is extant, so it is currently not known how to configure it. The purpose of the two-position jumper between E19 (apparently a delay line) and E18 is currently unknown.

Control Register

Each board has a single control register, which can be configured in the range 17772100-17772136, using the set of four jumpers between chips E27 and E26. They are not numbered on the board; for our purposes we will number them W1-W4, starting with the left-hand jumper, with the board oriented with the insertion handles at the top.

W4	W3	W2	W1	CSR Address
In	In	In	In	17772100
In	In	In	Out	17772102
In	In	Out	In	17772104
In	In	Out	Out	17772106
In	Out	In	In	17772110
In	Out	In	Out	17772112
In	Out	Out	In	17772114
In	Out	Out	Out	17772116
Out	In	In	In	17772120
Out	In	In	Out	17772122
Out	In	Out	In	17772124
Out	In	Out	Out	17772126
Out	Out	In	In	17772130
Out	Out	In	Out	17772132
Out	Out	Out	In	17772134
Out	Out	Out	Out	17772136

Technical information

As far as is known, there are no copies of the engineering drawings extant for the MSV11-M.

Further reading

• MSV11-M User Guide, EK-MSV1M-UG
• MSV11-M Field Maintenance Printset (MP-02053 - not online)