View source for MSV11-P MOS Random-Access Memory

[[Image:MSV11-P.jpg|thumb|250px|right|MSV11-PK card]]

The '''MSV11-P''' (M8067) is a [[DEC card form factor|quad]]-height [[QBUS]] [[Dynamic RAM|DRAM]] [[main memory]] card. The MSV11-PL (M8067-Lx) holds 512 KBytes when fully populated with 64K DRAMs  [[integrated circuit|chips]], the MSV11-PK (M8067-Kx) is half-populated (the only partially-filled configuration allowed) and holds 256 Kbytes. (The 'x' in the board identifier is a capital letter which identifies the manufacturer of the DRAM chips.)

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 can be configured as either a [[QBUS#Variable address size|Q18]] card, or a Q22 card; the -PL ''must'' be configured as a Q22 card due to its size. It can also be configured for use either in a [[QBUS#Backplanes|Q/CD backplane]] or a [[QBUS#Backplanes|Q/Q backplane]]. <!--; it reportedly supports QBUS block mode-->.

==Configuration==

The card is configured by [[jumper]]s on [[wire-wrap]] posts; it is possible to set:
* the starting address;
* the size (256KB or 512KB);
* the CSR address;
<!-- * parity enable;
* parity error action;
* bank disable. -->
* enable wrong parity.
<!-- {| class="wikitable"
! S1 || S2 || Staring Address
|-
| OFF || OFF || 00000000 (0 MB)
|-
| OFF || ON ||  04000000 (1 MB)
|-
| ON || OFF || 10000000 (2 MB)
|-
| ON || ON || 14000000 (3 MB)
|}

==Control Register==
Each board has a single control [[register]], which can be configured in the range 17772100-17772136.
{| class="wikitable"
! S5 !! S6 !! S7 !! S8 !! CSR Address
|-
| ON || ON || ON || ON || 17772100
|-
| ON || ON || ON || OFF || 17772102
|-
| ON || ON || OFF || ON || 17772104
|-
| ON || ON || OFF || OFF || 17772106
|-
| ON || OFF || ON || ON || 17772110
|-
| ON || OFF || ON || OFF || 17772112
|-
| ON || OFF || OFF || ON || 17772114
|-
| ON || OFF || OFF || OFF || 17772116
|-
| OFF || ON || ON || ON || 17772120
|-
| OFF || ON || ON || OFF || 17772122
|-
| OFF || ON || OFF || ON || 17772124
|-
| OFF || ON || OFF || OFF || 17772126
|-
| OFF || OFF || ON || ON || 17772130
|-
| OFF || OFF || ON || OFF || 17772132
|-
| OFF || OFF || OFF || ON || 17772134
|-
| OFF || OFF || OFF || OFF || 17772136
|}
In the register contents (below), all the bits can be read and written by [[software]]; most are cleared by power up and bus INIT. Bits which can only be modified by the CPU are shown in normal font, and those which can also be set by the [[hardware]] in ''italics''.
{{16bit-header}}
| ''Parity Error'' || Extended Error Address Enable || colspan=2 | Reserved || colspan=7 | ''Error Address'' || colspan=2 | Reserved || Write Wrong Parity || Reserved || Parity Error Enable 
{{16bitoctal-bitout}}
The 'Error Address' field contents depend on the setting of the 'Extended Error Address Enable' bit; when it holds the low address ('Extended Error Address Enable' is 0), it holds address bits 11 through 17; when it holds the high address ('Extended Error Address Enable' is 1), it holds bits 21 through 18 - bits 11-9 of the register are unused.

==Technical information==

<!-- ''Note:'' When a DRAM chip is removed, if the affected memory location is then read, that bit will be ''high'' (1), not ''low'' (0); the affected input (apparently separate pins for the low and high banks) must float to 1 when there is no DRAM chip present to drive the input.
The following 256K DRAM chips have been observed to be used: MB81256-15 (Fujitsu). M5K4164ANP-15P (Micron Technologies), NEC D4164C211 (NEC Electronics). HM50256-15 (Hitachi), TMS4256-15NL (Texas Instruments)
Note that some of these parts are 120 nsec parts, while others are 150 nsec; the faster parts do not seem to be necessary, or give any advantage. -->

==Further reading==

* ''Differences Between MSVI1-L and MSV11-P Memories'', [[MicroNote]] #111

==External links==

* [http://bitsavers.org/pdf/dec/qbus/EK-MSV0P-UG-001_MSV11P_Aug81.pdf MSV11-P User Guide] (EK-MSV0P-UG-001)
* [https://manx-docs.org/collections/hcps/msv11p.pdf MSV11-P Field Maintenance Print Set] (MP01239)

[[Category: QBUS Memories]]