Difference between revisions of "BM873 ROM"
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| − | The '''BM873 [[Read-only memory|ROM]]''' card was a [[UNIBUS]] card for the [[PDP-11]] series of computers; it was a [[DEC card form factor|quad]] format card, and contained 256 words of memory (optionally limited to 128 words). | + | The '''BM873 [[Read-only memory|ROM]]''' card was a [[UNIBUS]] card for the [[PDP-11]] series of computers; it was a [[DEC card form factor|quad]] format card, and contained 256 words of memory (optionally limited to 128 words), contained in four [[PROM]] chips (two, when the limitation option was selected). |
The board appeared at addresses from 773000 to 773776; if the 128-word limitation is enabled, the top address is 773376. Several of the computers it was intended for use with ([[PDP-11/40]], [[PDP-11/45]]) could be configured so that the host computer jumped to the code on the board on power-on. | The board appeared at addresses from 773000 to 773776; if the 128-word limitation is enabled, the top address is 773376. Several of the computers it was intended for use with ([[PDP-11/40]], [[PDP-11/45]]) could be configured so that the host computer jumped to the code on the board on power-on. | ||
| − | In addition, an edge connector provided four wires, each of | + | In addition, an edge connector provided four input wires, each of which (when puilled low) forced (via a simulated power-fail restart, and forcing the first two read cyles after the power-up to go to the board) the computer to jump to a particular address (configured by a group of 8 diodes, four groups in total) within the card's address space. |
| − | Most versions were used for [[bootstrapping]] the machine, from [[disk]], paper and magnetic tape, etc, but it could be | + | Most versions were used for [[bootstrapping]] the machine, from [[disk]], paper and magnetic tape, etc, but it could be used for any purpose. |
| − | + | In addition to an un-programmed variant, which the user could program as they wanted, the board came from DEC in several pre-programmed variants, designated BM792-Yx (where 'x' is a capital letter, starting with 'A'), set up to perform various functions. Many of the later variants were used to boot the PDP-11/40 used as the front-end processor in the [[KL10]]. | |
==Variants== | ==Variants== | ||
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* BM873-YB - As above, with the addition of RS0x and RP0x disks and TU16 tapes; in addition, booting from units other than 0 (with the unit being specified in the console switch register) | * BM873-YB - As above, with the addition of RS0x and RP0x disks and TU16 tapes; in addition, booting from units other than 0 (with the unit being specified in the console switch register) | ||
* BM873-YC - As the -YA variant, with added support for the [[DU11]] synchronous line interface | * BM873-YC - As the -YA variant, with added support for the [[DU11]] synchronous line interface | ||
| − | * BM873-YD - 1080 console | + | * BM873-YD - 1080 console; supported booting from, and dumping to, TC11, RP0x, and [[DTE20]] 10/11 interface |
* BM873-YE - Unknown | * BM873-YE - Unknown | ||
| − | * BM873-YF - 2040 console | + | * BM873-YF - 2040 console; same capabilities as -YD, except the [[RX11]] replaced the TC11 |
| − | * BM873-YG - DN87 communications | + | * BM873-YG - DN87 communications; supported booting from a [[DL11]] and the DTE20, and dumping to the latter |
| − | * BM873-YH - 10xx/20xx console | + | * BM873-YH - 10xx/20xx console; supported booting from TC11, RX11, RP0x, and possibly the DTE20 10/11 interface (the documenation is contradictory) |
| − | * BM873-YJ - 10xx/20xx console/communications | + | * BM873-YJ - 10xx/20xx console/communications; supported booting from TC11, RX11, RP0x, DL11 and the DTE20, and dumping to the latter |
==See also== | ==See also== | ||
Revision as of 15:48, 27 March 2016
The BM873 ROM card was a UNIBUS card for the PDP-11 series of computers; it was a quad format card, and contained 256 words of memory (optionally limited to 128 words), contained in four PROM chips (two, when the limitation option was selected).
The board appeared at addresses from 773000 to 773776; if the 128-word limitation is enabled, the top address is 773376. Several of the computers it was intended for use with (PDP-11/40, PDP-11/45) could be configured so that the host computer jumped to the code on the board on power-on.
In addition, an edge connector provided four input wires, each of which (when puilled low) forced (via a simulated power-fail restart, and forcing the first two read cyles after the power-up to go to the board) the computer to jump to a particular address (configured by a group of 8 diodes, four groups in total) within the card's address space.
Most versions were used for bootstrapping the machine, from disk, paper and magnetic tape, etc, but it could be used for any purpose.
In addition to an un-programmed variant, which the user could program as they wanted, the board came from DEC in several pre-programmed variants, designated BM792-Yx (where 'x' is a capital letter, starting with 'A'), set up to perform various functions. Many of the later variants were used to boot the PDP-11/40 used as the front-end processor in the KL10.
Variants
- BM873-YA - Boot from disks (RF11, RK11, RP11, RC11), TC11 DECtape, TM11 magnetic tape, TA11 casette magnetic tape, serial line, and high-speed paper tape reader
- BM873-YB - As above, with the addition of RS0x and RP0x disks and TU16 tapes; in addition, booting from units other than 0 (with the unit being specified in the console switch register)
- BM873-YC - As the -YA variant, with added support for the DU11 synchronous line interface
- BM873-YD - 1080 console; supported booting from, and dumping to, TC11, RP0x, and DTE20 10/11 interface
- BM873-YE - Unknown
- BM873-YF - 2040 console; same capabilities as -YD, except the RX11 replaced the TC11
- BM873-YG - DN87 communications; supported booting from a DL11 and the DTE20, and dumping to the latter
- BM873-YH - 10xx/20xx console; supported booting from TC11, RX11, RP0x, and possibly the DTE20 10/11 interface (the documenation is contradictory)
- BM873-YJ - 10xx/20xx console/communications; supported booting from TC11, RX11, RP0x, DL11 and the DTE20, and dumping to the latter
See also
Reference
- EK-BM873-TM-004, BM873 restart/loader
- KL873.MEM, KL10 BM873 Bootstrap ROMs
