The MP-B2 Mother Board is a 9 " x 14" double sided plated thru hole board onto which all of the various processor boards are plugged. Provisions have been made for one processor board, up to four memory boards plus two unused slots. This gives the user the ability to handle up to 32K words of memory. The mother board also provides the line buffering and address decoding for up to eight interface boards. Although one of the eight must be the serial control interface, the other seven may be any combination of serial (MP-S) and parallel (MP-L) interfaces the user may choose to have.
From the Assembly Instructions:
The original MP-B Mother Board decoded the entire 8 K block of memory from 32K thru 40K as being resident on the mother board. Although simpler from a circuitry viewpoint, this technique was wasteful and has been changed on this version, the MP-B2, so that only the 32K thru 36K block has been allocated to the mother board interface addresses. This allows boards outside the interface address range to use the 36K thru 40K memory addresses. The new decoding arrangement also makes it easy to reassign the interface address block to any 4K region from 32K to 64K in 4K increments. Although this isn't allowable when using the MIKBUG® or SWTBUG® monitors, it does have potential when using custom monitors.
MP-B2 Mother Board Assembly Instructions (52k PDF)
MP-B2 Mother Board Schematic (136k JPG)
MP-B2 Mother Board Red Blue Layout (150k JPG)
Michael Holley's SWTPC Collection Home Page
This page was last edited August 05, 2014