IBM MCGA
About the IBM MCGA PCB
IBM MCGA is an open source PCB design by schlae, published on GitHub. It is a board, with 819 components from 106 distinct parts.
Other key parts include the INV, AND3, DFFAR, NAND and DFFAP. By type, the board carries 762 ICs and 57 connectors.
From the project
IBM MCGA reverse engineered chips
IBM's MCGA (Multi-Color Graphics Array) is a low-cost video chipset introduced with the PS/2 models 25 and 30. The Epson Equity 1e uses MCGA compatible video but does not use the same chips.
The IBM chipset consists of the memory controller gate array and the video formatter gate array. Some examples of these were fabricated on an internal IBM gate array process, while others used an external gate array part by Seiko.
Main components on the IBM MCGA
IBM MCGA bill of materials (BOM)
819 components, 106 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 123 | INV | BC1_2 | U1, U5, U19, U21, U50, U79, U97, U109 +115 |
| 61 | AND3 | BC2_4 | U2, U3, U22, U33, U35, U36, U42, U45 +53 |
| 26 | DFFAR | DFFAR | U4, U76, U264, U271, U282, U352, U458, U459 +18 |
| 60 | NAND | BC1_3 | U6, U16, U27, U28, U74, U90, U96, U98 +52 |
| 12 | DFFAP | DFFAP | U7, U9, U13, U15, U24, U47, U48, U53 +4 |
| 15 | BUF | BC1_2 | U8, U25, U72, U151, U198, U199, U236, U237 +7 |
| 34 | NOR | BC1_3 | U10, U11, U14, U17, U20, U23, U55, U61 +26 |
| 37 | INVP | BC1_2 | U12, U58, U78, U87, U132, U133, U136, U141 +29 |
| 37 | NAND3 | BC2_4A | U18, U73, U85, U89, U95, U99, U114, U115 +29 |
| 17 | OR3 | BC2_4 | U26, U56, U94, U104, U110, U168, U224, U305 +9 |
| 4 | BUFPP | BC3_2 | U29, U30, U149, U238 |
| 24 | XOR | BC3_3 | U31, U32, U34, U37, U43, U44, U46, U128 +16 |
| 24 | FA1 | BC9_5 | U38, U39, U40, U41, U62, U63, U64, U65 +16 |
| 18 | DFFMS | DFFMS | U51, U71, U83, U88, U425, U490, U508, U509 +10 |
| 4 | AOI23 | BC2_4A | U52, U54, U77, U80 |
| 8 | NOR4 | BC2_5 | U57, U182, U184, U417, U479, U641, U642, U645 |
| 1 | FF4AC | FF4AC28 | U59 |
| 15 | MUX21_4 | MUX21_4 | U68, U218, U251, U267, U268, U338, U340, U374 +7 |
| 18 | INVP4 | BC2_2 | U75, U227, U228, U470, U525, U526, U600, U607 +10 |
| 11 | COUNT4 | COUNT4 | U84, U93, U120, U335, U343, U378, U418, U551 +3 |
Show 86 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 8 | COMP8 | COMP8 | U91, U92, U127, U312, U385, U399, U454, U559 |
| 13 | NAND4 | BC2_5 | U105, U108, U181, U185, U638, U639, U640, U644 +5 |
| 3 | MAG4 | MAG4 | U125, U401, U496 |
| 1 | OA23 | BC2_4 | U144 |
| 10 | AND5 | BC3_6 | U150, U259, U299, U310, U377, U445, U494, U546 +2 |
| 3 | MUX21_8 | MUX21_8 | U152, U153, U156 |
| 48 | AOI48 | BC4_9 | U154, U155, U206, U207, U208, U210, U212, U213 +40 |
| 7 | SRFAP | BC9_6 | U164, U273, U497, U573, U584, U596, U598 |
| 14 | LATCH8 | LATCH8 | U175, U176, U178, U216, U303, U313, U334, U336 +6 |
| 3 | OR5 | BC3_6 | U179, U424, U727 |
| 9 | NOR3 | BC2_4A | U180, U274, U276, U281, U292, U294, U416, U493 +1 |
| 2 | NOR5 | BC3_6A | U186, U187 |
| 6 | DECODER38 | DECODER38 | U188, U204, U265, U349, U350, U359 |
| 2 | MUX21_4S | MUX21_4S | U220, U341 |
| 2 | FF4L | FF4L | U221, U342 |
| 9 | AOI24 | BC2_5 | U222, U242, U272, U283, U322, U409, U410, U558 +1 |
| 6 | AO23 | BC2_4 | U239, U477, U498, U506, U507, U515 |
| 27 | XNOR | BC3_3 | U255, U258, U260, U262, U297, U298, U300, U320 +19 |
| 3 | FF8 | FF8 | U266, U398, U402 |
| 5 | FF4P | FF4P | U301, U444, U484, U522, U674 |
| 3 | FF4A | DFF4A | U347, U676, U718 |
| 3 | INCMUX4 | INCMUX4 | U348, U675, U717 |
| 2 | FF4C | FF4C | U360, U716 |
| 18 | LATCH | LATCH | U406, U407, U414, U481, U520, U557, U560, U561 +10 |
| 1 | OAI26 | BC3_7 | U457 |
| 2 | FF4AC28 | FF4AC28 | U464, U754 |
| 1 | SR8SIPO | SR8SIPO | U489 |
| 1 | OAI24 | BC2_5 | U672 |
| 1 | NAND5 | BC3_6A | U752 |
| 1 | F_SYNC | PADO_1 | J3 |
| 1 | V CAS | PADO_1 | J4 |
| 1 | V MOE# | PADO_1 | J5 |
| 1 | V_MWE | PADO_1 | J6 |
| 1 | V_MSC | PADO_1 | J7 |
| 1 | FR | PADO_1 | J8 |
| 1 | VM R | PADI_1 | J9 |
| 1 | VM W | PADI_1 | J10 |
| 1 | V RAS | PADO_1 | J11 |
| 1 | VI_W# | PADI_1 | J12 |
| 1 | VI_R# | PADI_1 | J13 |
| 1 | VSYNC | PADO_1 | J14 |
| 1 | F_CURS | PADO_1 | J15 |
| 1 | UNK | PADO_1 | J16 |
| 1 | F_CLK1 | PADO_1 | J19 |
| 1 | F_CLK0 | PADO_1 | J20 |
| 1 | SD3 | PADI_1 | J21 |
| 1 | CGCLK | PADO_1 | J22 |
| 1 | FG | PADO_1 | J23 |
| 1 | CGA12 | PADO_1 | J24 |
| 1 | CG_CS | PADO_1 | J25 |
| 1 | CGA3 | PADO_1 | J27 |
| 1 | CGA2 | PADO_1 | J28 |
| 1 | CGA1 | PADO_1 | J29 |
| 1 | CGA0 | PADO_1 | J30 |
| 1 | CGOE | PADO_1 | J31 |
| 1 | CGWE | PADO_1 | J32 |
| 1 | VCKIN | PADI_1 | J33 |
| 1 | 25MHz | PADI_1 | J34 |
| 1 | VCK | PADO_1 | J37 |
| 1 | PADO | PADO_1 | J38 |
| 1 | MUXG | PADO_1 | J39 |
| 1 | MUXSEL | PADO_1 | J40 |
| 1 | H_SYNC | PADO_1 | J41 |
| 1 | A3 | PADI_1 | J42 |
| 1 | A0 | PADI_1 | J43 |
| 1 | V_EXT | PADI_1 | J44 |
| 1 | CD7 | PADIO_2 | J45 |
| 1 | CD6 | PADIO_2 | J46 |
| 1 | CD5 | PADIO_2 | J47 |
| 1 | CD4 | PADIO_2 | J48 |
| 1 | CD3 | PADIO_2 | J49 |
| 1 | CD2 | PADIO_2 | J50 |
| 1 | 14MHz | PADI_1 | J53 |
| 1 | CD1 | PADIO_2 | J54 |
| 1 | CD0 | PADIO_2 | J55 |
| 1 | IRQ2 | PADO_2 | J56 |
| 1 | RDY# | PADO_2 | J57 |
| 1 | H_EXT | PADI_1 | J58 |
| 1 | VMA7 | PADO_1 | J61 |
| 1 | VMA6 | PADO_1 | J62 |
| 1 | VMA5 | PADO_1 | J63 |
| 1 | VMA4 | PADO_1 | J64 |
| 1 | VMA3 | PADO_1 | J65 |
| 1 | VMA2 | PADO_1 | J66 |
| 1 | VMA1 | PADO_1 | J67 |
| 1 | VMA0 | PADO_1 | J68 |
IBM MCGA design files
The KiCad project lives in the schlae/IBM_MCGA repository on GitHub; these links point at the commit this page was built from.
IBM MCGA: common questions
How many components are on the IBM MCGA?
819 components, from 106 distinct parts. The full bill of materials is listed on this page.
Where can I download the IBM MCGA design files?
From the schlae/IBM_MCGA repository on GitHub, which has the schematic; the links under Design files point to each one.
Can I use the IBM MCGA design in my own project?
The repository has no license, so all rights stay with schlae. Use it as a reference, and ask the author before reusing the design.