TMS9918A
About the TMS9918A PCB
TMS9918A is an open source PCB design by jblang, published on GitHub. It is a 2-layer board measuring 99.1 × 49.9 mm, with 36 components from 25 distinct parts.
Other key parts include the 74HCT32, 74LS138, TMS9918A, 74HCT04 and 74HCT574. By type, the board carries 11 capacitors, 8 ICs, 7 connectors, 3 jumpers, 3 resistors and 1 transistor.
It belongs with the retro computing designs in this gallery.
From the project
TMS9918A video card for RC2014
This is a TMS9918A-based video card for RC2014 and SC1xx computers based on the Z80 and Z180 processors. The TMS9918A produces NTSC composite graphics and was used in the TI-99/4A, MSX, ColecoVision, and Sega SG-1000. Enhanced derivatives were used in later MSX2 computers, the Sega Master System, and the Sega Genesis.
This board is based on a circuit described by Tom LeMense for interfacing the TMS9918A with SRAM. I started with his schematics, added port address decoding and laid out the circuit on an RC2014 module.
Main components on the TMS9918A
TMS9918A bill of materials (BOM)
36 components, 25 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | 74HCT32 | DIP-14_W7.62mm_Socket | U1 |
| 1 | 74LS138 | DIP-16_W7.62mm_Socket | U2 |
| 1 | TMS9918A | DIP-40_W15.24mm_Socket | U3 |
| 1 | 74HCT04 | DIP-14_W7.62mm_Socket | U4 |
| 3 | 74HCT574 | DIP-20_W7.62mm_Socket | U5, U6, U7 |
| 1 | HM62256BLP-7 | DIP-28_W15.24mm_Socket | U8 |
| 1 | 2N4401 | TO-92 | Q1 |
| 1 | 10.738635MHz | Crystal_HC49-4H_Vertical | Y1 |
| 1 | Conn_01x39 | PinHeader_1x39_P2.54mm_Vertical | J1 |
| 1 | Conn_Coaxial | KLPX-0848A | J2 |
| 1 | Conn_01x14 | PinHeader_1x14_P2.54mm_Vertical | J3 |
| 1 | Conn_02x08_Odd_Even | PinHeader_2x08_P2.54mm_Vertical | J4 |
| 1 | Conn_01x10 | PinHeader_1x10_P2.54mm_Vertical | J5 |
| 1 | A4 | PinHeader_2x03_P2.54mm_Vertical | J6 |
| 1 | Ext | PinHeader_1x05_P2.54mm_Vertical | J7 |
| 1 | A1/A2 | PinHeader_1x03_P2.54mm_Vertical | JP1 |
| 1 | A3 | PinHeader_1x03_P2.54mm_Vertical | JP2 |
| 1 | Jumper_NC_Dual | PinHeader_1x03_P2.54mm_Vertical | JP4 |
| 1 | 1N4148 | D_DO-35_SOD27_P7.62mm_Horizontal | D1 |
| 1 | Ferrite_Bead | R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | L1 |
Show 5 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 2 | 16pf | C_Disc_D3.0mm_W1.6mm_P2.50mm | C1, C2 |
| 9 | 0.1uf | C_Disc_D3.0mm_W1.6mm_P2.50mm | C3, C4, C5, C6, C7, C8, C9, C10 +1 |
| 1 | 75 | R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R1 |
| 1 | 0 | R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R2 |
| 1 | 470 | R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R3 |
TMS9918A design files
The KiCad project lives in the jblang/TMS9918A repository on GitHub; these links point at the commit this page was built from.
- LayoutTMS9918.kicad_pcb
- SchematicTMS9918.kicad_sch
TMS9918A: common questions
How big is the TMS9918A PCB?
The TMS9918A measures 99.1 × 49.9 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the TMS9918A?
36 components, from 25 distinct parts. The full bill of materials is listed on this page.
Where can I download the TMS9918A design files?
From the jblang/TMS9918A repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the TMS9918A design in my own project?
The repository has no license, so all rights stay with jblang. Use it as a reference, and ask the author before reusing the design.
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