MemoryVGAPmod
About the MemoryVGAPmod PCB
MemoryVGAPmod is an open source PCB design by mdrobot7, published on GitHub. It is a 4-layer board measuring 52.4 × 88.9 mm, with 46 components from 9 distinct parts.
Other key parts include the IS66WVQ16M4FBLL-200BLI and SN74ALVC245PWR. By type, the board carries 20 resistors, 14 capacitors, 5 ICs, 4 connectors and 3 inductors.
From the project
Mirror of the Chip Forge hardware repository, containing hardware for the uGPU senior design project. Mirror of https://git.ece.iastate.edu/isu-chip-fab/hardware
We need a DAC to convert our 8 bit pixels (3 bits red, 3 green, 2 blue) to analog color signals. The method with the fewest components is a resistor network with one resistor per bit. You could use an R2R ladder (Digilent does it in their VGA PMOD), but that's more parts. We will eventually move this on-chip, so fewer parts is better.
To find the resistances, we set up the circuit as a resistor divider with one bit's resistor on top and the remaining resistors and the 75 ohm termination on the bottom. From there it's a simple system solve. $B_0$ is the LSB here and we're using 3.3V IO.
Main components on the MemoryVGAPmod
MemoryVGAPmod bill of materials (BOM)
46 components, 9 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 3 | IS66WVQ16M4FBLL-200BLI | IS66WVQ16M4FBLL-200BLI | U1, U2, U3 |
| 2 | SN74ALVC245PWR | TSSOP-20_4.4x6.5mm_P0.65mm | U5, U6 |
| 4 | PMOD_Male | PMOD_Male | J1, J2, J3, J4 |
| 3 | 220R | L_0805_2012Metric_Pad1.05x1.20mm_HandSolder | FB1, FB2, FB3 |
| 3 | CL21A106KAYNNNE 10uF | C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C1, C5, C9 |
| 11 | CL21B104KBCNNNC 100nF | C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C2, C3, C4, C6, C7, C8, C10, C11 +3 |
| 3 | 10k | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1, R2, R3 |
| 14 | 487 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R4, R5, R6, R7, R8, R9, R10, R11 +6 |
| 3 | 422 | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R18, R19, R20 |
MemoryVGAPmod design files
The KiCad project lives in the mdrobot7/senior-design-hardware repository on GitHub; these links point at the commit this page was built from.
MemoryVGAPmod: common questions
How big is the MemoryVGAPmod PCB?
The MemoryVGAPmod measures 52.4 × 88.9 mm, has 4 copper layers and is 1.6 mm thick.
How many components are on the MemoryVGAPmod?
46 components, from 9 distinct parts. The full bill of materials is listed on this page.
Where can I download the MemoryVGAPmod design files?
From the mdrobot7/senior-design-hardware repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the MemoryVGAPmod design in my own project?
The repository has no license, so all rights stay with mdrobot7. Use it as a reference, and ask the author before reusing the design.
