Hol-1 Memory Management Unit
About the Hol-1 Memory Management Unit PCB
Hol-1 Memory Management Unit is an open source PCB design by agben, published on GitHub. It is a 2-layer board measuring 106.7 × 76.2 mm, with 37 components from 20 distinct parts.
Other key parts include the 74LS00, 74LS173 and 74LS157. By type, the board carries 8 ICs, 8 capacitors, 6 switches, 5 connectors, 3 jumpers and 3 resistors.
From the project
Homebrew 8-bit TTL CPU
HOL-1 a homebrew 8-bit TTL CPU --- HOL-1 is a TTL based 8-bit CPU based on the 'simple as possible' breadboard design by Ben Eater https://eater.net/8bit/
As well as adding my own modifications to each module of this CPU. i.e. - more memory - more registers - more ALU functions - more commands (assembler code to follow)
The main change is that HOL-1 is designed for permanent construction using common 8cm x 12cm double-sided perfboards.
Main components on the Hol-1 Memory Management Unit
Hol-1 Memory Management Unit bill of materials (BOM)
37 components, 20 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | 74LS00 | DIP-14 | U1 |
| 2 | 74LS173 | DIP-16 | U2, U4 |
| 5 | 74LS157 | DIP-16 | U3, U5, U6, U7, U8 |
| 1 | DATA BUS | IDC_head_8x2 | P1 |
| 1 | ADDRESS PORT | IDC_head_4x2 | P2 |
| 1 | DATA PORT | IDC_head_4x2 | P3 |
| 1 | MMU CONTROL | IDC_head_4x2 | P4 |
| 1 | Power | JST_head_2X1 | P5 |
| 2 | Blinken hex lights | SIL-10 | JP1, JP2 |
| 1 | Blinkenlights | SIL-9 | JP3 |
| 2 | 220Ω | r_pack8 | RA1, RA2 |
| 4 | HEX_SWITCH | SW_Hex6 | SW1, SW2, SW3, SW4 |
| 1 | DPDT | sw-dpdt-push | SW5 |
| 1 | SW_PUSH | sw_push_lrg | SW6 |
| 2 | LED | LED-5MM | D1, D2 |
| 1 | 0.01uF | C1 | C1 |
| 6 | 100nF | C1 | C2, C4, C5, C6, C7, C8 |
| 1 | 100nF | C2 | C3 |
| 2 | 220Ω | R4 | R1, R3 |
| 1 | 1K | R4 | R2 |
Hol-1 Memory Management Unit design files
The KiCad project lives in the agben/Hol-1 repository on GitHub; these links point at the commit this page was built from.
- LayoutMMU/Hol-1-MMU.kicad_pcb
- SchematicMMU/Hol-1-MMU.kicad_sch
Hol-1 Memory Management Unit: common questions
How big is the Hol-1 Memory Management Unit PCB?
The Hol-1 Memory Management Unit measures 106.7 × 76.2 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Hol-1 Memory Management Unit?
37 components, from 20 distinct parts. The full bill of materials is listed on this page.
Where can I download the Hol-1 Memory Management Unit design files?
From the agben/Hol-1 repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the Hol-1 Memory Management Unit design in my own project?
The repository has no license, so all rights stay with agben. Use it as a reference, and ask the author before reusing the design.
