Main Board
About the Main Board
Main Board is an open source PCB design by juniperlynx, published on GitHub. It is a 2-layer board measuring 212 × 126 mm, with 75 components from 41 distinct parts.
Other key parts include the MC14500B, 74HC02, 74HC00, 74HC259 and 74HC251. By type, the board carries 20 capacitors, 18 resistors, 16 connectors, 15 ICs, 4 diodes and 1 fuse.
From the project
A trainer / demonstration system for the Motorola MC14500B
The Uno 14500 is a demonstration and training system built around the Motorola MC14500BCP Industrial Control Unit.
Its design borrows heavily from several sources including the Motorola ICU Handbook, Usagi Electric's MC14500 SBC, Nicola Cimmino's PLC14500, and my original Uno computer, a CMOS CPU I wire wrapped in college.
The system has 256 bytes of program memory, an 8 bit scratch register, an 8 bit output register, and an 8 bit input mux.
Main components on the Main Board
Main Board bill of materials (BOM)
75 components, 41 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | MC14500B | DIP-16_W7.62mm_Socket_LongPads | U1 |
| 3 | 74HC02 | DIP-14_W7.62mm_Socket_LongPads | U2, U13, U15 |
| 2 | 74HC00 | DIP-14_W7.62mm_Socket_LongPads | U3, U14 |
| 2 | 74HC259 | DIP-16_W7.62mm_Socket_LongPads | U4, U5 |
| 2 | 74HC251 | DIP-16_W7.62mm_Socket_LongPads | U6, U7 |
| 2 | 74HC193 | DIP-16_W7.62mm_Socket_LongPads | U9, U10 |
| 2 | 2101 | DIP-22_W10.16mm_Socket_LongPads | U11, U12 |
| 1 | L7805 | TO-220-3_Horizontal_TabDown | U16 |
| 1 | DATA SW | PinHeader_2x08_P2.54mm_Vertical | J1 |
| 1 | INPUT SW | PinHeader_2x08_P2.54mm_Vertical | J2 |
| 1 | HALT | PinHeader_1x02_P2.54mm_Vertical | J3 |
| 1 | CLK_SRC | PinHeader_1x03_P2.54mm_Vertical | J5 |
| 1 | EXT_MEM | IDC-Header_2x10_P2.54mm_Horizontal | J6 |
| 1 | LD_ADDR | PinHeader_1x02_P2.54mm_Vertical | J7 |
| 1 | I / O | IDC-Header_2x10_P2.54mm_Horizontal | J8 |
| 1 | PWR_IN | BarrelJack_Horizontal | J9 |
| 1 | LD_INST | PinHeader_1x02_P2.54mm_Vertical | J10 |
| 1 | DISP2 | IDC-Header_2x12_P2.54mm_Vertical | J11 |
| 1 | RESET | PinHeader_1x02_P2.54mm_Vertical | J12 |
| 1 | CONFIG | IDC-Header_2x05_P2.54mm_Horizontal | J13 |
Show 21 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | STEP | PinHeader_1x02_P2.54mm_Vertical | J14 |
| 1 | SPEED | PinHeader_1x02_P2.54mm_Vertical | J15 |
| 1 | RUN | PinHeader_1x02_P2.54mm_Vertical | J16 |
| 1 | DISP1 | IDC-Header_2x09_P2.54mm_Vertical | J17 |
| 1 | 750mA | Fuseholder_Clip-5x20mm_Eaton_1A5601-01_Inline_P20.80x6.76mm_D1.70mm_Horizontal | F1 |
| 1 | POWER | SW_SPDT_SW-R3-2B-C-5-13 | SW1 |
| 1 | 1N4004 | D_DO-41_SOD81_P10.16mm_Horizontal | D1 |
| 1 | 1N5404 | D_DO-201AE_P15.24mm_Horizontal | D2 |
| 1 | HALT | PinHeader_1x02_P2.54mm_Vertical | D3 |
| 1 | RUN | PinHeader_1x02_P2.54mm_Vertical | D4 |
| 14 | 0.1uF | C_Axial_L3.8mm_D2.6mm_P10.00mm_Horizontal | C1, C2, C3, C4, C5, C9, C10, C11 +6 |
| 1 | 100uF | CP_Radial_D5.0mm_P2.00mm | C6 |
| 3 | 4.7uF | C_Rect_L4.6mm_W3.0mm_P2.50mm_MKS02_FKP02 | C7, C8, C20 |
| 2 | 47nF | C_Axial_L3.8mm_D2.6mm_P10.00mm_Horizontal | C19, C21 |
| 8 | 10K | R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1, R2, R3, R4, R5, R6, R7, R12 |
| 1 | 15K | R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R8 |
| 1 | 1M | R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R9 |
| 1 | 150K | R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R10 |
| 3 | 1K | R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R11, R16, R17 |
| 2 | 47K | R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R18, R19 |
| 2 | 10K | R_Array_SIP9 | RN1, RN2 |
Main Board design files
The KiCad project lives in the juniperlynx/Uno-14500 repository on GitHub; these links point at the commit this page was built from.
Main Board: common questions
How big is the Main Board?
The Main Board measures 212 × 126 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Main Board?
75 components, from 41 distinct parts. The full bill of materials is listed on this page.
Where can I download the Main Board design files?
From the juniperlynx/Uno-14500 repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the Main Board design in my own project?
The repository has no license, so all rights stay with juniperlynx. Use it as a reference, and ask the author before reusing the design.
