2 layers209 × 175 mm
Excalibur64
Cptscorcher/Excallibur-64
A reimagining of the seminal Excalibur 64 Computer
126 partsGPL-3.0
2 layers160 × 120 mm
Vireo rev2
ceharris/sb6502-mk2Program support for my SB6502 Mk2 computer
- Size
- 160 × 120 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 73
- Nets
- 128
- Pads
- 503
- Tracks, vias
- 1,449, 100
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 17 Feb 2025
- Updated
- 4 Feb 2026
Overview
Vireo rev2 is an open-source printed circuit board by ceharris, from the ceharris/sb6502-mk2 repository on GitHub, published under the MIT licence. It is a 2-layer board of 160 × 120 mm with 73 parts on 128 nets, routed with 1,449 tracks and 100 vias.
It is built around the 74HC125D, MAX232N and 74HC138, with the 74HC273D among its other parts. Its parts include 25 connectors, 18 capacitors, 12 ICs, 9 resistors and 2 diodes. It belongs with the FPGA and CPLD boards of this library.
Main components
4
74HC125D
SO-14-40℃~+125℃ 1 11ns@4.5V,50pF 160uA 2V~6V 4 7.8mA 7.8mA 74HC Tri-State Unidirectional SOIC-14 Buffers, Drivers, Receivers, Transceivers ROHSNexperiaBuffers, Drivers, Receivers, Transceivers
MAX232N
PDIP-160℃~+70℃ 120Kbps 2 2 4.5V~5.5V Transceiver PDIP-16 RS232 ICs ROHSTexas InstrumentsRS232 ICs
74HC138
SOP-160℃~+70℃ 24ns@5.0V,16pF 2V~6V 3/8 5.2mA 5.2mA 5uA 74HC Decoder Reverse function Single Supply SOP-16 Signal Switches, Multiplexers, Decoders ROHSGRSignal Switches, Multiplexers, Decoders
74HC273D
SOIC-20-300mil-40℃~+125℃ 1 12ns 15ns@4.5V,50pF 2V~6V 3.5pF 30MHz 3ns 74HC Series 8 8uA D-Type Reset Rising Edge SO-20-300mil Flip Flops ROHSNexperiaFlip Flops
README
README.mdsb6502-mk2
A single board computer project using the WDC 65C02 microprocessor.
Key hardware features in this design:
- 65C02 microprocessor clocked at 1.8432 MHz
- 32K ROM and 128K RAM with flexible bank switching support
- PLD-based system logic
- Pin sockets for 6502 bus signals to allow easy connection to external devices
- On board serial console using MC68B50 ACIA operating at 115 kbps, including hardware flow control, and both TTL and RS-232 terminal connection points
- On board WDC 65C22 Versatile Interface Processor (VIA) with pin sockets for all GPIO and control signals
- Switchable interrrupt request configuration for on-board VIA and ACIA allowing either wired-OR or use of an external interrupt controller to manage the 6502's /IRQ input.
Key software features in this design:
- TailForth 2 in ROM
- Initial program load (IPL) allows system programs to be uploaded in either Motorola SREC or Intel Hex records, directly transferred to RAM and executed.
Parts
73| Qty | Value | Footprint | References |
|---|---|---|---|
| 13 | 100nF | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P2.50mm | C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17 |
| 7 | Conn_01x08_Socket | Connector_PinSocket_2.54mm:PinSocket_1x08_P2.54mm_Vertical | J4, J6, J12, J13, J14, J15, J16 |
| 5 | 3K3 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R2, R3, R4, R5, R8 |
| 5 | Conn_01x04_Socket | Connector_PinSocket_2.54mm:PinSocket_1x04_P2.54mm_Vertical | J10, J11, J17, J18, J25 |
| 4 | 1µ | Capacitor_THT:CP_Radial_D4.0mm_P2.00mm | C1, C2, C3, C4 |
| 4 | Conn_01x02_Socket | Connector_PinSocket_2.54mm:PinSocket_1x02_P2.54mm_Vertical | J5, J7, J19, J21 |
| 4 | MountingHole_Pad | MountingHole:MountingHole_3.2mm_M3_Pad | H1, H2, H3, H4 |
| 3 | 10K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R1, R6, R10 |
| 3 | Conn_01x03_Pin | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J1, J2, J24 |
| 2 | ATF22V10 | Package_DIP:DIP-24_W7.62mm_Socket | U4, U5 |
| 1 | 1.8432 MHz | Oscillator:Oscillator_DIP-8 | X1 |
| 1 | 10µF | Capacitor_THT:CP_Radial_D4.0mm_P2.00mm | C18 |
| 1 | 1K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R7 |
| 1 | 1N914 | Diode_THT:D_DO-35_SOD27_P7.62mm_Horizontal | D1 |
| 1 | 2N7000 | Package_TO_SOT_THT:TO-92_Inline | Q1 |
| 1 | 74HC125 | Package_DIP:DIP-14_W7.62mm_Socket | U12 |
| 1 | 74HC138 | Package_DIP:DIP-16_W7.62mm_Socket | U11 |
| 1 | 74HC273 | Package_DIP:DIP-20_W7.62mm_Socket | U3 |
| 1 | AT28C256 | Socket:DIP_Socket-28_W11.9_W12.7_W15.24_W17.78_W18.5_3M_228-1277-00-0602J | U7 |
| 1 | Barrel_Jack | Connector_BarrelJack:BarrelJack_CUI_PJ-063AH_Horizontal | J20 |
| 1 | Conn_01x06_Socket | Connector_PinSocket_2.54mm:PinSocket_1x06_P2.54mm_Vertical | J22 |
| 1 | Conn_01x07_Socket | Connector_PinSocket_2.54mm:PinSocket_1x07_P2.54mm_Vertical | J8 |
| 1 | Conn_01x16_Socket | Connector_PinSocket_2.54mm:PinSocket_1x16_P2.54mm_Vertical | J9 |
| 1 | Conn_02x03_Odd_Even | Connector_PinSocket_2.54mm:PinSocket_2x03_P2.54mm_Vertical | J23 |
| 1 | DE9_Receptacle | Connector_Dsub:DSUB-9_Socket_Horizontal_P2.77x2.84mm_EdgePinOffset4.94mm_Housed_MountingHolesOffset4.94mm | J3 |
| 1 | HM628128 | Package_DIP:DIP-32_W15.24mm_Socket | U6 |
| 1 | LED | LED_THT:LED_D3.0mm | D2 |
| 1 | MAX232 | Package_DIP:DIP-16_W7.62mm_Socket | U9 |
| 1 | MC68B50 | Package_DIP:DIP-24_W15.24mm_Socket | U8 |
| 1 | SW_Push | Button_Switch_THT:SW_PUSH_6mm | SW1 |
| 1 | TC1213 | Package_DIP:DIP-8_W7.62mm_Socket | U1 |
| 1 | W65C02SxP | Package_DIP:DIP-40_W15.24mm_Socket | U2 |
| 1 | W65C22NxP | Package_DIP:DIP-40_W15.24mm_Socket | U10 |
Questions
How big is the Vireo rev2 PCB?
It measures 160 × 120 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Vireo rev2 use?
73 parts, built around the 74HC125D, MAX232N, 74HC138 and 74HC273D. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Vireo rev2 KiCad files?
From the ceharris/sb6502-mk2 repository on GitHub, at the commit this page was made from: the board is hw/rev2/vireo-rev2.kicad_pcb and its schematic hw/interrupt-controller/interrupt-controller.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Vireo rev2 design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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