2 layers57.2 × 73.7 mm
Programmer
derpflanz/castle-runner
This is my hobby project in making a 6502 based 8-bit computer from scratch. The end goal is to have it run Castle Runner, a game I made many moons ago.
3 parts
2 layers178.4 × 115.6 mm
CR2021 CPU v2
derpflanz/castle-runnerThis is my hobby project in making a 6502 based 8-bit computer from scratch. The end goal is to have it run Castle Runner, a game I made many moons ago.
- Size
- 178.4 × 115.6 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 47
- Nets
- 172
- Pads
- 550
- Tracks, vias
- 1,050, 59
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 31 Jan 2021
- Updated
- 24 Aug 2026
Overview
CR2021 CPU v2 is an open-source printed circuit board by derpflanz, from the derpflanz/castle-runner repository on GitHub. It is a 2-layer board of 178.4 × 115.6 mm with 47 parts on 172 nets, routed with 1,050 tracks and 59 vias.
It is built around the ATMEGA328-PU, 74LS540PC and LM324, with the 74HCU04D, 74LS163APC and 74LS273PC among its other parts. Its parts include 8 ICs, 3 capacitors, 3 resistors, 2 connectors and 1 diode. It belongs with the AVR (ATmega, ATtiny) boards of this library.
Main components
6
ATMEGA328-PU
PDIP-28-40℃~+85℃ 1.8V~5.5V 10bit 1KB 20MHz 23 2KB 32KB 8 Bit AVR Built-in FLASH PDIP-28 Microcontrollers (MCU/MPU/SOC) ROHSMicrochip TechnologyMicrocontrollers (MCU/MPU/SOC)
74LS540PC
DIP-200℃~+70℃ 15mA 4.75V~5.25V 74LS 75mA 8 Schmitt trigger Tri-State Unidirectional DIP-20 Buffers, Drivers, Receivers, TransceiversTexas InstrumentsBuffers, Drivers, Receivers, Transceivers
LM324
SOP-14-1.5V~10V 0℃~+70℃ 24V 250nA 3V~20V 4 40mA 50nA 700uA 7mV 80dB SOP-14 Operational Amplifier ROHSHXY MOSFETOperational Amplifier74HCU04D
SO-14-40℃~+125℃ 1.7V~4.8V 1.8V、4V、5.5V 12ns@6V,50pF 200mV、260mV、500mV 2V~6V 2uA 300mV~1.2V 5.2mA 5.2mA 6 74HCU Push-pull StandardCMOS SO-14 Inverters ROHSNexperiaInverters
74LS163APC
DIP-164 74LS Programmable divide ratio、Reset function、Cascade counter、Synchronous counting DIP-16 Counters, Dividers ROHSTexas InstrumentsCounters, Dividers74LS273PC
PDIP-201 15ns 27mA 27ns@5V,15pF 30MHz 5ns 74LS Series 8 D-Type Reset Rising Edge PDIP-20 Flip Flops ROHSonsemiFlip Flops
README
README.mdcastle-runner
This is my hobby project in making a 6502 based 8-bit computer from scratch. The end goal is to have it run Castle Runner, a game I made many moons ago.
CR Assembler
Castle Runner is built from scratch, including the assembler (new version, written in C). I created my own assembly language dialect to assemble the machine language code. That ML can then be written to a EEPROM. For which I built my own EEPROM programmer.
Layout
By default, the RESET vector is set to $8000, which is the start of the ROM in the CR001 computer. The VirtualCR001 uses that as well by default. When programming the EEPROM, this vector is sent as the first two bytes and stored in $FFFC/$FFFD in the ROM.
Note that the assembler can have a DATA section at the start, which will cause to use another RESET vector to be written at the start of the .hex file.
Parts
47| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 74LS273 | Package_DIP:DIP-20_W7.62mm | $4002, $4003, OUT1, OUT2 |
| 2 | 22pF | Capacitor_THT:CP_Radial_Tantal_D4.5mm_P2.50mm | C1, C2 |
| 2 | 7400 | Package_DIP:DIP-14_W7.62mm | U3, U4 |
| 2 | 74LS138 | Package_DIP:DIP-16_W7.62mm | IN_DEMUX1, OUT_DEMUX1 |
| 2 | 74LS540 | Package_DIP:DIP-20_W7.62mm | IN1, IN2 |
| 2 | LM324 | Package_DIP:DIP-14_W7.62mm | U1, U7 |
| 1 | !IO_Active | Connector_PinHeader_2.54mm:PinHeader_1x01_P2.54mm_Vertical | PIN2 |
| 1 | +5V | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | CONN6 |
| 1 | 100uF | Capacitor_THT:CP_Radial_D6.3mm_P2.50mm | C3 |
| 1 | 10M | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R_CLK1 |
| 1 | 10k | Potentiometer_THT:Potentiometer_Piher_PT-10-V10_Vertical | RPOT1 |
| 1 | 1k | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P5.08mm_Horizontal | R1 |
| 1 | 22 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R_CLK2 |
| 1 | 3.3k | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P5.08mm_Horizontal | R3 |
| 1 | 32 kB RAM | Package_DIP:DIP-28_W15.24mm | RAM1 |
| 1 | 330 | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P5.08mm_Horizontal | R2 |
| 1 | 74HCU04 | Package_DIP:DIP-14_W7.62mm | U2 |
| 1 | 74LS163 | Package_DIP:DIP-16_W7.62mm | U5 |
| 1 | ADDRBUS_16BIT | Connector_PinHeader_2.54mm:PinHeader_1x16_P2.54mm_Vertical | BUS2 |
| 1 | ADDRSEL_IN | Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical | CONN7 |
| 1 | ADDRSEL_OUT | Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical | CONN8 |
| 1 | ATmega328-P | Package_DIP:DIP-28_W7.62mm | U6 |
| 1 | Atmega328 Programmer Interface | Connector_IDC:IDC-Header_2x03_P2.54mm_Vertical | J3 |
| 1 | Conn_02x06_Odd_Even | Connector_PinHeader_2.54mm:PinHeader_2x06_P2.54mm_Vertical | J1 |
| 1 | Crystal 8MHz | Crystal:Crystal_HC18-U_Vertical | Y1 |
| 1 | DATABUS_8BIT | Connector_PinHeader_2.54mm:PinHeader_1x08_P2.54mm_Vertical | BUS1 |
| 1 | Display | Connector_PinHeader_2.54mm:PinHeader_1x16_P2.54mm_Vertical | CONN5 |
| 1 | EXT_CLK | Connector_PinHeader_2.54mm:PinHeader_1x01_P2.54mm_Vertical | PIN_CLK1 |
| 1 | IN1 | Connector_Dsub:DSUB-9_Male_Horizontal_P2.77x2.84mm_EdgePinOffset9.90mm_Housed_MountingHolesOffset11.32mm | CONN3 |
| 1 | IN2 | Connector_Dsub:DSUB-9_Male_Horizontal_P2.77x2.84mm_EdgePinOffset9.90mm_Housed_MountingHolesOffset11.32mm | CONN4 |
| 1 | IO_Active | LED_THT:LED_D3.0mm | D1 |
| 1 | OUT1 | Connector_Dsub:DSUB-9_Male_Horizontal_P2.77x2.84mm_EdgePinOffset9.90mm_Housed_MountingHolesOffset11.32mm | CONN1 |
| 1 | OUT2 | Connector_Dsub:DSUB-9_Male_Horizontal_P2.77x2.84mm_EdgePinOffset9.90mm_Housed_MountingHolesOffset11.32mm | CONN2 |
| 1 | R/!W | Connector_PinHeader_2.54mm:PinHeader_1x01_P2.54mm_Vertical | PIN1 |
| 1 | RESET | Button_Switch_THT:SW_Tactile_Straight_KSL0Axx1LFTR | SW1 |
| 1 | ROM ZIF Socket | Package_DIP:DIP-28_W15.24mm | ROM1 |
| 1 | Speaker | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | LS1 |
| 1 | W65C22NxP | Package_DIP:DIP-40_W15.24mm | U8 |
| 1 | WD65C02S | Package_DIP:DIP-40_W15.24mm | CPU1 |
More from derpflanz/castle-runner
1Similar boards
- 4 layers96 × 70 mm
SPI Unit
oberrow/i8088-computer
Code for an i8088-based non-PC compatible breadboard computer
29 parts1MIT - 2 layers320.7 × 155.8 mm
- 2 layers426 × 307 mm
I7000
felipesanches/Itautec_I7000_KICAD
Esquemáticos do computador Itautec I-7000 G desenhados a partir de inspeção do circuito das PCBs
115 parts - 4 layers298.9 × 270 mm
Dino v0 0 2
robertrico/dino-homebrew
A perfboard with the bus edge and the slot decode every DINO card repeats. Plug it into any of J1-J8 on the Rev 1.0 mainboard, pick the slot with one shunt, bodge the card on the grid.
239 parts - 2 layers235 × 160 mm
Input output.Disk
lynchaj/duodyne
Duodyne is a hobbyist retrocomputer system designed to run ROMWBW. It is comprised of modules on a system bus
136 parts15 - 2 layers57.9 × 83.9 mm
KEY2USB
acwright/KEY2USB
Commodore 64 / C128 expansion port cartridge to USB HID keyboard
23 parts4CERN-OHL-P-2.0 - 2 layers95.1 × 72.1 mm
- 2 layers100 × 100 mm
Questions
How big is the CR2021 CPU v2 PCB?
It measures 178.4 × 115.6 mm and has 2 copper layers, 1.6 mm thick.
What parts does the CR2021 CPU v2 use?
47 parts, built around the ATMEGA328-PU, 74LS540PC, LM324 and 74HCU04D. 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 CR2021 CPU v2 KiCad files?
From the derpflanz/castle-runner repository on GitHub, at the commit this page was made from: the board is ComputerDesigns/CR2021_CPU_v2/CR2021_CPU_v2.kicad_pcb and its schematic ComputerDesigns/CR2021_CPU_v2/6522.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the CR2021 CPU v2 design in my own project?
Its repository states no licence, so its author keeps all rights: ask derpflanz before reusing the design.