2 layers83.3 × 68.2 mm
4 layers83.3 × 68.2 mm
Yet another 8bit Retro Computer
- Size
- 83.3 × 68.2 mm
- Copper layers
- 4
- Thickness
- 2.61 mm
- Parts
- 22
- Nets
- 119
- Pads
- 385
- Tracks, vias
- 561, 240
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 28 May 2024
- Updated
- 26 Jul 2024
Overview
CPU is an open-source printed circuit board by Synthron, from the Synthron/S65 repository on GitHub. It is a 4-layer board of 83.3 × 68.2 mm with 22 parts on 119 nets, routed with 561 tracks and 240 vias.
It is built around the 74HC245D, 74HC00D and 74LS573PC. Its parts include 6 connectors, 5 capacitors and 4 ICs. It belongs with the retro computing and games boards of this library.
Main components
3
74HC245D
SO-20-300mil-40℃~+125℃ 1 160uA 2V~6V 7.8mA 7.8mA 74HC 8 9ns@4.5V,50pF Bidirectional Tri-State SOIC-20-300mil Buffers, Drivers, Receivers, Transceivers ROHSNexperiaBuffers, Drivers, Receivers, Transceivers
74HC00D
SOP-14-40℃~+125℃ 1.5V、3.15V、4.2V 1.9V、3.7V、5.9V 100mV、400mV、400mV 2 2V~6V 4 40uA 5.2mA 5.2mA 500mV~1.8V 74HC Series 7ns@6V,50pF NAND Gate SOIC-14 Logic Gates ROHSNexperiaLogic Gates
74LS573PC
DIP-200℃~+70℃ 10ns 3ns 4.75V~5.25V 74LS 8 D Latch Tri-State DIP-20 Latches ROHSTexas InstrumentsLatches
README
README.mdS65xx Computer System
Yet another 8bit Retro Computer
Completely bloated, overkill and fully hackable!
ToDo
- Finish Hardware
- Software
- WozMon
- Implement Serial IO
- Implement Input Buffer
- extended for block write
- Kernel Functions
- General SysCalls
- Hardware Drivers
- RAM-Kernel
- Basic
- EhBasic
- File System
- Operating System
- WozMon
- Hardware
- order PCBs
- order parts
- solder together
Hardware
- Modules
- Backplane Bus
- CPU
- ROM
- RAM
- Bank/IRQ
- LCD/IRQ
- SIO
- PIO
- User Ports
- IDE
- Simple-IDE
- CF
- SID
- Addr + RTC + Clock
- Prototyping Board
- LPT Interface
- MyCPU Graphics Unit Interface
Software Brainstorm
- EhBasic
- maybe Microsoft Basic? See Ben Eater
- both in different banks
- maybe Microsoft Basic? See Ben Eater
- WozMon Main Boot
- Serial Program Bootloader
- File System (FAT?)
- DOS-Like UI
boot routine:
- selftest
- RAM Check
- ROM Check + version
- Load Kernel functions to RAM
- Start Monitor
Memory Map
General:
| Start | End | Usage | Size |
|---|---|---|---|
| 0000 | 7FFF | RAM | 32.768 |
| 8000 | BEFF | RAM Banked | 16.128 |
| BF00 | BFFF | IO Space | 256 |
| C000 | FFFF | ROM Banked | 16.384 |
IO Space:
| Start | End | Usage | Size |
|---|---|---|---|
| BF00 | BF07 | Bank & IRQ | 8 |
| BF08 | BF0F | TPI IDE | 8 |
| BF10 | BF12 | LPT | 2 |
| BF13 | BF14 | --- (LPT2) | 2 |
| BF14 | BF16 | MyCPU VGA | 3 |
| BF17 | BF1B | --- | 5 |
| BF1C | BF1F | PIA LEDs | 4 |
| BF20 | BF2F | VIA 1 LCD IRQ | 16 |
| BF30 | BF3F | VIA 2 | 16 |
| BF40 | BF4F | VIA 3 | 16 |
| BF50 | BF53 | ACIA 1 | 4 |
| BF54 | BF57 | ACIA 2 | 4 |
| BF58 | BF5B | --- (ACIA 3) | 4 |
| BF5C | BF5F | --- (ACIA 4) | 4 |
| BF60 | BF7F | SID 8580 | 32 |
| BF80 | BF87 | Simple IDE | 8 |
| BF88 | BF8F | CF Card | 8 |
| BF90 | BF9F | RTC | 16 |
| BFA0 | BFFF | --- | 96 |
Interrupts
The TPI Chip for the memory banks also functions as a priority interrupt controller, providing 5 seperate interrupt lines.
IRQ_0 is further divided into 8 lines for communication modules, giving an overall of 14 available IRQ-Lines.
These are currently used as follows:
- IRQ -> TPI
- IRQ_0 -> VIA0
- IRQ_0.0 -> ACIA0
- IRQ_0.1 -> ACIA1
- IRQ_0.2 -> ACIA2
- IRQ_0.3 -> ACIA3
- IRQ_0.4 -> RTC
- IRQ_0.5 -> ---
- IRQ_0.6 -> ---
- IRQ_0.7 -> ---
- IRQ_1 -> VIA1
- IRQ_2 -> VIA2
- IRQ_3 -> ---
- IRQ_4 -> ---
- IRQ_0 -> VIA0
- NMI -> ---
Note that the NMI is connected to a push button on the bus board.
Parts
22| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 100n | Capacitor_SMD:C_0805_2012Metric | C1, C2, C3, C4 |
| 1 | 10µ | Capacitor_THT:CP_Radial_D5.0mm_P2.50mm | C5 |
| 1 | 3k3 | Resistor_THT:R_Array_SIP9 | RN1 |
| 1 | 65C02 / 65816 | Package_DIP:DIP-40_W15.24mm | U1 |
| 1 | 74HC00 | Package_DIP:DIP-14_W7.62mm | U2 |
| 1 | 74HC245 | Package_DIP:DIP-20_W7.62mm_LongPads | U3 |
| 1 | 74LS573 | Package_DIP:DIP-20_W7.62mm | U4 |
| 1 | ABORT | Jumper:SolderJumper-3_P1.3mm_Open_RoundedPad1.0x1.5mm_NumberLabels | J1 |
| 1 | Bank Bridge A | Connector_PinHeader_2.54mm:PinHeader_1x08_P2.54mm_Vertical | J5 |
| 1 | Bank Bridge B | Connector_PinHeader_2.54mm:PinHeader_1x08_P2.54mm_Vertical | J6 |
| 1 | Bank Bridge C | Connector_PinHeader_2.54mm:PinHeader_1x08_P2.54mm_Vertical | J7 |
| 1 | Bus_PCI_6502 | Connector_PCBEdge:BUS_PCI | J3 |
| 1 | E | Jumper:SolderJumper-2_P1.3mm_Open_RoundedPad1.0x1.5mm | JP1 |
| 1 | LOGO | Eigene:logo | G*** |
| 1 | SO/MX | Jumper:SolderJumper-3_P1.3mm_Open_RoundedPad1.0x1.5mm_NumberLabels | J2 |
| 1 | Val** | Eigene:ladder_4 | Ref** |
The 19 most common of 22 parts.
Questions
How big is the CPU PCB?
It measures 83.3 × 68.2 mm and has 4 copper layers, 2.61 mm thick.
What parts does the CPU use?
22 parts, built around the 74HC245D, 74HC00D and 74LS573PC. 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 CPU KiCad files?
From the Synthron/S65 repository on GitHub, at the commit this page was made from: the board is Hardware/modules/CPU/CPU.kicad_pcb and its schematic Hardware/modules/ACIA2/ACIA2.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the CPU design in my own project?
Its repository states no licence, so its author keeps all rights: ask Synthron before reusing the design.
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