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
- 1.61 mm
- Parts
- 25
- Nets
- 173
- Pads
- 417
- Tracks, vias
- 372, 212
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 28 May 2024
- Updated
- 26 Jul 2024
Overview
LPT 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 25 parts on 173 nets, routed with 372 tracks and 212 vias.
It is built around the 74AHC541D, 74HC138 and 74HCT574D, with the 74HC00D and 74HC02 among its other parts. Its parts include 8 capacitors, 7 ICs and 2 connectors. It belongs with the retro computing and games boards of this library.
Main components
5
74AHC541D
SO-20-300mil-40℃~+125℃ 1 2V~5.5V 74AHC 8 80uA 8mA 8mA 9ns@5.5V,50pF Schmitt trigger Tri-State Unidirectional SO-20-300mil Buffers, Drivers, Receivers, Transceivers ROHSNexperiaBuffer/Driver/Transceiver
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, Decoders74HCT574D
SO-20-300mil-40℃~+125℃ 1 18ns@4.5V,50pF 3.5pF 3ns 4.5V~5.5V 5ns 69MHz 6mA 6mA 74HCT Series 8 8uA D-Type Rising Edge Tri-State SOIC-20-300mil Flip Flops ROHSNexperiaFlip Flops
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 Gates74HC02
-- Logic Gates ROHSonsemiLogic Gates
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
25| Qty | Value | Footprint | References |
|---|---|---|---|
| 7 | 100n | Capacitor_SMD:C_0805_2012Metric | C1, C2, C3, C4, C5, C6, C7 |
| 2 | 74HC138 | Package_DIP:DIP-16_W7.62mm | U1, U2 |
| 2 | 74HCT574 | Package_DIP:DIP-20_W7.62mm | U5, U6 |
| 1 | 10k | Resistor_THT:R_Array_SIP6 | RN1 |
| 1 | 10µ | Capacitor_THT:CP_Radial_D5.0mm_P2.50mm | C8 |
| 1 | 74AHC541 | Package_DIP:DIP-20_W7.62mm | U4 |
| 1 | 74HC00 | Package_DIP:DIP-14_W7.62mm | U3 |
| 1 | 74HC02 | Package_DIP:DIP-14_W7.62mm | U7 |
| 1 | Bus_PCI_6502 | Connector_PCBEdge:BUS_PCI | J2 |
| 1 | Control | Jumper:SolderJumper-3_P2.0mm_Open_TrianglePad1.0x1.5mm_NumberLabels | JP2 |
| 1 | DB25_Receptacle | Connector_Dsub:DSUB-25_Female_EdgeMount_P2.77mm | J1 |
| 1 | Data | Jumper:SolderJumper-3_P2.0mm_Open_TrianglePad1.0x1.5mm_NumberLabels | JP1 |
| 1 | LOGO | Eigene:logo | G*** |
| 1 | Val** | Eigene:ladder_4 | Ref** |
The 22 most common of 25 parts.
Questions
How big is the LPT PCB?
It measures 83.3 × 68.2 mm and has 4 copper layers, 1.61 mm thick.
What parts does the LPT use?
25 parts, built around the 74AHC541D, 74HC138, 74HCT574D and 74HC00D. 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 LPT KiCad files?
From the Synthron/S65 repository on GitHub, at the commit this page was made from: the board is Hardware/modules/LPT/LPT.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 LPT 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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