2 layers198.1 × 139.7 mm
2 layers142 × 100 mm
ZX21
fordp2002/ZX21940 Years after the Sinclair ZX81 was released this project aims to preserve the first 4 chip computer
- Size
- 142 × 100 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 133
- Nets
- 195
- Pads
- 711
- Tracks, vias
- 3,499, 214
- Pours
- 3
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 21 Nov 2020
- Updated
- 24 Dec 2020
Overview
ZX21 is an open-source printed circuit board by fordp2002, from the fordp2002/ZX21 repository on GitHub, published under the BSD-3-Clause licence. It is a 2-layer board of 142 × 100 mm with 133 parts on 195 nets, routed with 3,499 tracks and 214 vias.
It is built around the ESP32-WROOM-32, 74HCT00D and BC548, with the PN2222A, EG4208A and L7805 among its other parts. Its parts include 46 resistors, 21 capacitors, 15 connectors, 13 ICs and 10 diodes. It belongs with the retro computing and games boards and the ESP32 and FPGA and CPLD boards of this library.
Main components
6
ESP32-WROOM-32
SMD,18x25.5mm-40℃~+85℃ -98dBm 2.4GHz 2.7V~3.6V 20dBm Bluetooth4.2 ESP32-DOWDQ6 UART、SDIO、SPI、I2C、GPIO、PWM、ADC、DAC SMD,25.5x18mm WiFi Modules ROHSEspressif SystemsWiFi Modules
74HCT00D
SO-14-40℃~+125℃ 100mV、400mV 12ns@4.5V,50pF 2 2V 3.7V、4.4V 4 4.5V~5.5V 40uA 4mA 4mA 74HCT Series 800mV NAND Gate Overvoltage-tolerant input TTL Compatible CMOS SO-14 Logic Gates ROHSNexperiaLogic Gates
BC548
TO-92TO-92 Bipolar (BJT) ROHSDDFBipolar (BJT)PN2222A
TO-92-3-55℃~+150℃ 1 NPN 1A 300MHz 300mV 40V 625mW NPN TO-92-3 Bipolar (BJT) ROHSNTE ElectronicsBipolar (BJT)EG4208A
插件-20℃~+70℃ 30V 4PDT Rectangular Columnar Through Hole Plugin Slide Switches ROHSE-SwitchSlide Switches
L7805
TO-220ST0℃~+125℃@(Tj) 1 1.2A 20V 2V@(1A) 42uV 500uA 5V 73dB@(120Hz) Fixed Positive Short Circuit Protection TO-220ST Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSOSENVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
README
README.mdZX21
40 Years after the Sinclair ZX81 was released this project aims to preserve the first 4 chip computer
This a computer presevation project for the Sinclair ZX81.
Features (Hopefully).
- Drop in replacement for a ZX81
- Built in 16K+ RAM, no need for a RAM Pack
- Built in Composite Video Output
- Barrel Jack power input, center Positive
- OPTION: Single Joystick port (not compatible with quickfire etc.)
- OPTION: Switchable to 1K RAM
- OPTION: Back Porch Support for early ULAs
- OPTION: Built in support for ZX-Wespi
- OPTION: ZON-X Compatible Yamaha YM2149F Based Sound
- OPTION: Switchable between Sinclair ROM OR AT28C256 EEPROM
- OPTION: 16 Pin Box Header for DK'Tronics Keyboard
Parts
133| Qty | Value | Footprint | References |
|---|---|---|---|
| 15 | 1K | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R16, R17, R18, R19, R20, R21, R22, R23, R24, R25, R26, R27, R201, R301, R504 |
| 10 | 1N4148 | zxbus:D_DO-35_SOD27_P7.62mm_Horizontal | D1, D2, D3, D4, D5, D6, D7, D8, D101, D102 |
| 8 | 470R | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R7, R8, R9, R10, R11, R12, R13, R14 |
| 5 | 2N3904 | TO_SOT_Packages_THT:TO-92_Molded_Narrow | TR401, TR402, TR403, TR404, TR405 |
| 5 | 4K7 | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R33, R302, R501, R502, R503 |
| 4 | 10K | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R1, R101, R102, R401 |
| 4 | Conn_01x03 | zxbus:Pin_Header_Straight_1x03_Pitch2.54mm | J101, J203, J204, J302 |
| 3 | 100N | Capacitors_ThroughHole:C_Disc_D4.7mm_W2.5mm_P5.00mm | C4, C9, C501 |
| 3 | 10N | Capacitors_ThroughHole:C_Disc_D4.7mm_W2.5mm_P5.00mm | C8, C10, C102 |
| 3 | Conn_01x08 | zxbus:Pin_Header_Straight_1x08_Pitch2.54mm | J502, J503, J504 |
| 2 | 10K | Resistors_SMD:R_0603_HandSoldering | R105, R106 |
| 2 | 22U | Capacitors_ThroughHole:CP_Radial_D5.0mm_P2.50mm | C101, C302 |
| 2 | 47P | Capacitors_ThroughHole:C_Disc_D4.7mm_W2.5mm_P5.00mm | C7, C12 |
| 2 | 680R | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R2, R28 |
| 2 | Audio-Jack-3 | zxbus:ASJ_125_3_3.5mm_Jack | EAR1, MIC1 |
| 2 | BC548 | TO_SOT_Packages_THT:TO-92_Molded_Narrow | TR1, TR2 |
| 2 | Conn_01x09 | Pin_Headers:Pin_Header_Straight_1x09_Pitch2.54mm | J702, J703 |
| 2 | PN2222 | TO_SOT_Packages_THT:TO-92_Molded_Narrow | TR101, TR102 |
| 1 | 100N | Capacitors_SMD:C_0603_HandSoldering | C105 |
| 1 | 100N | Capacitors_THT:C_Disc_D5.0mm_W2.5mm_P2.50mm | C2 |
| 1 | 100P | Capacitors_ThroughHole:C_Disc_D4.7mm_W2.5mm_P5.00mm | C6 |
| 1 | 100R | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R303 |
| 1 | 10K | Resistors_THT:R_Array_SIP9 | RP1 |
| 1 | 10K | Resistors_THT:R_Array_SIP6 | RP3 |
| 1 | 10N | Capacitors_SMD:C_0603_HandSoldering | C303 |
| 1 | 10R | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R30 |
| 1 | 18K | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R4 |
| 1 | 1M | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R29 |
| 1 | 1U | Capacitors_ThroughHole:CP_Radial_D5.0mm_P2.50mm | C5 |
| 1 | 220K | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R15 |
| 1 | 220R | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R34 |
| 1 | 22uF | Capacitors_ThroughHole:CP_Axial_L11.0mm_D5.0mm_P18.00mm_Horizontal | C3 |
| 1 | 2K2 | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R6 |
| 1 | 3.5MHz | Crystals:Resonator-3pin_w7.0mm_h2.5mm | X1 |
| 1 | 330R | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R5 |
| 1 | 3V3 PSU | TO_SOT_Packages_THT:TO-220-3_Vertical | IC301 |
| 1 | 47N | Capacitors_ThroughHole:C_Disc_D4.7mm_W2.5mm_P5.00mm | C11 |
| 1 | 47P | Capacitors_THT:C_Disc_D3.0mm_W2.0mm_P2.50mm | C1 |
| 1 | 47U 25V | Capacitors_ThroughHole:CP_Radial_D5.0mm_P2.50mm | C301 |
| 1 | 555 | Housings_DIP:DIP-8_W7.62mm_Socket_LongPads | IC101 |
| 1 | 56R | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R104 |
| 1 | 62256 | zxbus:DIP-28_W15.24mm_Socket_LongPads | IC4 |
| 1 | 68R | Resistors_ThroughHole:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R103 |
| 1 | 74HCT00 | Housings_SOIC:SOIC-14_3.9x8.7mm_Pitch1.27mm | IC102 |
| 1 | 820P | Capacitors_ThroughHole:C_Disc_D4.7mm_W2.5mm_P5.00mm | C103 |
| 1 | 82P | Capacitors_ThroughHole:C_Disc_D4.7mm_W2.5mm_P5.00mm | C104 |
| 1 | AS6C4008Extra | zxbus:DIP-4_W15.24mm_Socket_LongPads | IC801 |
| 1 | AT28C256 | zxbus:DIP-28_W15.24mm_Socket_LongPads | IC2 |
| 1 | AZ1117-3.3 | TO_SOT_Packages_SMD:SOT-23_Handsoldering | IC303 |
| 1 | CVBS | zxbus:YELLOW_RCA | VIDEO1 |
| 1 | Conn_01x04 | Pin_Headers:Pin_Header_Straight_1x04_Pitch2.54mm | J301 |
| 1 | Conn_01x05 | Pin_Headers:Pin_Header_Straight_1x05_Pitch2.54mm | KB1 |
| 1 | Conn_01x06 | Pin_Headers:Pin_Header_Straight_1x06_Pitch2.54mm | J501 |
| 1 | Conn_01x08 | Pin_Headers:Pin_Header_Straight_1x08_Pitch2.54mm | KB2 |
| 1 | Conn_02x08_Odd_Even | Connectors:IDC_Header_Straight_16pins | J601 |
| 1 | Conn_02x23_Row_Letter_First | zxbus:Pin_Header_Straight_2x23_Pitch2.54mm | J701 |
| 1 | DB9_Male | Connectors:DB9MC | J401 |
| 1 | EG4208A | SamacSys_Parts:EG4208 | S1 |
| 1 | ESP32-WROOM | ESP32-footprints-Lib:ESP32-WROOM | IC302 |
| 1 | GAL16V8 | Housings_DIP:DIP-20_W7.62mm_Socket_LongPads | IC502 |
| 1 | Jack-DC | Connect:BARREL_JACK | J1 |
| 1 | L7805 | TO_SOT_Packages_THT:TO-220-3_Horizontal | REG1 |
| 1 | ULA 2C210E | zxbus:DIP-40_W15.24mm_Socket_LongPads | IC1 |
| 1 | YM2149 | zxbus:DIP-40_W15.24mm_Socket_LongPads | IC501 |
| 1 | YMZ284 | Housings_DIP:DIP-16_W7.62mm_Socket_LongPads | IC503 |
| 1 | Z80A | zxbus:DIP-40_W15.24mm_Socket_LongPads | IC3 |
| 1 | ZX81BUS | zxbus:ZX_Bus_Edge_Connector | EDGE1 |
The 125 most common of 133 parts.
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Questions
How big is the ZX21 PCB?
It measures 142 × 100 mm and has 2 copper layers, 1.6 mm thick.
What parts does the ZX21 use?
133 parts, built around the ESP32-WROOM-32, 74HCT00D, BC548 and PN2222A. 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 ZX21 KiCad files?
From the fordp2002/ZX21 repository on GitHub, at the commit this page was made from: the board is KiCad/ZX21/ZX21.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the ZX21 design in my own project?
Its repository publishes it under the BSD-3-Clause licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).