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Zx50 Cpu RevB1

mmosko·Zx50·boards/Zx50_Cpu_RevB1/Zx50_Cpu_RevB1.kicad_pcb

Zx50 Cpu RevB1 PCB layout, top view — open source board by mmosko

About the Zx50 Cpu RevB1 PCB

Zx50 Cpu RevB1 is an open source PCB design by mmosko, published on GitHub. It is a 4-layer board measuring 133.5 × 100.3 mm, with 38 components from 24 distinct parts.

Other key parts include the 74AHC1G14, SN74ABT245BN, Z84C00XXP, MCP1316MT-46LE/OT and 74LVC1G3208. By type, the board carries 12 capacitors, 10 ICs, 6 connectors, 5 resistors, 2 transistors and 2 diodes.

From the project

This is the primary CPU board for the Zx50 8-slot passive backplane system. It hosts the Z80 microprocessor (running at 8 to 10 MHz) and acts as the master controller for the primary bus.

This is the primary CPU board for the Zx50 8-slot passive backplane system. It hosts the Z80 microprocessor (running at 8 to 10 MHz) and acts as the master controller for the primary bus.

Crucially, this board is designed to coexist with the Zx50 Shadow Bus architecture. It features a hardware-level " firewall" that allows a coprocessor (like a Pi Pico on the Bus Probe or Front Panel card) to request the bus via ~BUSRQ. When the Z80 yields (~BUSAK), the CPU card instantly severs itself from the backplane, allowing the Pico to perform high-speed 40MHz DMA transfers without electrical…

Main components on the Zx50 Cpu RevB1

74AHC1G14SN74ABT245BNZ84C00XXPMCP1316MT-46LE/OT74LVC1G3208SN74AHCT74DRG474ACHT132

Zx50 Cpu RevB1 bill of materials (BOM)

38 components, 24 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
74AHC1G14
U1
4
SN74ABT245BN
U2, U3, U5, U7
1
Z84C00XXP
Z84C00xxP
U4
1
MCP1316MT-46LE/OT
U6
1
74LVC1G3208
U8
1
SN74AHCT74DRG4
U9
1
74ACHT132
U10
1
BSS84
Q1
1
2N7002-7-F
Diodes Incorporated
Q2
1
ZX50_EDGECONNECTOR
Zx50_EdgeConnector
J1
1
FrontPanelConnect
J2
1
Clock Mezzanine
J3
1
Front Panel
J4
1
TP_D_DIR
J5
1
TP_BUSAK
J6
1
RESET
SW1
1
PWR
D1
1
HALT
D2
11
0.1UF
0.1uF
C1, C2, C3, C4, C5, C6, C7, C8 +3
1
100UF
100uF
C9
Show 4 more
QtyPartRefs
2
470
R1, R4
1
10K
R2
1
47K
R3
1
33R
R8

Zx50 Cpu RevB1 design files

The KiCad project lives in the mmosko/Zx50 repository on GitHub; these links point at the commit this page was built from.

Zx50 Cpu RevB1: common questions

How big is the Zx50 Cpu RevB1 PCB?

The Zx50 Cpu RevB1 measures 133.5 × 100.3 mm, has 4 copper layers and is 1.6 mm thick.

How many components are on the Zx50 Cpu RevB1?

38 components, from 24 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.

Where can I download the Zx50 Cpu RevB1 design files?

From the mmosko/Zx50 repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.

Can I use the Zx50 Cpu RevB1 design in my own project?

The repository has no license, so all rights stay with mmosko. Use it as a reference, and ask the author before reusing the design.

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