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ceteras·CoBra·mainboard/2layer/kicad/main.kicad_pcb

Main PCB layout, top view — open source board by ceteras

About the Main PCB

Main is an open source PCB design by ceteras, published on GitHub under the MIT license. It is a 2-layer board measuring 299.2 × 180 mm, with 352 components from 69 distinct parts.

Other key parts include the MMN2716, 74LS74, 74LS153, MMN4116 and 74LS193. By type, the board carries 114 resistors, 92 ICs, 51 capacitors, 47 jumpers, 17 connectors and 11 diodes.

It belongs with the retro computing and test & measurement designs in this gallery.

From the project

A Z80 retro computer, ZX Spectrum compatible, can also run CP/M.

CoBra is a Z80 computer designed in 1986 at ITCI, a research center in Brasov, Romania.

In its official version, its specs are: - 3.5MHz Z80A CPU - 64KB ram, made up of 4 banks of 8x 4116 chips each - 2KB - 16KB ROM boot code (original firmware fits in 2K) - 16KB ROM for the BASIC interpreter (8x 2716 or 4x 2732) - 256 x 192 resolution ZX Spectrum video interface - 58 keys keyboard, featuring 50 keys for ZX Spectrum mode plus 8 for CP/M - i8272 floppy interface - on a daughter board (not included in the repo for now) - RS232 port (bit-banged) - joystick port - 8 bit parallel port, input…

Main, from the project README
From the project README

Main components on the Main

MMN271674LS7474LS153MMN411674LS19374LS1074LS0074LS0874LS5174LS2074LS8674LS15774LS1174LS0474LS4274LS95CDB407P8212825527C128Z80CPULM741

Main bill of materials (BOM)

352 components, 69 distinct parts.

QtyPartRefs
8
MMN2716
U1, U18, U23, U42, U59, U75, U84, U91
4
74LS74
U2, U15, U36, U61
4
74LS153
U3, U20, U22, U39
32
MMN4116
U4, U5, U6, U7, U8, U9, U10, U11 +24
4
74LS193
U12, U13, U32, U33
2
74LS10
U14, U40
6
74LS00
U16, U17, U37, U54, U55, U87
2
74LS08
U19, U38
1
74LS51
U21
1
74LS20
U34
2
74LS86
U35, U88
5
74LS157
U41, U51, U58, U80, U85
1
74LS11
U52
2
74LS04
U53, U57
2
74LS42
U56, U70
6
74LS95
U60, U77, U78, U81, U82, U83
5
CDB407
U71, U72, U73, U74, U86
1
P8212
U76
1
8255
U79
1
27C128
U89
Show 49 more
QtyPartRefs
1
Z80CPU
U90
1
LM741
U92
1
2N2219
Q2
1
14MHz
Y1
2
Conn_01x10
J1, J6
1
C96ABC
J2
3
DIN-5
J3, J4, J9
2
Conn_01x01_Male
J5, J8
1
Conn_02x10_Odd_Even_MountingPin
J7
8
1N4148
P11, P12, P13, P14, P15, P16, P17, P18
3
150
CAT1, CCS1, CHB1
2
390
CCC1, CVR1
5
1N4148
DBR1, DBR2, DBR3, DBR4, DBR5
2
Conn_01x10
JA5, JB5
2
Conn_01x15
JEXA1, JEXB1
5
Jumper_NC_Small
JP1, JP3, JP5, JP7, JP9
5
Jumper_NO_Small
JP2, JP4, JP6, JP8, JP10
34
SolderJumper_2_Open
JP11, JP12, JP13, JP14, JP15, JP16, JP17, JP18 +26
3
SolderJumper_3_Open
JP45, JP46, JP47
1
~
RSW1
1
BC327
T2
2
~
TP1, TP2
10
1N4148
D1, D2, D3, D4, D6, D7, D8, D9 +2
1
4V7
D5
26
100n
C1, C2, C3, C4, C7, C9, C10, C11 +18
15
100n
C5, C8, C16, C22, C31, C33, C35, C38 +7
2
150
C6, C14
2
10u
C15, C45
1
220p
C24
1
15p
C30
1
270
C36
1
220u
C42
1
1500uF
C43
1
100u
C44
22
33
R1, R2, R3, R4, R5, R7, R8, R18 +14
12
1K
R6, R20, R22, R23, R26, R27, R31, R34 +4
4
2K2
R9, R84, R87, R107
19
4k7
R10, R11, R12, R13, R14, R15, R16, R17 +11
23
680
R35, R38, R45, R46, R47, R49, R50, R51 +15
1
360
R44
2
150
R48, R92
1
330
R70
5
100
R71, R75, R76, R77, R91
7
470
R72, R78, R79, R80, R81, R82, R83
2
220
R74, R86
6
10K
R88, R89, R90, R95, R97, R98
1
75
R93
8
8K2
R99, R100, R101, R102, R103, R104, R105, R106
1
240
RN1

Main design files

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

Main: common questions

How big is the Main PCB?

The Main measures 299.2 × 180 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Main?

352 components, from 69 distinct parts. The full bill of materials is listed on this page.

Where can I download the Main design files?

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

Can I use the Main design in my own project?

Yes, under the terms of its MIT license, which ceteras chose for the repository.

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