LB Backplane Computer

Features

• Classic Computers design
  • Intended for multiple CPU support
  • Not RC2014 compatible (hardware)
• 24-bit address support
  • Want to build a 68008 CPU card
• 8-bit data
• 6-slot Backplane
• CPUs
  • MC6809
  • MC6802
  • 6502
  • Z80
• Memory cards
  • 16KB EPROM, 32KB RAM card
  • 16/32/64/128/256/512KB/1MB EPROM, 32/128/512KB RAM card
  • 16/32/64/128/256/512KB/1MB EPROM in ZIF socket
• I/O cards
  • ACIA
  • Smart I/O
• Prototyping cards
  • Breakout board V1
  • Breakout board V2
• Hackaday page

LB-BKPLANE-01 - Backplane

• LB-BKPLANE-01
• 6 slot backplane
• 64 connections
  • 2 power, 2 ground pins
  • 10 expansion pins
  • 0.6" slot spacine
• Optional "light" terminators
• Power connections via 2x8 header
• 100x100mm card
• (6) 4-40 mounting holes

Backplane Pinout

Pin	LBMEM	LBZ80	LB65C816	LBLOGIC
1	VCC	VCC	VCC	VCC
2	VCC	VCC	VCC	VCC
3	CPUA22	CPUA22	CPUA22	P2[6]
4	CPUA23	CPUA23	CPUA23	P2[7]
5	CPUA20	CPUA20	CPUA20	P2[4]
6	CPUA21	CPUA21	CPUA21	P2[5]
7	CPUA18	CPUA18	CPUA18	P2[2]
8	CPUA19	CPUA19	CPUA19	P2[3]
9	CPUA16	CPUA16	CPUA16	P2[0]
10	CPUA17	CPUA17	CPUA17	P2[1]
11	CPUA14	CPUA14	CPUA14	P4[6]
12	CPUA15	CPUA15	CPUA15	P4[7]
13	CPUA12	CPUA12	CPUA12	P4[4]
14	CPUA13	CPUA13	CPUA13	P4[5]
15	CPUA10	CPUA10	CPUA10	P4[2]
16	CPUA11	CPUA11	CPUA11	P4[3]
17	CPUA08	CPUA8	CPUA8	P4[0]
18	CPUA09	CPUA9	CPUA9	P4[1]
19	CPUA06	CPUA6	CPUA6	P0[6]
20	CPUA07	CPUA7	CPUA7	P0[7]
21	CPUA04	CPUA4	CPUA4	P0[4]
22	CPUA05	CPUA5	CPUA5	P0[5]
23	CPUA02	CPUA2	CPUA2	P0[2]
24	CPUA03	CPUA3	CPUA3	P0[3]
25	CPUA00	CPUA0	CPUA0	P0[0]
26	CPUA01	CPUA1	CPUA1	P0[1]
27	CPUD0	CPUD0	CPUD0	P12[0]
28	CPUD7	CPUD7	CPUD7	P12[7]
29	CPUD1	CPUD1	CPUD1	P12[1]
30	CPUD6	CPUD6	CPUD6	P12[6]
31	CPUD2	CPUD2	CPUD2	P12[2]
32	CPUD5	CPUD5	CPUD5	P12[5]
33	CPUD3	CPUD3	CPUD3	P12[3]
34	CPUD4	CPUD4	CPUD4	P12[4]
35	MEMRD*	N/A	N/A	P3[7]
36	RAMSEL*	N/A	N/A	P3[6]
37	IOCS*	N/A	N/A	P3[4]
38	ROMSEL*	N/A	N/A	P3[5]
39	GND	GND	GND	GND
40	GND	GND	GND	GND
41	N/A	CPUCLK	CPUCLK	P3[3]
42	N/A	RFSH	VPA	P3[2]
43	N/A	INT*	IRQB*	P3[1]
44	N/A	M1*	VPB	P3[0]
45	N/A	NMI*	NMIB*	P5[7]
46	N/A	CPURST*	CPURESB*	P5[6]
47	N/A	HALT*	ABORT*	P5[5]
48	N/A	BUSRQ*	MLB	P5[4]
49	N/A	MREQ*	VDA	P1[7]
50	N/A	WAIT*	RDY	P1[6]
51	N/A	IORQ*	IRQB*	P1[5]
52	N/A	BUSACK*	CPUE	P1[4]
53	N/A	CPURD*	CPUMX	P5[3]
54	N/A	CPUWR*	RWB	P5[2]
55	N/A	N/A	N/A	N/A
56	N/A	N/A	N/A	N/A
57	N/A	N/A	N/A	N/A
58	N/A	N/A	N/A	N/A
59	N/A	N/A	N/A	N/A
60	N/A	N/A	N/A	N/A
61	N/A	N/A	N/A	N/A
62	N/A	N/A	N/A	N/A
63	N/A	N/A	N/A	N/A
64	N/A	N/A	N/A	N/A

LB-65CXX-01

• LB-65CXX-01
• 65C02 or 65C816 CPU
• Oscillator on card
• Reset switch/power monitor
• Address decoder PLD drives RAM/ROM/IO chip selects
• 100x50mm card

LB-6802-01

• LB-6802-01
• 68N02 CPU
• Reset switch/power monitor
• Address decoder PLD drives RAM/ROM/IO chip selects
• 100x50mm card

LB-6809-01

• LB-6809-01
• 68B09 CPU
• Reset switch/power monitor
• Address decoder PLD drives RAM/ROM/IO chip selects
• 100x50mm card

LB-Z80-01

• LB-Z80-01
• Z80 CPU
• Oscillator on card
• Reset switch/power monitor
• Address decoder PLD drives RAM/ROM/IO chip selects
• 100x50mm card

LB-68B50-01

• LB-68B50-01
• 68B50 UART
• Baud Rate Clock (38.4k baud oscillator)
• XIAO RP2040 CPU
  • USB/Serial
• 8-bit parallel port expander
  • SD card
• 100x50mm card

LB-68B50-02

• LB-68B50-02
• 68B50 UART
• Baud Rate Clock (38.4k baud oscillator)
• Control lines from PLD allow multiple Serial I/O cards
• 100x50mm card

LB-LOGIC-01

• LB-LOGIC-01
• Not required for BASIC computer
• PSoC 5LP CPU
• USB/Serial
• 8 I/O pins
• 3.3V/5V operation
• Connects to all backplane pins
• Reset Switch
• 100x50mm

LB-MEM-02

• LB-MEM-02
• 32KB SRAM
  • Supports smaller (28-pin) SRAMs
  • Headers to jump for smaller cards
• EPROM (up to 64 KB)
• Connects to Address/Data and Memory control lines
• 50x75mm card

LB-MEM-03

• LB-MEM-03
• EPROM/EEPROM card
• 32-pin ZIF socket
• Up to 1MB
• Supports smaller SRAMs
  • Headers to jump for smaller parts
• Connects to Address/Data and Memory control lines
• 50x75mm card

LB-MEM-04

• LB-MEM-04
• 32/128KB/512KB SRAM
  • Supports 32 and 28 pin SRAMs
  • Headers to jump for smaller cards
• EPROM (up to 64 KB)
• Connects to Address/Data and Memory control lines
• 50x75mm card

LB-BKOUT-01 - Breakout Board

• LB-BKOUT-01
• Breakout all bus lines
• PWR/GND bus down the middle
• Can be used as NOP tester
• 84 x 28mm

LB-BKOUT-02 - Breadboard/Breakout Board

• LB-BKOUT-02
• Breakout all bus lines around breadboard area
• PWR/GND bus down the middle
• 3.3 x 1.7 in

LB-BKOUT-02 - Configured for Logic Analyzer

Mini360 Adapter Board

• Mini360_Adapter_Board
• Adjustable output voltage level
  • Adjust for 5V output voltage nominal
    • 5.1V is a good starting point
  • Adjust before installing onto backplane
  • Pot is not easy to adjust
• Wide range of input voltage up to 23V
  • About 1-2V higher (minimum) than output voltage
  • I used 9V, 1A wall wart
  • Works well with 9 or 12V DC wall warts
• 2x10 header for power distribution
  • Male pins plug into 2x8 female pins on LB-BKPLANE-01 card
  • Other pins can be used for attaching scope ground or other peripheral cards
• (2) 4-40 mounting holes

Typical Parts

Mouser #	Mfr. #	Manufacturer	Customer #	Description	Price (USD)
774-MXO45-2C-1M0000	MXO45-2C-1M0000	CTS	OSC_1.0MHz	Standard Clock Oscillators 1.000000 MHZ Hybrid Circuit	$1.61
774-MXO45-3C-1.8	MXO45-3C-1M8432	CTS	OSC_1.8MHz	Standard Clock Oscillators 1.84320 MHz	$3.25
774-MXO45-3C-2.0	MXO45-3C-2M0000	CTS	OSC_2.0MHz	Standard Clock Oscillators 2.00000 MHz	$2.27
556-AF16V8B15PU	ATF16V8B-15PU	Microchip	PLD	EEPLD - Electronically Erasable Programmable Logic Devices 15 ns 20 I/O Pins 8 macrocells 8 reg	$1.22
700-DS1813-5T&R	DS1813-5+T&R	Analog Devices Inc.	PWR_MON	Supervisory Circuits 5V EconoReset with Pushbutton	$3.70
535-1107741	1107741	Aries Electronics	SKT_04_DIP	IC & Component Sockets OSCILLATOR FULL 4PIN	$0.991
575-199320	110-99-320-41-001000	Mill-Max	SKT_20_DIP	IC & Component Sockets 20P TIN PIN TIN CONT	$1.17
575-11044628	110-44-628-41-001000	Mill-Max	SKT_28_DIP	IC & Component Sockets 28P TIN PIN TIN CONT	$1.63
575-1144632	110-44-632-41-001000	Mill-Max	SKT_32_DIP	IC & Component Sockets 32P TIN PIN TIN CONT	$2.27
575-11044640	110-44-640-41-001000	Mill-Max	SKT_40_DIP	IC & Component Sockets 40P TIN PIN TIN CONT	$2.61
517-4848-6000-CP	4848-6000-CP	3M	SKT_48_DIP	IC & Component Sockets 48P DUAL WIPE DIPSKT	$1.23
652-4610X-1LF-10K	4610X-101-103LF	Bourns		Resistor Networks & Arrays 10pins 10Kohms Bussed	$0.214

• 2X40 Headers
• MCP100-485DI/TO is a much less expensive part than the DS1813-T (I have not tested it) and it only monitor voltage (can't install reset switch)