HardLabs

LFlex21

laurent-fr·LFlex21·kicad/mc6809.kicad_pcb

LFlex21 PCB layout, top view — open source NXP board by laurent-fr

About the LFlex21 PCB

LFlex21 is an open source NXP PCB design by laurent-fr, published on GitHub. It is a 2-layer board measuring 180.3 × 120.7 mm, with 77 components from 48 distinct parts.

Its main chip is the MK48T12, from the NXP family. Other key parts include the TL7705A, MC6809, GAL22V10, 74LS138 and MC6840_PTM. By type, the board carries 28 capacitors, 17 ICs, 14 resistors, 8 connectors, 5 test points and 2 transistors.

From the project

6809 CPU 58Kb RAM 4Kb ROM 2Kb NVRAM RTC clock Serial interface up to 9600 bauds Centronic printer port floppy controller * FLEX09 operating system

Main components on the LFlex21

TL7705AMC6809GAL22V1074LS138MC6840_PTMMC6850_ACIAMAX20227C64628128_DIP32_SSOP32MK48T12682174HC0474LS24574LS06WD177074LS08

LFlex21 bill of materials (BOM)

77 components, 48 distinct parts.

QtyPartRefs
1
TL7705A
U1
1
MC6809
U2
1
GAL22V10
U3
1
74LS138
U4
1
MC6840_PTM
U5
1
MC6850_ACIA
U6
1
MAX202
U7
1
27C64
U8
1
628128_DIP32_SSOP32
U9
1
MK48T12
U10
1
6821
U11
1
74HC04
U13
1
74LS245
U14
2
74LS06
U15, U18
1
WD1770
U17
1
74LS08
U19
1
3.6864Mhz
Q1
1
8Mhz
Q2
1
Conn_01x02_Male
J1
1
Conn_02x17_Odd_Even
J4
Show 28 more
QtyPartRefs
1
DIN41612-a+c
J5
2
Conn_01x03_Male
J6, J9
1
Conn_01x02_Male
J7
1
Conn_01x02_Male
J8
1
Conn_01x06_Male
J10
1
SW_Push
SW1
1
SW_DIP_x04
SW2
1
E
TP1
1
GND
TP2
1
Acia_Clk
TP3
1
Floppy_8mhz
TP4
1
+5V
TP5
1
LED
D1
1
220n
C1
16
100n
C2, C6, C7, C8, C9, C10, C12, C17 +8
3
22p
C3, C4, C23
1
47u/16V
C5
5
1u
C11, C13, C14, C15, C16
1
27p
C22
1
5-15pF
C29
1
10k
R1
1
4k7
R2
2
1k
R9, R11
1
4.7M
R10
3
1K
R12, R17, R18
4
47
R13, R14, R15, R16
1
220
R19
1
4k7
RN1

LFlex21 design files

The KiCad project lives in the laurent-fr/LFlex21 repository on GitHub; these links point at the commit this page was built from.

LFlex21: common questions

What microcontroller does the LFlex21 use?

The LFlex21 is built around the MK48T12, from the NXP family.

How big is the LFlex21 PCB?

The LFlex21 measures 180.3 × 120.7 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the LFlex21?

77 components, from 48 distinct parts. The full bill of materials is listed on this page.

Where can I download the LFlex21 design files?

From the laurent-fr/LFlex21 repository on GitHub, which has the KiCad layout; the links under Design files point to each one.

Can I use the LFlex21 design in my own project?

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

Can I test firmware for the LFlex21 without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug NXP firmware against it before you order a PCB.

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