MK2 - Hardware - Other PCBs

Parallel port breakout PCB

A pass-through/breakout patch board to allow flexible (re)mapping of parallel port signals


- Parallel port DB25M (Signals from MACH3)

- - all pulled low via 10k r arrays

- System 5V/Gnd

- X limit microswitch

- Y limit microswitch

- EStop switch

Note on both Limit X/Y & Estop connections:

- switches wired as NC this time as with NO was not picking up when I'd disconnected these and not reconnected after maintenance

- series resistors in event of short to ground?

- switches pull high (normal NC state)


- Parallel port DB25F (to generic Stepper driver PCB)

- 2 x RJ12 sockets for interfacing with PIC18F4620 Interface PCB


Jumper added underneath to take 5V off RJ12a pin 6

Issues / next revision:

Although PPort on the input side has all inputs tied low, any unused pins on the output side (PPort & RJ jacks) do not.  If these are not connected to an input pin they are left floating.  So it is up to the PCB connected to these outputs to pull these if required

- Next revision, add weak pulldowns to the RJ jack data pins


Single sided home made PCB, (laser printer method)

- when I can source some cost effective vertical DB25's will revise & get a PCB made

Parallel port breakout sch A01.jpg  Parallel port breakout pcb A01.jpg


Automated feeder array PCB's

An array of 74HC238's to basically do 5 to 32 demultiplexing (active high)

Intended to connect to Siemens SiPlace 141-091 feeders

- 74HC family  so can drive with 3.3V signals if desired. 25mA output drive so can power indicator LED's as well


J-LByte (RJ12 socket, 4 data lines)

J-HByte (RJ12 socket, 4 data lines)

- All inputs pulled low

Expects a controlling byte on the above 2 jacks:

Bits 0-6 select output channel:

- This board activates on input 0-31, can extend with 3 other almost identical PCB's later if needed to a total of 128 channels

Bit 7 must be high to enable the selected output channel. This is so that on power up we can be sure output channel 0 is not active.


SiPlace 141-091 are dual feeders with shared electronics across both channels.

16 x RJ11 4 pin jacks 1 per feeder:

- Pin 1 = 1st data signal from controller 0-5v, intended for left side feeder

- Pin 2 = 2nd data signal from controller 0-5v, intended for right side feeder

- Pin 3 = Gnd

- pin 4 = +30V DC feeder supply


not in sch or pcb but  but on physical board are:

- Decoupling & reservoir caps

- 30V supply has a rectifier diode in series in event of incorrect polarity


Jumper added to take 5V off J-LByte pin 6


Single sided home made PCB, (laser printer method)

Feeder Breakout A02 20120125 1512 SCH.JPG    Feeder Breakout A02 20120125 1512 PCB.JPG


LED, Buzzer & SSR switching output for Vacuum Pump


J-In (RJ12, 3 data lines)

- Bit 0: LED indicator x 2

- Bit 1: Onboard buzzer

- Bit 2: SSR switching passthrough


SSR 0-5V output


Single sided home made PCB, (laser printer method)

Led Buzzer SSR SCH A01.jpg   Led Buzzer SSR PCB A01.jpg

4 x (optoisolated) Mosfet drivers

- as per MK1 version