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Free Tx/Rx pins on RAMPS?

Posted by Kyle R 
Free Tx/Rx pins on RAMPS?
August 10, 2014 03:15AM
Hi all,

Are there any free Tx/Rx pins on the RAMPS board? I want to interface with an RS232 connected device while printing.

Re: Free Tx/Rx pins on RAMPS?
August 10, 2014 03:52AM
Did this some time back... think its correct, but you should check it..

There are 4 serial ports on a mega2560, on the ramps they are mapped to the following.

2 RXD0 PE0 ( RXD0/PCINT8 ) Digital pin 0 (RX0) usb
3 TXD0 PE1 ( TXD0 ) Digital pin 1 (TX0) usb
45 RXD1 PD2 ( RXDI/INT2 ) Digital pin 19 (RX1) Z-MAX
46 TXD1 PD3 ( TXD1/INT3 ) Digital pin 18 (TX1) Z-MIN
12 RXD2 PH0 ( RXD2 ) Digital pin 17 (RX2) on aux4
13 TXD2 PH1 ( TXD2 ) Digital pin 16 (TX2) on aux4
63 RXD3 PJ0 ( RXD3/PCINT9 ) Digital pin 15 (RX3) Y-MAX
64 TXD3 PJ1 ( TXD3/PCINT10 ) Digital pin 14 (TX3) Y-MIN

Yes there is one available one aux4
And if that’s in use and your not using your max endstops you can move the endstops around a little and get a another serial working. Or move Z and Y endstops elsewhere to get another serial (I was planning to move them onto the the 4 servo lines, just note that the gnd and +5 pins have been reversed from the endstop)

So you could get 3 serial lines working for your own things.. Software.. thats another issue tongue sticking out smiley

nb these are 5v level serial pins, you will need some sort of converter to plug in real 12v serial.

Edited 3 time(s). Last edit at 08/10/2014 04:02AM by Dust.
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