MKS GEN 1.4 Free Pins?

Hello all,

I'm new to this forum.
I'm at wits end after searching over the interweb only to come back empty-handed.

I have a MKS GEN 1.4 board sporting a MKS TFT 3.2 (aux 1), a 12864 LCD (EXP1/EXP2), RGB LED string (D4/D5/D6), bltouch (D11), two extruders (D7/D10), part cooling fan (D9), dual thermistors of course. I am needing to find another output I can use PWM preferably to control the 2nd part cooling fan.

I've tried all of the pins on AUX2(D63/D64/D65/D66/D40/D42/D44) ,AUX3(D49/D50/D51/D52/D53), XMAD2) using gcode: M42 P S<0-255>
to no avail.
I see pin D12 is available on MKS GEN 1.5, but I don't see it broken out anywhere on this board.

Can anyone help me find an unused pin on the MKS GEN 1.4 board please?

on the 2560 only certain pins have PWM capability

Pin Number Pin Name Mapped (arduino) Pin Name
1 PG5 ( OC0B ) Digital pin 4 (PWM) USED
5 PE3 ( OC3A/AIN1 ) Digital pin 5 (PWM) USED
6 PE4 ( OC3B/INT4 ) Digital pin 2 (PWM) X+
7 PE5 ( OC3C/INT5 ) Digital pin 3 (PWM) X-
15 PH3 ( OC4A ) Digital pin 6 (PWM) USED
16 PH4 ( OC4B ) Digital pin 7 (PWM) USED
17 PH5 ( OC4C ) Digital pin 8 (PWM) USED??
18 PH6 ( OC2B ) Digital pin 9 (PWM) USED
23 PB4 ( OC2A/PCINT4 ) Digital pin 10 (PWM) USED
24 PB5 ( OC1A/PCINT5 ) Digital pin 11 (PWM) USED
25 PB6 ( OC1B/PCINT6 ) Digital pin 12 (PWM)
26 PB7 ( OC0A/OC1C/PCINT7 ) Digital pin 13 (PWM) LED (probably)
38 PL3 ( OC5A ) Digital pin 46 (PWM) Z_STEP_PIN
39 PL4 ( OC5B ) Digital pin 45 (PWM)
40 PL5 ( OC5C ) Digital pin 44 (PWM) aux-2

I presume D8 is still the bed....

leaving D12,D44,D45, to find

EDIT: D44 on AUX-2 should have worked....
I suspect it doesn't becase its #define E1_CS_PIN 44 so probably removed from M42 control.
This is not used unless you have SPI based stepper drivers.

Or you could use which X endstop you not using currently... as they are both PWM outs

Edited 5 time(s). Last edit at 02/13/2018 10:38PM by Dust.