GPIO Control Woes

Hi Bill!

I'm trying again to get this to work with GPIO commands. So far, I can issue commands using Macros in Marlin, but when I try to send commands from a G-Code file, it frequently fails, such as producing 6 pulses instead of 7 for Reset. Also, senting the command to select feeder 0 and feed for 21.2 seconds, it will just hold the line triggers indefinately. I'm not sure where it's failing. Here is the code I'm attempting to test with:

; Initilize Port and 3D Chameleon
M42 P45 I1 T1S0 ; Initialize port and turn on
G4 P150
M42 P45 S1 ; Turn off
G4 P150
M42 P45 S0
G4 P150
M42 P45 S1
G4 P150
M42 P45 S0
G4 P150
M42 P45 S1
G4 P150

M42 P45 S0
G4 P3550 ; 7 pulses - Reset Chameleon
M42 P45 S1
G4 S3 ; Give 3 seconds to home

;Preheat Extruder
M109 S205

;Select 0
M42 P45 S0 ; Set
G4 P550 ; 1 Pulse
M42 P45 S1 ; Release
G4 P150

M42 P45 S0 ; Set
G4 P21200 ; 21.2 seconds
G0 E25 F2100; <<<--- adjust this E value to tune extruder loading
M42 P45 S1 ; Release
G4 P400
G0 E60 F2000

M117 Filament Loaded
G4 S10

; Now Unload it
G91 ; move to relative mode

; back out the filament for cutting
G0 E5 F1500
G0 E-60 F1500 ; retract a bit, adjust this to tune waste

;******* Auto UnderClippy Code ********

; Cut Filament and Unload
M42 P45 S0 ; Set
G4 P3050 ; 6 Pulses
M42 P45 S1 ; Release
G4 S2 ; Wait for cutter to clear

; ******* End UnderClippy Code

G92 E0
G0 E10 F1500; <<<---- if mechanical cutter, change to a positive value of at least 5mm
G0 E-60 F1500; Total back out of 90mm (+5)
G92 E0

M42 P45 S0 ; Set
G4 P21200 ; 3D Chameleon Retract
M42 P45 S1 ; Release

M140 S0 ; turn off hotend

It usually fails at Select 0. Having successfully reset the 3D Chameleon and heated the nozzle, although sometimes fails at Reset as I said before.

I'm curious if adding a pull-up resistor at the 3D Chameleon connector might help. It is a rather long cable...

3 comments

3 Comments

Bill

Jul 04

You can certainly add a resistor... but I'd also make sure you also have the ground pins tied together as well as make sure you're setting the pin state in the Start GCode. I'm also seeing something odd, but it must be correct, but your pin states appear to be backwards... normally pulling it to ground (with S0) is what sets it high... and setting it to S1 (or S255) sets it low. If that's the case, and you're running Klipper, it also might need to be set in the config file.

Since you're running purely digital, you can actually increase the time to something like 650 for the first long press for T0... and then add 400 for each subsequent pulse. That way it doesn't miss a cycle... the program loop has a natural 50 ms delay in it... and depending where it is in that window, at 450, it can actually miss the first pulse. So, 650, 1050, 1450, 1850 might be better numbers. The windows are 400 wide, so anywhere between 400-800 will be in the middle... with the 50ms offset, your valid range for the first pulse is 450+ to 800.

Bill

las_vegas

Jul 04

Replying to

So by that math, 7 pulses would be 6*400+650=3050? That time reliably gives me 6 pulses; Or am I confused? I'm running Marlin. The seemingly reversed logic seemed odd to me at first, but pulling it to ground with S1 has always triggered the pulses. The grounds are tied together, but not the Vcc.

Bill

Jul 04

Replying to

Ok... so you're running Marlin, so the bit is flipped, which is normal for it. As for your math, I guess I wasn't clear enough.... you need 450 * 6... there's 400 for the timing and 50 for the delay between each instance.

So, I think it should be 6*(400+50)+650=3350. Which is what your code is showing. So, where's the delta here... if that's not working, perhaps you need to increase the 400, as one of the two clocks isn't exact. My guess is the machine running Marlin might have a different clock speed... which could be causing the issue. (The G4 is processed by Marlin, and if it's not accurate, then all bets are off, if that makes sense.)

I'd play with just the 400 value above and see if that helps it. You can write a simple script that does 1 pulse, 2 pulses, 3 pulses, etc, all the way through 10. And after each one, do three quick taps of 150ms 3 times to reset them. Then you can easily feel it to see where it fails.

Bill