Anyone here using Marlin 1.0.0, RAMPS 1.4 and Radio Control Servos?

3D Printing
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Anyone here using Marlin 1.0.0, RAMPS 1.4 and Radio Control Servos?

I wanted to test things out with my spare electronics and a servo before changing my Kossel Mini z-probe setup. I’ve got a jumper added to the RAMPS so the servos get power, uncommented #define NUM_SERVOS in Configuration.h and uploaded the code, power cycled, etc.

It’s responding to M280 commands, letting me set a position between 0 and 180 and read it back. But I don’t see anything on any of the PWM pins that would cause servos to turn. I’ve hooked my 'scope up to it, 0 volts, not a hint of a frequency.

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Did you check the “Servo Option notes” in the readme at https://github.com/ErikZalm/Marlin/tree/Development?
There are 2 more options, not sure of they are required, though. After you defined those, you should be able to switch between the positions with M401 and M402.

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I did. If I uncomment
#define SERVO_ENDSTOPS {-1, -1, 0}// #define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0}
then it won’t even compile the sketch, I get an error “expected primary-expression before ‘{’ token” re Marlin_main.cpp: In function ‘void homeaxis(int)’. error: expected ‘)’ before ‘{’ token. There is a ) before {.

I was hoping to be able to at least turn the servo with M280.

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Just upgraded to the Beta Arduino software 1.5.8, it gives more info about the error. Looks like it’s the #define in Configuration.h that’s the problem rather than Marlin_main.cpp…

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Dropped the #define statements and added
const int SERVO_ENDSTOPS[]= { -1, -1, 0 };
const int SERVO_ENDSTOP_ANGLES[]= { 0, 0, 0, 0, 70 ,0 };
to marlin_main.cpp. It compiles without issues. Still no output on the PWM ports. I wonder if it could be the RAMPS1.4 or Arduino? @Think3dPrint3d have you done anything with RC Servos? I’m running Marlin_Kossel_T3P3_20140805.

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Not touched the servo code at all. You might want to try running a simple servo sketch to confirm the firmware vs hardware issue.

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Hm, the latest stable compiled ok for me with those defines in Arduino 1.0.6

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I’m not trying to run 1.0.1 yet, still at 1.0.0. I’ll try a simple servo sketch. It that works I’ll have a go at migrating changes in 1.0.0 for the T3DP3D Kossel Mini to 1.0.1

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Thanks for the simple sketch idea @Think3dPrint3d , it didn’t work first time, I found a forum post that mentioned the pin mappings for the servos with RAMPS 1.4 (11,6,5,4), changed 9 to 11 and the sketch started working. Checking the Marlin code I found lines including things like defined(SERVO0_PIN). A single line added to pins.h and it’s all working :smiley:

#define SERVO0_PIN 11