End stops pins not responding

Hello forum,

I recently built a prusa mendel like reprap with a sanguinololu 1.3a and three mechanical endstops.
I can upload the firmware (repetier) and control the motors through pronterface (but only in one direction). The endstops however are not responding at all. When I send the m119 command, they are all high (or low, if I invert them through the firmware). Connecting or disconnecting the pins on the sanguinololu manually doesn't make any difference either, so I guess it has something to do with my firmware settings or board, and not with the actual switches.
How should I proceed? Could it be that the pins are not configured correctly in the firmware?

Thanks in advance!

P.S. here are some possibly relevant configuration settings:

#define MOTHERBOARD 62

// ################ Endstop configuration #####################

#define ENDSTOP_PULLUP_X_MIN true
#define ENDSTOP_X_MIN_INVERTING true
#define MIN_HARDWARE_ENDSTOP_X true
#define ENDSTOP_PULLUP_Y_MIN true
#define ENDSTOP_Y_MIN_INVERTING true
#define MIN_HARDWARE_ENDSTOP_Y true
#define ENDSTOP_PULLUP_Z_MIN true
#define ENDSTOP_Z_MIN_INVERTING true
#define MIN_HARDWARE_ENDSTOP_Z true
#define ENDSTOP_PULLUP_X_MAX true
#define ENDSTOP_X_MAX_INVERTING false
#define MAX_HARDWARE_ENDSTOP_X false
#define ENDSTOP_PULLUP_Y_MAX true
#define ENDSTOP_Y_MAX_INVERTING false
#define MAX_HARDWARE_ENDSTOP_Y false
#define ENDSTOP_PULLUP_Z_MAX true
#define ENDSTOP_Z_MAX_INVERTING false
#define MAX_HARDWARE_ENDSTOP_Z false
#define max_software_endstop_r true

#define min_software_endstop_x false
#define min_software_endstop_y false
#define min_software_endstop_z false
#define max_software_endstop_x true
#define max_software_endstop_y true
#define max_software_endstop_z true
#define ENDSTOP_X_BACK_MOVE 5
#define ENDSTOP_Y_BACK_MOVE 5
#define ENDSTOP_Z_BACK_MOVE 1
#define ENDSTOP_X_RETEST_REDUCTION_FACTOR 3
#define ENDSTOP_Y_RETEST_REDUCTION_FACTOR 3
#define ENDSTOP_Z_RETEST_REDUCTION_FACTOR 3
#define ENDSTOP_X_BACK_ON_HOME 1
#define ENDSTOP_Y_BACK_ON_HOME 1
#define ENDSTOP_Z_BACK_ON_HOME 0
#define ALWAYS_CHECK_ENDSTOPS 1

A small update:
I read that the firmware of the sanguinololu needs a specific fuse setting. I got the chip with firmware installed, is there any way I can check these settings?
Burning a new bootloader with correct settings might be the best solution, but then I need to buy an oscillator and other components. I'd like to solve this problem without burning a bootloader if possible.

Yes. Check your firmware, or reburn. Also, the Sanguinololu endstop connects have 3 pins. Make sure your wires are on the outside 2 of each. (middle pin is unused). [reprap.org]

On a mechanical switch, there isn't a + or - wire, so there is no backwards. Check that both wires are leading to the same endstop. Finally check your soldering and test your wires. If all is good then you can test your switch by puting it between a bulb and power source. (such as a flashlight)

Thank you for your reply,

I have measured all cables and switches, everything seems to work, but the sanguinololu doesn't process the signal.
I'll have to reburn the firmware then. Is there a way I can do this without connecting an oscillator etc.? Otherwise, I'd have to buy one first.

Turn off mains power to your board. Plug your USB into the board and your computer. The LED should light up and your computer should install the new hardware plugged in. Using the Arduino IDE you can upload your configuration.h file directly.

Start here [reprap.org] at firmware.

If you think you may have corrupted your configuration.h file then download a new copy and start your calibrations all over again.

Edited 1 time(s). Last edit at 01/29/2014 08:51PM by KingRahl.