Stuck testing DRV8825HW203

[David V. Dearden]

Robert,

Thanks for making this project available. I’m a complete newcomer to Arduino and am attempting to build the DRV8825_HW203 full option. I have the parts assembled and have run the buzzer+LED test and the temperature probe test successfully. However, when I try to run the BasicDRV8825HW203Test, I see the proper text output but nothing happens with the stepper motor (17HS13-0404S-PG27). Similarly, Test Program 5 gives the initial text output in the serial monitor and the LCD backlight is on (it comes on as soon as the system is powered), but nothing appears on the LCD.

I fumbled around enough getting started that I fear I may well have damaged something. So here are my questions:

1) Are there diagnostics I can run to verify I haven’t hurt the Nano or the DRV8825 board?
2) I assume I can simplify the system by removing things like the Power On/Reset circuit and the LCD. Is that right?
3) Am I running the correct test program (BasicDRV8825HW203Test)?

I'm at a loss what to try next, so any help would be greatly appreciated. Sorry to be such a novice.

Thanks!
David

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David V. Dearden
What I do for fun:
astrobin.com/users/dvdearden
deardencheapastro.blogspot.com/

[brownrb]

Hi David
Yes, there are things you can do.

To test if the nano works, use the "testnano.ino" program attached If there is no serial out its stuffed. Generally if you can still upload to a nano, then its probably working.

To test the LCD, use the attached program testprogram5.ino but you must install the lcd library which is also attached.

Check stepper motor wiring
PG5/27-BLACK - RS232-Pin4 goes to A2 of the DRV8825
PG5/27-GREEN - RS232-Pin3 goes to A1
PG5/27-BLUE - RS232-Pin1 goes to B1
PG5/27-RED - RS232-Pin2 goes to B2

To test the stepper motor
1. You musy have +5v on the nano board and 12V +ve on the DRV8825 to VMOT pin and 12V GND to the GND pin on the DRV8825, the ground on the 12V also wired to the ground on the Nano.
2. Check that the wires of the stepper motor are correct to drb8825 pins
3. turn on power to nano then turn on power 12v
4. Run test program BasicDRV8825HW203Test
5. If the stepper motor does not move
6. If you have a multimeter check value on EN pin of DRV8825 it should be GND or 0V. Check that there is 12V to DRV8825 - put red lead oof multimeter on VMOT and black lead of multimeter n GND, multimeter should read 12V, also check that RESET and SLEEP are at 5V
7. Try very slowly moving the pot on the DRV8825 board whilst BasicDRV8825HW203Test is running.

[David V. Dearden]

Robert,

Thanks for your quick reply. I've run the tests with these results:

1. nanotest.ino runs OK (I did have to change "void main()" to "void loop()" because I kept getting errors on compilation about int being expected). I'm pretty sure the Arduino itself is fine. Sketches load fine and the serial communications are as expected.
2. testprogram5.ino still gives me nothing. I tried with the jumper on the LED backlight pins (the LED backlight comes on when the jumper is in place) and without (I get no light). Turning the pot on the back makes the display background come on but it never reads "Focuser Test" (I just see rectangles) although I do see the messages in the serial monitor (but these seem to come up only when I'm handling the LCD board and flexing the pins on the back, making me wonder if some connection is bad). I verified that VCC is connected and I have 4.95 V between VCC and GND; I also checked that SDA is connected to A4 on the Arduino and SCL is connected to A5. The power light on the back of the board comes on when I power the Arduino board.
3. The motor still does not move, vibrate, or do anything. It just sits there. I checked each of the connections from the colored leads on the motor back to the A2, A1, B1, and B2 pins on the DRV8825. EN is at 2 mV. VMOT-GND is 11.55 V, and SLP and RST are both 4.96 V. Moving the pot on the DRV8825 board makes no change.

Maybe I damaged the motor? I think when I was initially trying to get it working the coils got warm (I was using the wrong motor test program at the time), but I may be imagining that. They certainly don't get warm now.

Thanks,
David

[brownrb]

HI David
1. The nano is ok
2. For the LCD, check the folder called LCD Issues and work through that to get the LCD working
3. For the motor - unlikely.
4. Wire mutlimeter (set to current ) in series with the stepper coil (either A or B). Load the firmware .ino back into the controller. Connect the usb to controller, start up windows application. turn on 12V to drv8825. Use windows app to connect to controller. Set coil power ON.
4. If its working and you turn the pot then you will see current vary. Turn pot till curent reads about 250mA
5. If no current, then one of 2 things : either drv8825 is stuffed (easily damaged if stepper is diconnected when 12V applied), or second: Wires on stepper motor are connected wrong?

You can use meter and measure between the stepper wire pairs to find out what the pairs are - put multimeter on one lead and test resistance to other three - only one of those should have low resistance, hence thats one pair and the other two wires are the other par - then wire one pair to the drv8825 A and other pair to drv8825 output B. Then try running code again, there are left only a limited number of combinations - ie swap the leads on A, if not ok swap leads on B - think of it as combinations of A normal _ B normal, A swapped B normal,, A swapeed B normal and finally A swapped and B swapped. EACH TIME WHEN CHANGIN WIRES MAKE SURE 12VDC TO DRV8825 IS OFF else drv8825 will be damaged

Cheers
Robert

[David V. Dearden]

Robert,

Still no luck.

In running the LCD parameter guesser, I never get a "device found" message. The comments at the top of the sketch said something about needing a pullup resistor for the I2C. Is that part of the MyFocuserPro circuit already? I also can't test with nothing else connected to the nano since it is already soldered to the stripboard with the rest of the MyFocuserpro components.

I wasn't able to connect to the nano with the Wjndows app; when I power up and connect the USB the buzzer and both LEDs come on but when I try to connect to the proper COM port I always get a timeout waiting for a reply to the "get firmware version" command so I can't make a connection to turn on the coil power.

Sorry to be such a novice, and thanks again for your help!

David

[brownrb]

Hi David
Ok so an option would be to leave LCD off for now. Pullups are not required
Please connect the LCD and then download and run the I2C scanner program. Let me know what it outputs. Then put the LCD to one side for now

Do the following tests with the controller connected via USB - not necessary to connect 12V

Ok when controller is connected power is on both leds should come on for about 1-2s then go off.

First: What is arduino firmware file you are using?
What is version of Windows app you are using?

That is unusual that you are getting a timeout. Connect the controller up via usb and then start the Arduino IDE that you used to program the nano controller. Open the serial port monitor wihtin the IDE and connect to correct com port and set to 9600.

The controller leds should come on then go off.

At the top line of the serial port window enter the command :GP# and hit enter key
System should display something like 1388#

Try sending :XY# which should display a lot of stuff

Let me know what happens.