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[ASJ]

Hi
I am returning to astronomy after a break of about 5 years and obviously In that time a lot has changed.
I have an AstroEQ that I built in 2013, it is V4.0 hardware with A4988 motor drivers and I think version 5.4 software.
Just recently I was considering how I could build a simple hand controller to drive the stepper motors and provide basic tracking without a PC when I discovered that this is now an option with AstroEQ.
I have read the tutorial about adding the ST-4 port to the V4.0 hardware (seems simple enough), but before I go doing anything brash, I wanted to check whether my hardware supports the latest firmware and if I can simply use the configuration utility to update it. (The configuration utility didn't exist when i built my controller!)
I noticed there is a comment about legacy hardware for V7.0 in the version history but the link didn't work, so I don't know its significance.
Finally My "Astronomy" laptop is operating on windows XP, I understand that the configuration utility itself needs Vista or later which is ok as I can use my desktop PC for that (which is windows 10), but will My AstroEq work with the XP laptop after the update?
Many Thanks,
Alex

[TCWORLD]

Hi Alex,

Welcome back.

Thanks for spotting the dead link on the downloads page, I've fixed it. In any case, that was just for Arduino Mega based boards, so doesn't apply here.

In terms of getting your V4.0 to work with the latest firmware, there are a couple of required changes.

• The addition of an ST-4 connector.
• A new 1k resistor is required to be connected between pins 12 and 31 of the ATMega (IC1). (see quote below)

I believe you've found pictures of the conversion already, however in those pictures, it shows a conversion with just the 4 direction pins connected. This was changed slightly in later versions, so you'll need to wire up slightly differently if you want to be able to use the hand controller.

I've attached two pictures. The first shows the pinout of the ST-4 connector, which is basically the same as the ubiquous ST4 pinout, with the only difference being the otherwise unconnected pin 1 is used for speed selection.

The second shows the connections that must be made to the AstroEQ board. The six pins on the connector must be soldered to the corresponding microcontroller pins (note this is a top down view, make sure to flip it if looking at the bottom of the board).

Additionally as shown in the second picture, a 1k resistor must be connected between pins 31 and 12 of the ATMega. Without this resistor the AstroEQ will be unable to talk to EQMOD or the config utility as it will jump into standalone/handcontroller mode.

Once those changes have been made, you'll be able to update the controller to the latest version of the firmware. You'll be able to use your modified controller with either A4988/A4983 drivers or DRV8824/DRV8825 drivers. You won't be able to use the TMCxxx or DRV8834 drivers.


In terms of Windows XP, the you won't be able to run the configuration utility, you'll have to do that on another computer.  This only has to be used when making changes to the configuration or updating the firmware. It's not required when using EQMOD. Once the controller is updated you'll be able to connect it back up to your existing XP setup and it will work fine.


If you have any problems, let me know. As it happens I have an old V4.0 board sat on my desk (purely for nostalgia), so if anything goes wrong we should be able to get you back up and running.

Kind Regards,
Tom.

Hi Henk,

V4.3 hardware is possibly the issue. In the later hardware versions there was a resistor added which is used for hand controller detection. Without this resistor the new firmware will not be able to run detection properly and incorrectly switch into push-button mode.

To remedy this, you'll need to add a 1K resistor pins 12 and 31 of the ATMega162 (IC1) which should allow the older hardware to support the newer firmware.
If your board has the ST-4 connector attached, you should also solder a wire between pin 12 of the ATMega162 and pin 1 of the ST-4 connector (the pin closest to JP2 on the board).

[ASJ]

Hi Tom,
Thanks for the info. Just to make sure I understand you correctly, all I need to do is add a 1K resistor between pins 12 & 31 of the ATMega, and connect pin1 of the RJ11 ST-4 port also to pin 12 of the ATMega, and the rest is the same as the tutorials?

Thanks,
Alex

[TCWORLD]

That all looks correct.

Tom.

[ASJ]

Hi Tom,
I've modified the board to add the ST-4 Port, and successfully updated the firmware using the configuration utility, but when i try to configure the board in the next step, it fails to read the EEPROM, giving the message "Read Failed!! Connection unavailable". The status light blinks slowly during the read attempt but after a while it seems to time out and give the error message. I am using V8.17 of the configuration utility tool. Any ideas what the problem could be?
Thanks
Alex

[TCWORLD]

If the status light is blinking slowly, it means its gone into hand-controller mode, which happens when the "speed" signal is shorted to ground.

Could you check that the white wire at the connector end doesn't short to the ground plane or ground wire.

If no shorts, try a power cycle of the AstroEQ and see if the status light stops blinking continuously.

[ASJ]

Hi Tom,
I've checked for shorts on the white wire and haven't found any. The sequence i'm getting is as follows:
Connect power: Power led lights solid, status led lights solid.
Connect USB: USB led flashing, status led blinks rapidly then returns to solid.
Open config utility tool and set com port and firmware type, click configure: status blinks rapidly then slowly (5s on - 5s off) as it attempts to read the EEPROM. Eventually blinks rapidly again when the EEPROM read times out and the failure message shows.
i'v removed the EEPROM chip to look for damage  / corrosion on any of the pins, and looked for dry joints but all to no avail.
i have re flashed the firmware again which said it was successful and reset the power, but still the EEPROM read fails.
I've read a post where someone was having a similar problem and managed to get success with an earlier version of the firmware, might that be a solution?

Incidentally, I have no real need to change anything in the configuration other than to set the ST4 rate for the hand controller. The basic configuration "should" still be the same as it was last time i used it (albeit about 5 years ago) unless anything has changed in that time that would require a re-configuration? It would be nice if I could get it to work though.
Thanks.
Alex

[TCWORLD]

Hi Alex,

Think I've found a mistake in the firmwares handling of the state your controller will be in.

Could you try the attached firmware - just pop it in the hex/ folder of the config utility and update firmware again.

Kind Regards,
Tom.

[ASJ]

Many thanks Tom, That seems to have done the trick, at least as far as the configuration utility goes, (I've yet to try it on the mount).
One more question about the config, do I need to enable the Advanced H/C option? it says it is only for v4.6 boards with the resistor mod, is that 1K between pins 12 & 31 that i did?
Thanks
Alex

[TCWORLD]

Hi Alex,

Glad that's fixed it. I'll release that version of the firmware to prevent others having the same issue.

For the advanced H/C option, the 1k resistor is indeed the resistor mod, so if enabled, it will work as intended. At the moment it doesn't really matter if its disabled as I never got around to developing the planned advanced handcontroller.

Kind Regards
Tom.

[ASJ]

Hi Tom,
Spoke too soon i'm afraid!
I tried the controller with my hand controller, just to see if that worked but it didn't, the switch doesn't seem to change anything, i cant get go-to speed and i have no DEC control at all. thinking this may be because i set the go-to speed too high, i went back to the configuration tool and the EEPROM read failed again. Tried re-flashing the firmware again (which succeeded) but still failed the EEPROM read. This time however the status LED is flashing at about the same rate as the usb one.
Not sure if my hand controller has done something dodgy, ive put a picture of the circuit for reference.
Thanks
Alex

[TCWORLD]

Hi Alex,

Make sure the hand controller is not plugged in when running the config utility.

If the hand controller is plugged in, and the speed switch is set to ground, it will immediately enter hand controller mode, at which point it ignores the serial port until the next power cycle. The config utility wont be able to talk to it in hand controller mode.

If you've got a multimeter, I'd probe all of the buttons to check that the signal pins are high when not pressed, and go low once the buttons are pressed. Let me know how that goes.

Tom

[TCWORLD]

For speed selection, you may have to try adjusting the resistor value. The controllers will have different internal pull-up resistance which can have an impact on the speed sensing process - that's the main reason I didn't sell any of the ones I got made. A potentiometer could with this.

[ASJ]

Hi Tom,
This morning, before trying any of your suggestions, I had another try of the hand controller, just to double check the symptoms, and it worked fine! I was able to switch between the 3 speed modes, all four direction buttons worked as expected. The only thing I did differently was this time I had the speed switch in the go-to position when I powered up the board then switched to ST-4. Previously I powered the board up with the switch already in ST-4 Mode, which I assume caused it to initialise incorrectly.

I did find however that the RA motor ran out of torque under go-to, with the rate set at x668 and 16uStep (I deduced this from the fact that the Dec motor is fine at x689 but is only running at half the speed due to the higher worm ratio.). So decided that a lower RA go-to rate would increase the motor torque and likely solve the problem.
I ran the configuration utility again and it read the EEPROM fine!

So it would seem that powering the board with the switch in the ST-4 mode somehow locked it in stand alone mode. I don't understand why the power cycle didn't solve this yesterday though? Does this make sense to you?

One more question about the configuration utility, what should the GPIO1 drive type be set to? I have left it at the default "Push-Pull".

Thanks
Alex

EDIT, one thing I have just noticed is that whilst it does read the EEPROM and load the existing configuration, the gear ratio settings are all blank. The calculated values are still there but the setting fields are empty, and if you hit the update button it clears all the calculations. Its not a problem as I always save my configurations so i can recall them later but thought it might be a bug in the configurator.

[TCWORLD]

Hi Alex,

The EEPROM only stores the calculated values, so it can't restore the original entered values. It's annoying, but you only need to press the "calculate" buttons if you are changing the gear ratios, the driver type, or the microstepping mode. Changing the goto speed, or ST4 speed etc don't require clicking calculate, so it doesn't matter if the corresponding fields are empty.

You can ignore the GPIO1 setting as you won't have that wired out anywhere. I can give further details if you need them - it allows you to use the "Snap" pin control in the latest version of EQMOD (V2+).


A power cycle should be enough to get the controller out of hand controller mode, unless the handcontroller is still plugged in, at which point it will re-detect it if the speed pin is not floating. So if you had it set to ST4-speed, it would re-enter handcontroller mode on power up. Sometimes having it set to 2x speed will also cause it to enter handcontroller mode.

It's possible a loose connection was causing it to not work properly the first time out, but not sure. I'll have a look through the code when I get the chance to see if there is a bug somewhere in initialisation.

Kind Regards,
Tom