PD7 problem at ATmega644/ RESOLVED

[eldeejay]

Good morning, I have a problem with the ATmega644 microcontroller and the output pin PD7 (p1d2).
This output is activated to give the direction of rotation. Well, with PD7 not connected to anything, test PD7 with the oscilloscope and the signal is perfect (5V - noise = 0).



But just to connect a single cable for communication with the MOSFET power circuit, the signal changes, properly triggered 5v level but there is a noise.



And to connect PD7 with the input of the AND gate (74HC08) the signal drops to 1V.



I tried to connect the output PD7 with different loads, such as an LED, or a simple resistance PULL-DOWN and always produces the same problem, the signal drops to 1 volt. I have also tried several microcontrollers and the effect is identical, the signal drops to 1 volt. I even tried to optocoupled output with a 4N26 and the effect is the same. I have reviewed the Atmega644 datasheet and no specific references to PD7, or at least that I've ever seen.

The rest of the microcontroller inputs and outputs are working properly.

Has anyone has this problem occurred? Can anyone help me with this illogical behavior?

Greetings and thanks in advance

[prilad]

But just to connect a single cable for communication with the MOSFET power circuit, the signal changes, properly triggered 5v level but there is a noise.

Hi, eldeejay

Are you checked cable on short-circuit between wires?
Are you have the same problem with another cable?

Regards...

[eldeejay]

Hi!!
Yes i checked for short and i have and use more new wires.
Thanks for your help

Regards

[tronicgr]

Hi eldeejay,

I don't recognize this board. Is it your design? Does it have its outputs compatible with AMC1.6??

I need to know some things about it before I can help. Is it running AMC1.6 firmware? What version? Some beta versions had problem with the direction pins (including PD7)

The problem you describe looks like internal pull-up failure. Maybe you connected load bigger than 20mA and burned something.

The noise problem comes from the PWM lines next to it since you left it floating on the cable.

Thanos

[eldeejay]

Hi Thanos,
Yes, it is my own design and is based on his work, but is fully compatible with the outputs of the AMC1.6. The firmware I'm using is for the ATmega644 you had published in June / 12 Version 1.1
As for the burden, I assure you I have not exceeded at any time 20mA. I made ​​several test to understand the stability of the output PD7, but when I connect to any element falls (start input of the 74HC08 AND, I've also tried to put a led, and I've also tried to put a simple resistor 10K PULL-DOWN mode - that is with reference gnd).

Are the outputs PD2 - PD7 have pull-up resistors enabled by software?
In my design the power circuit for the engines, I have included polarization resistances at the inputs of the 74HC08 logic gates for PD2, PD3, PD6, PD7. These entries are unstable and dangerous if they are not polarized, but this rectification does not interfere in any case where the operation of signals, is an improvement without any negative repercussions.

Thanks for your help and your work Thanos

When my developments are 100% operational, will share in the forum.

Regards

[tronicgr]

Did you try to use the latest firmware? The one of June12 /1.1 is buggy.

FTISP for AMC1.6 v1.1e.zip

Thanos

[eldeejay]

I have not tried yet, I'll download it and try to see if it improves.
I will comment the results, thanks.

[eldeejay]

Hi all,
Today I tested the latest version of firmware 1.1e, problem solved. The PD7 pin ATmega644 microcontroller and is stable and has a perfect logic signal.
In the previous firmware version should have a problem config PD7 output port.


Thanks Thanos

[tronicgr]

I'm glad it was resolved.

I update that project page once or twice a week, adding new information there, or firmware updates. So, bother to go through the first post at least once a week, to keep up with the changes. I bet no-one noticed the new links I put there to some cheap knock-offs of the FT232RL board I found on ebay


Thanos

[motiondave]

I'm glad it was resolved.

I update that project page once or twice a week, adding new information there, or firmware updates. So, bother to go through the first post at least once a week, to keep up with the changes. I bet no-one noticed the new links I put there to some cheap knock-offs of the FT232RL board I found on ebay


Thanos

I am NOT bagging your product in anyway, I am willing to spend money on your product, so please see that clear.

Thanks for that, but really I need a COMPLETE list of parts, and really able to buy them in one place. A slight extra overall cost and the simplicity of ordering in one place is better than spending hours scouring the net for one part.
Surely there is one supplier that can be sourced, or at least a group of suppliers that have the parts as regular stock.
I am looking at this board as a next step, but if the parts list and pcb board are too hard to source and too high a price , I may as well go the K8055 - arcady or not.
My plan is to move up to 24 and then 240v motors. For that, I need a proper working control board and by that I mean RUNNING, not with parts , pcb or code issues.
Cheers, David.