Upgrading older OTGW by exchanging P16F628 for P16F88 ?

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Upgrading older OTGW by exchanging P16F628 for P16F88 ?

Postby ThinkPad » Thu Oct 22, 2015 9:17 am

Hi,

I got a OTGW from Digit a while ago. It works fine, but when i start it up, it presents itself as "OpenTherm gateway 2.0"... so it is really old when i see that on the OTGW website firmware 4.0 is available.
However my OTGW uses the older P16F628 + 4Mhz crystal so i can't upgrade to the newer firmwares meant for the 16F88 i guess...

Would it be possible to exchange the 16F628 for the newer 16F88 so i am up to date again? Or has the PCB / components also changed between the versions?
I don't mind a bit of soldering.
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Re: Upgrading older OTGW by exchanging P16F628 for P16F88 ?

Postby hvxl » Thu Oct 22, 2015 8:27 pm

The biggest problem is that the serial interface is on different pins on the two PICs. Pin 8 is TX on the 628, while it is RX on the 88. RX on the 628 is on pin 7 and TX on the 88 is on pin 11. You would have to shuffle those connections around. Other than that, there is nothing that I can think of off the top of my head that needs changing. Even though the boiler interface is different, it uses the same inputs and outputs. So that should still work together with a PIC16F88.

Clearly this is all purely theoretical, so I'm not giving any guarantees that it will actually work with the mentioned changes. But I give it a pretty good chance.
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Re: Upgrading older OTGW by exchanging P16F628 for P16F88 ?

Postby ThinkPad » Fri Oct 23, 2015 7:35 am

Good to know, thanks.

I'm not sure about exchanging the PIC, but first wanted to ask here :) After all the only thing i do with it is monitoring the efficiency of my HR-boiler: http://tweaken.blogspot.nl/2015/01/cv-k ... t-een.html which now works fine, i am only gathering data, for adjusting setpoint and such i have a Honeywell Round Connected Modulation (with app on smartphone).
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Re: Upgrading older OTGW by exchanging P16F628 for P16F88 ?

Postby ThinkPad » Fri Oct 23, 2015 3:31 pm

By the way, in Domoticz the OTGW says:
Code: Select all
2015-10-23 16:29:39.931 OTGW: OK
2015-10-23 16:29:39.931 OTGW: PF


Where does the 'PF' stand for? I couldn't find it on the OTGW website.
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Re: Upgrading older OTGW by exchanging P16F628 for P16F88 ?

Postby hvxl » Sat Oct 24, 2015 8:15 pm

As you're still using an old model gateway, you should get your information from the old web site.
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Re: Upgrading older OTGW by exchanging P16F628 for P16F88 ?

Postby ThinkPad » Mon Nov 02, 2015 11:07 am

Thanks, didn't know about the existence of that version of the website.

I decided to buy a new PCB & PIC & some other components. The 'expensive' parts like the transformer can be used again, so i will desolder them from my old OTGW and reuse them, #savetheenvironment
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