Gen7 1.5 questions

Hi,

I built Gen7 1.5 and doing checks as described on Gen7 1.4.1 page, there are few possible issues. I want to make sure everything is OK before plugging in ATmega. These are the 'issues':

1. ATmega pin 14 is high. I assume this is OK since it is connected to TX pin of MCP2200.
2. ATmega pin 7 is ~1.1V, is this ok? I thought all the pins should be below 0.5V unless at 5V.
3. All my 5V measure as 5.8V, not sure if it is power supply (using PC power supply) or something else. Is this ok?

I was able to connect the board to my PC using USB, so this seems to be OK. After changing configuration of MCP2200 using config utility, also LEDs (actualy, I could see only 1 since no ATmega plugged in yet) seem to be working.

Thanks,
Erik

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I was able to connect the board to my PC using USB, so this seems to be OK.

Honestly, it's a relief to read this. The same worked for me three times without failure, so I released the design, but would it work for everybody? Apparently yes, and I'm happy with it.

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1. ATmega pin 14 is high. I assume this is OK since it is connected to TX pin of MCP2200.

That's expected. That's MCP2200's TxD, also ATmegas RxD. Unlike with v1.4 you have signals on the board before inserting the ATmega.

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2. ATmega pin 7 is ~1.1V, is this ok? I thought all the pins should be below 0.5V unless at 5V.

Unless you have a programmer plugged in, pin 7 shouldn't be connected to anything. I'd double check this, but it also could be a static load, especially if these 1.1V dwindle while measuring.

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3. All my 5V measure as 5.8V, not sure if it is power supply (using PC power supply) or something else. Is this ok?

5V Standby in ATX supplies isn't as stable/precise as the main 5V. 5.8V is a bit on the high side, but no surprise here.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

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I was able to connect the board to my PC using
USB, so this seems to be OK.

Honestly, it's a relief to read this. The same
worked for me three times without failure, so I
released the design, but would it work for
everybody? Apparently yes, and I'm happy with it.

Even more good news :-) I was able to upload firmware using USB.

Quote

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2. ATmega pin 7 is ~1.1V, is this ok? I thought
all the pins should be below 0.5V unless at 5V.

Unless you have a programmer plugged in, pin 7
shouldn't be connected to anything. I'd double
check this, but it also could be a static load,
especially if these 1.1V dwindle while measuring.

I decided to give it a try and it seems to be working fine...

Hi there and sorry to pick up this rather old thread, but I've got a question linked to those asked here before...

I'm assembling A Gen7 1.5, too.

After having soldered everything but the Mosfets, I proceeded to the power supply checks.
Everything is how described on this page (http://reprap.org/wiki/Gen7_Board-AVR_1.5), except:
.) Pin 14 of ATmega is at 5V
.) Pin 15 of ATmega is at ~1.1V

I just wanted to ask if that's normal, before blowing up the ATmega.

Thanks in advance.

Regards,
Markus

Edited 1 time(s). Last edit at 05/12/2013 10:04AM by markus3D.

Yes, this is normal, because the MCP2200 is already working. You're measuring RxD and TxD of the serial line.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Thanks alot.
Soldered the Mosfets, connected the ATmega and lit the whole! ... no smoke until now.

Looking forward to connect the board to PC...

Thanks again.