Some questions

[krzak]

Great, but I think, however, first try of the 4051st I am not worried about the availability of BAT85, or other elements. I mean just that a large number components, and holes to be drilled. Pads are not large, and after drilling may be very small, making it difficult to solder. Maybe it would be possible to avoid increasing the pads.

[krzak]

The last question to finish on the choice of tiles version. If I had 74hc4851, then would you recommend the version with two boards? I ask because I wonder if you recommend it only because of the difficult availability of chips, or also for another reason?

[dmitri]

The PCBs from viewtopic.php?f=3&t=266 are developed and tested by me and match the up-to-date schematic. Ultimately it is up to you which PCB to choose, you can even take the schematic in the Kicad format from the same topic and develop your own PCB layout.

[krzak]

Is it necessary to use resistors with a tolerance of 1%, as some of the lists of components, or can I use resistors with a tolerance of 5%? Does the use of resistors with a power 0.125W, 0.25W, 0.5W is without a difference?

[krzak]

How should be set to the bit of security, and fuses in Avr Studio 4 for Atmega644 with 20Mhz crystal? Can I ask to screen with the correct selected?

If it has any meaning, it wants to say that I wants to upload last unencrypted firmware without a bootloader, which is not needed, because I can upload only one version of firmware.

[dmitri]

You could have search the forum and you would have found viewtopic.php?p=7281#p7281
Without a bootloader you can disable the BOOTRST fuse.

[krzak]

Yes I know, but thank you for your help. In that case I will not program the BOOTRST fuse if it's not necessary.

One more question, I should first set the fuses, or upload the firmware? Or is it not matter?

Regards.

[dmitri]

One more question, I should first set the fuses, or upload the firmware? Or is it not matter?

First firmware than fuses.

[krzak]

To make sure that every fuses is set correctly I put a screen.

I have a problem with the lock bits, because I do not know how to set them. Possibilities are in the attached picture.

[dmitri]

Fuses FC, 35, DF or FC, 35, D7
Lock bits leave as default, i.e. FF.