Custom arduino board has 1V ground

Other Hardware General Electronics
1

I started making a protoboard prototype of a device that uses arduino mega. Then I integrated what I had in the protoboard, with the available schematic of the arduino mega in a KiCad board design, and had it manufactured.

I couldn't board the boot-loader albeit the other components in the board worked well (i.e. addressable led's). While troubleshooting, I measured the clock pins. In a healthy arduino uno, I saw that there was a 1volt oscillation starting at 0v. Then, I measured my custom board, and the oscillation is the same, only that it starts at 1v. No wonder why I couldn't burn bootloader. I was powering the bricked arduino with a healthy arduino uno, pin to pin.

--edit--
I discovered in many other points of the board, ground is 1V despite it is connected pin-by pin to an arduino uno whose voltage levels are ok. They are hooked up via the 6-pin ISCP (MOSI, MISO, 6V, SCL, GND, SS)
--end edit--

I am tying to figure out what was my mistake, perhaps with some jumper wires I could correct it.

I attached the crystal section of my schematic, and photos of the oscilloscopes. I know little what could be the cause, so I don't know what else to attach.

my crystal datasheet: https://statics3.seeedstudio.com/images/opl/datasheet/306010014.pdf
C8 and C9 datasheets: https://statics3.seeedstudio.com/images/opl/datasheet/302010018.pdf

thanks for checking this!

question schematic.PNG
question schematic.PNG1040×650 6.95 KB

question osc.jpg
question osc.jpg600×800 106 KB

2

Ok, I realized what happened, and I post it here in case somebody has the same problem:

My ISP cable was wrong, or I am not understanding how these cables work. Basically, I needed to mirror all the wiring in the longitudinal plane. In other words, flip connectors 1 with 2, flip 3 with 4, etc. I hope I didn't fry my arduino having it plugged the wrong way for some time. At least there was no heat nor smell. My wrong connection caused me to connect uno's 5v to MISO, and vice-versa; SPI_SCK to MOSI and vice-versa, and RESET to GND and vice-versa. Doesn't look too bad. It is tricky to mentally flip all the connections, specially because the connector is in the back side of my board, so I have to flip it one additional time when thinking how to connect it.