10/28/2025 - Designed custom H3 symbol

So, I've made a custom H3 symbol & footprint (First part of it). Took quite some time as I needed to manually place all the pins on the thingy so I had to do the thing.

10/29/2025 11 AM - Drew DDR3 and started routing

Drew DDR3 schematic and started routing it! Goal is 4 layer pcb w/ low cost. Not much to explain here if you need more info go to google or eevblog forum.

10/29/2025 9 PM - Routing DDR3

Doin' more work! Routing the DDR3 right now and it's becoming soo much cleaner. Wanted to do a dual rank ddr but oh well one step at a time. This is now way harder than FPGAs as well yk the pins r set

10/31/2025 4 PM - Continued to route DDR3

Continued to route DDR3, routed out a lot of data lines and all of the address lines. Currently it's also looking a lot cleaner than what I hade before this.

10/31/2025 10 PM - Length matched DDR3

Sooo guess what, the DDR3 is routed and length matched! Am proud of the design and happy about what I did. Nothing else to say in this stupid devloge.

11/1/2025 - Added support for 1GB of RAM

Added support for 1GB of ram and length tuned a few missed trace. Nothing else to say that's why I hate this word count ugh. Like common just get to the thing

11/2/2025 12 PM - Drew more symbols and footprints

Sooo,,, drew some more custom symbols and footprints, drew schematic for gpdi and wifi and bluetooth. Quite easy imo but took some time to do this....

11/2/2025 6 PM - Rerouted DDR3

Soooo I've done it,,, re-routed the fucking entire DDR3 to follow the 3W rule and generally become better. L4 also got swapped with L3 for better things

11/3/2025 9 AM - Re-match DDR3 for the 3rd time

Re-matched the traces yet again
This time moved L3 to the back again (Or else the clock trace won't work out) and changed up some data pairs for generally cleaner routing

11/3/2025 9 PM - Drew USB schematic

Drew USB schematic with all the ports needed for this compute module that I am making . Also had to draw a few more custom footprints and symbols ugh.

11/4/2025 - Decoupled ddr3 and drew foorprint

Placed decoupling caps for my DDR3 memory:

Also drew a custom RJ45 ethernet connector footprint for future use.

Nothing more, did this tonight after school.

11/5/2025 - Expanded RF and added tvs

Expanded the RF section by a bit

Also added some TVS diodes

A lot of the symbols r custom symbols that I drew by myself in the symbol editor of kicad ide.

11/6/2025 - Drew eMMC, sdcard and schematic

Drew eMMC & more H3 symbol, sdcard footprint and routed out a bit more of the schematic, this took quite a while ugh...... I'm tired now, but this gotta continue

11/8/2025 - Layed out PCB

Added some GPIO, Audio I/O and layed out the board for future reference, only power and a bit more of drawing the H3 symbol left and I'll start rotuign

11/9/2025 - Drew large part of DC DC converters

Drew the most of the power lanes. Also drew a power distribution schematic for easier viewing. This was hard to determine tbh, still got quite some work.

11/10/2025 - Decoupled CPU

Added quite a bit of decoupling and started to route things out. The stuff around the CPU is truly starting to take shape. Final product should be done soon.

11/11/2025 - Decoupling on pcb!

Decoupled a bunch, improved schematic & also calculated the inductor values. I also switched around the models of the dcdc converters to get better inductors.

11/12/2025 - More routing

Routed even more of the board and some of the DCDC converters. Notably the EPHY and SD card connector, but also some other stuff that you see on the pcb

11/13/2025 - Placed buck converters and routed

Did a lot more routing, placed buck converters, improved layout and all kinds of routing. Nothing more to say so fuck this stupid word count that is stupid

11/15/2025 6 PM - Almost finished...

Soooo,,,, yep, routed all this out,,,
5k tracks, 1.4k pads and ~600 vias
Now only some ground stitching, 2 leds and GPIO left... And need to do a small pass on reference continuities...

11/15/2025 10 PM - Finished da PCB

Soo... I finished it! Routed out some of the gpio, but some others are like plain stuck inside so I'm not even gonna bother. Routing em out will likely require a total respin.

12/12/2025 - Ordered the PCB

I'll need to reverse journal a bit

First I did a few new fixes to the design, like shrinking the inner pwr plane and improving the routing, mitigating power splits and improving signal integrity. Also re-checked the entire design, like my power H3 custom symbol and footprint.

Took quite a bit of time as I had to well re-check everything

Also bom optimized a ton! Merged resistors, caps and more

12/20/2025 - Debugging

Welp I've been debugging quite a bit:

Somehow it wasn't booting up, and I spent way too long looking at the schematic and probing around... Welp turns out that somehow I messed up the crystal's CL and it wasn't oscillating. So I bridged on a crystal oscillator

Now the usb is being detected but well it isn't correctly being enumerated :c

12/22/2025 - Finished the firmware

Welp so I did a lot more debugging... Soldered on crystal oscillators on multiple boards, did some reflow soldering and then discovered I actually scrambled a ram...

I've also made a custom USB cable and finally got it to show up as a fel device. Then I dug hard into allwinner's software, which was a goddamn mess. Had to download official (?) tools from 3rd parties. But I got the ram working!

Then after a lot of other work and kernel compiling, I got linux & android running on the board:

wasted two whole days on this....