2021-05-08                         from the editor of ~insom
   ------------------------------------------------------------

   I have finally gotten two UARTs working from NetBSD on the
   Allwinner/sunxi V3s board that I bought from AliExpress. I
   purposely wanted to work with something more obscure and (at
   the same time) more mainstream than a Raspberry Pi.

   The Lichee Pi Zero (which is the board; honestly not much
   more than a breakout board and some regulators for the V3s
   chip) supports three UARTs and SPI and I2C. It also
   technically supports Ethernet via some interface that I am
   not (currently) interested in.

   I haven't used NetBSD in a very long time so in way this
   feels like retrocomputing -- which sounds like a diss
   against NetBSD but should not. Linux is this _massive_ thing
   now, and NetBSD has not been able to keep pace with all of
   the features, although it's kept current on the features it
   _did_ have and has added architectures. The source code is
   readable and once again I feel like I can (kind of)
   understand the system that I'm working on.

   Getting a second UART working means that I can run PPP over
   one of the serial channels (to /dev/ttyAMA0 on a Pi400
   running Linux) and still have a serial console and access
   the kernel debugger on the other serial port.

   All of this is working towards a medium-term project for me:
   add a driver to the NetBSD kernel. Specifically, a driver
   for the ENC28J60 SPI-attached Ethernet controller.

   (I expect many crashes, which is why access to the debugger
   is neccessary)

   I don't really need this, but working through the datasheets
   of a small system and writing C (and learning about DTB) has
   been a really pleasant experience. Not sure why; I don't
   want to overanalyse.

   Anyway this is closer to a blog post than a .project update
   so bye!