WIP: DC-DTE using netbsd

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TechFragments
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WIP: DC-DTE using netbsd

Post#1 » Fri Mar 31, 2023 11:27 am

Preparation Step. Assemble a breakout board for added functionality with the proposed system.
DC breakout bottom.jpg

DC breakout top.jpg


Step 1. Flash a new fast-boot bios to load the kernel (dreamboot-nogdrom), as I am using a G1-ATA adapter.

Step 2. After flashing and verifying, remove the stock bios as it sereves no purpose for this project.
Notice, a trace lifted while removing the stock bios, so I added a bodge.
DC mod phase 2.jpg


Step 3. prep the ram chips with flux; you can never use too much
howmuchfluxisenough.jpg


Step 4. Dope the existing solder with leaded solder while forming a heat sinking bar
somanybridges.jpg


Step 5. use a heat gun with a fine tip nozzle and low air flow to remove the packages, then clean the ram pads with solder wick, and more flux
cleanboard.jpg


Step 6. prepare the necessary ram pin bridges for one-time installation, then attach the chips.
On a side note, the tech. documentation states that the WriteEnable pin must be pulled to VCC for the rom to be readable; I struggled with that fact
postinstall.jpg


nearly there...
newhope.jpg


Building the OS
as the definitive guide refer to netbsd-howto for a broad explanation.

First download the netbsd-10 resources from the FTP-repo, in the tar_files folder; the xsrc is only needed if you plan to use a gui, src.tar.gz for most other applications.

Then to make life simpler, find a spare flash-drive and use the Rufus tool to install a live linux iso to the drive, specifically DebianDog, as it supports creating archived changes to the live ISO. Grab the 64-bit version of the jessie distro here DebianDog64-Jessie-openbox-2016-03-20.iso

After installing the ISO to a drive, use your imagination to resize the partition for some work-space on the rest of the drive, or work within the folders of the distro, but that's a little cumbersome.

Grab an archive that I have prepared so that netbsd can be compiled without messing with dependencies, unix, etc. here: build-dependencies

After booting the live ISO use the included distro tools to mount the build depency archive

Now that all the files are collected, arrange the source tree so that it looks something like this
folder-tree.jpg


Open a terminal and cd to the src folder, then set a couple of environment variables so the build chain doesn't get confused.
export HOST_CFLAGS="-std=gnu11"
export MAKE="make"

After issuing the next command the netbsd tools should build, granted you may need to change the folder tree a little. The distribution always runs in root, so theres no need for a -U parameter to the command.
./build.sh -O ../obj -T ../toolchain -D ../dest -R ../release -j2 -m dreamcast tools

If everything goes well you will see a screen like this
tools-build.jpg


I just migrated all the old patches (SCIF-MMC & G2-ATA) and have uploaded the source folder if you would like to build the latest kernel. The dreamcast specific files from /src/sys/arc are here: sources.zip

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