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Of course the thread title could have also been called "the PS2 portable of Theseus" because that's kind of how it came about.
I've continued to try and perfect the PS2 portable I made for the BitBuilt competition back in 2020 (man doesn't that feel like a lifetime ago!) and I think I'm at the stage where I'm looking at getting a new carrier board made for it, hence I'm considering it to be a "new" portable (this also means I have, and have not, gone back against my oath to put down the iron and focus on other life stuff? I'm unsure here).
What's of immediate note is the project that MomSpagetti and I have been working on: to hard-wire the PS2 ethernet phy to phy using the smallest mobile router we could find, the GL-MT300N-V2 "Mango". Now while GMan's Pi3 inclusion in the PS2 Razer is a monumental step for modding, the method of capacitive coupling hasn't been replicable with different devices hosting different chipsets, and in the past people have used transformers scavenged from special RJ45 ports.
We needed a better way, and this is where someone could probably write a guide as I'm sure it'd be useful:
After weeks of pouring over documents the solution for this turned out to be contained in a document from Micrel (https://www.eeweb.com/wp-content/up...-coupling-ethernet-transciever-1321248893.pdf). Something the article was light on is that the ethernet bias for both sides needed to be correct, so for the PS2 this was 1.75v, and the Mango used the RX0 line instead of the 3.3v (not sure why). This has to do with the setup of the Broadcom (PS2) and Mediatek (Mango) chips and the expected bias. Simply put: if these aren't correct you'll frustratingly get listings, but nothing will load.
Now it's worth noting that I had the occasional stutter with my "antenna test setup" but I'm confident that this interference will be mitigated by shortening the leads. While this is fresh in my mind I'll also note that this setup probably won't be applicable for all systems as some chips apparently necessitate the use of magnetics or more elaborate phy interface circuits, but this is something that can be easily compressed into a small space.
Pertaining to variance in bias voltages: The numbers are pretty inflexible. I tested the PS2 with 1.25v, 2.5v, and 3.5v as provided by the PS2 board, and found that I was able to get listings but no games would load. I suspect that there's a slight tolerance to the ratings of capacitors and resistors here as I wasn't technically using the correct ratings, but couldn't say how durable the method is for large amounts of variance. Technically this is a double-biased system with both the PS2 and Mango having different bias voltages, so there should be a 100nF capacitor attached to the VDD lines as per the documentation from Micrel, but I'd assume that both systems had necessary smoothing in my tests.
That task done I'm going to promptly forget all of this and move on with lifes next task!
I've continued to try and perfect the PS2 portable I made for the BitBuilt competition back in 2020 (man doesn't that feel like a lifetime ago!) and I think I'm at the stage where I'm looking at getting a new carrier board made for it, hence I'm considering it to be a "new" portable (this also means I have, and have not, gone back against my oath to put down the iron and focus on other life stuff? I'm unsure here).
What's of immediate note is the project that MomSpagetti and I have been working on: to hard-wire the PS2 ethernet phy to phy using the smallest mobile router we could find, the GL-MT300N-V2 "Mango". Now while GMan's Pi3 inclusion in the PS2 Razer is a monumental step for modding, the method of capacitive coupling hasn't been replicable with different devices hosting different chipsets, and in the past people have used transformers scavenged from special RJ45 ports.
We needed a better way, and this is where someone could probably write a guide as I'm sure it'd be useful:
After weeks of pouring over documents the solution for this turned out to be contained in a document from Micrel (https://www.eeweb.com/wp-content/up...-coupling-ethernet-transciever-1321248893.pdf). Something the article was light on is that the ethernet bias for both sides needed to be correct, so for the PS2 this was 1.75v, and the Mango used the RX0 line instead of the 3.3v (not sure why). This has to do with the setup of the Broadcom (PS2) and Mediatek (Mango) chips and the expected bias. Simply put: if these aren't correct you'll frustratingly get listings, but nothing will load.
Snippet of document schematic that was followed:
As a schematic from KiCad:
Also worth noting is the wiring of the ports for the Mango: The ethernet is mounted upside down. This diagram is from the underside of both units (we need more MSPaint around here!):
As a schematic from KiCad:
Also worth noting is the wiring of the ports for the Mango: The ethernet is mounted upside down. This diagram is from the underside of both units (we need more MSPaint around here!):
Now it's worth noting that I had the occasional stutter with my "antenna test setup" but I'm confident that this interference will be mitigated by shortening the leads. While this is fresh in my mind I'll also note that this setup probably won't be applicable for all systems as some chips apparently necessitate the use of magnetics or more elaborate phy interface circuits, but this is something that can be easily compressed into a small space.
Pertaining to variance in bias voltages: The numbers are pretty inflexible. I tested the PS2 with 1.25v, 2.5v, and 3.5v as provided by the PS2 board, and found that I was able to get listings but no games would load. I suspect that there's a slight tolerance to the ratings of capacitors and resistors here as I wasn't technically using the correct ratings, but couldn't say how durable the method is for large amounts of variance. Technically this is a double-biased system with both the PS2 and Mango having different bias voltages, so there should be a 100nF capacitor attached to the VDD lines as per the documentation from Micrel, but I'd assume that both systems had necessary smoothing in my tests.
In theory if I can get it working like this then it'll work great when everything is shortened down!
That task done I'm going to promptly forget all of this and move on with lifes next task!
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