PSNee further development

[Pandor]

tried the suggested delays, but still no bios patching going on.
ohwell, atleast CDR is working, and this is a fun way of getting into AVR's.

Plus while testing I found that all the sony branded Taiyo yuden CDR backups (dating from '99 -'00) still boot just fine (even better then some of the originals). unlike all the other brands (TDK, JVC, Pioneer, Intenso... all as good as dead).

[rama3]

Maybe the part just isn't precise enough for this kind of speed.
The internal oscillator can be calibrated using some Arduino sketch. That might help.

[Pandor]

Frietman did implement bios patching on the attiny (in psnee v6).
Although it seems like a crude implementation, from what I read, it was functional...
maybe these (timings) should be reverted for the attiny implementation.. From a first glance at the code, he used less delays overall...

I came across some of his logic analyser logs, and discussions, so I might go over them and see If I can experiment a bit. Unless someone with more knowledge and tools would care to step in....

It would be nice to have a all-in-one attiny drop-in replacement for those old pic based mods, especially with how psnee v7 implements subcode routines. This is really a nice stealth solution.

on a sidenote.: according to the specs, PB5 (RESET) can be used as a "weak" I/O, but D2 only needs to be pulled low @ a certain time, so i did make sure D2 is on pin1, as a precaution. But A18 is only used for input/timing, so I guess it doens't really matter.

[rama3]

The Attiny is without Arduino bootloader and startup speed is set to fast, right?
I ask because the first event happens very shortly after power up.

You can try the old timings. Maybe they work better.
The code for the patch is super simple. It's just the timings that are important.

[Pandor]

These are blank attiny's I bought, and i'm programming the exported hex with a tl866 programmer (supports hvspi), so there is no bootloader involved and the fuses are: LFUSE 0xE2 HFUSE 0x5F, so boot should be fine...

[rama3]

You obviously spent some time on this now. Why not get rid of all the modchip action and reduce the code to just the BIOS patch. Then you can change pins easily and maybe even have ICSP, so the chip can stay installed when you debug.
I tried looking for my Attiny45 the other day, but couldn't find it :/

[kchung]

I'm trying to write my own modchip in micropython based on PSNee but can anyone explain what is different about the PU-22 that requires special code?

Using a logic analyzer it looks like my code is working properly but since I only have PSOnes and a PS1-7501 I assume my code doesn't work b/c it is too simple. It's based off of the V1 of PSNee.

> The other thing is that the gate/data approach doesn't work very well with the later (PU-22 and on) consoles, because they no longer have the external connection to the mechacon for the SCEx data - connecting the data to the tracking error amplifier input on the CD/SPU chip sort of works, but it also degrades the performance of the tracking servo because when the chip driving low there is no tracking signal.

I saw this comment on AssemblerGames but I'm not familiar enough with the PS1 yet to understand the implications.

EDIT: I got my Python based modchip to work reading more of the PsNee v6 code from Frietman. I'll release it soon but for some reason Spyro Year of the Dragon detects the modchip despite it not injecting. Perhaps my code is wrong or I'm missing something.

[Pandor]

You obviously spent some time on this now. Why not get rid of all the modchip action and reduce the code to just the BIOS patch. Then you can change pins easily and maybe even have ICSP, so the chip can stay installed when you debug.
I tried looking for my Attiny45 the other day, but couldn't find it :/

Sorry for the late reply. life caught up with me and was short on free time.
As i said before, i'm not a dev, so i'm learning as I go reading code, looking stuff up, so not really a fluent coding experience. But still a nice project to get into AVR.

I've been looking up 'direct' port manipulation, and that seems to really speed things up, so i might look into converting most of the the code, and see if that would make it more stable/workable on a standalone attiny. and take up on your tip, and just see if I can get patching working, and go from there.

But this is getting to be a lengthy process

[ultrasuede]

Hi, does anyone have a diagram of the PU-22 PAL version?

[x7502x]

Check my post a few pages back for the pu-22 diagram, its for the micro but the ps points are the same. also reading back through the thread it states to have no boot loader or power on before is this certain models?? as the pu22 and pm41 I have both pals boot fine using a boot loader powered by the play station, I'm using a 5v pro micro.

[rama3]

The no bootloader requirement is only for PAL PSOne (white slim) models with the BIOS patch active.

[Pandor]

Check my post a few pages back for the pu-22 diagram, its for the micro but the ps points are the same. also reading back through the thread it states to have no boot loader or power on before is this certain models?? as the pu22 and pm41 I have both pals boot fine using a boot loader powered by the play station, I'm using a 5v pro micro.

Running the 5v pro micro 16Mhz on 3.3v?
How's that working out? This always confused me in the readme. These atmel chips are not meant to be run on 3.3v 16mhz.
Yet, the mod is meant to run on 3.3v.

So is the codes optimised for 16mhz, or 8mhz?
I'm still looking into getting it to run reliably on a attiny. Next up is a attiny48. Enough pins for serial output and a crystal for comparing and testing.

[rama3]

The chip is undervolted at 3.3V.
I tested some chips and Pro Micro boards and they all worked fine at even lower voltage.
So, it's not within specs but it will work anyway.

[modrobert]

Running the 5v pro micro 16Mhz on 3.3v?
How's that working out? This always confused me in the readme. These atmel chips are not meant to be run on 3.3v 16mhz.
Yet, the mod is meant to run on 3.3v.

So is the codes optimised for 16mhz, or 8mhz?
I'm still looking into getting it to run reliably on a attiny. Next up is a attiny48. Enough pins for serial output and a crystal for comparing and testing.

The Pro Micro board has a voltage regulator which can handle 2.5V - 12V input range, same goes for the Arduino Pro Mini board, voltage will always be correct for the MCU as long as you use the RAW pin (not VCC).

[rama3]

modrobert:
The voltage regulator can only convert a higher input voltage to 5V on these boards.
The reason we connect these boards to 3.3V unregulated is that the output will then not require level translation.

So in short: Keep using 3.3V from the PSX directly. This is how I designed it.

[x7502x]

I'm sure i enabled the bios patch on the pm41 pal and it worked, the psone is now a android box with a laptop fan as they run at 70+c, now between 35-45c, my 750x has not been on for a while but when I was playing with psnee on a micro at 3.3v not one single failed boot it worked flawless, although I don't see much benefit to using the micro but the the ported version is a few pages back if you want to try it.

[modrobert]

modrobert:
The voltage regulator can only convert a higher input voltage to 5V on these boards.
The reason we connect these boards to 3.3V unregulated is that the output will then not require level translation.

So in short: Keep using 3.3V from the PSX directly. This is how I designed it.

Ah, OK, totally forgot about the output pin voltage levels from MCU, yes, that would be bad.

So, I assume the recommendation is to use VCC as input pin for these boards?

(Unless the board is 3.3V, then RAW pin should be OK.)

[rama3]

A voltage regulator always requires a little more input voltage than what it should output.
Even optimized "LDO" or "low dropout" regulators still require something like 4V input for a stable 3.3V output.

My recommendation is to always use the PSX 3.3V to power the MCU directly, bypassing any regulator.
The worst that can happen this way is that the chip doesn't work / unlock the Mechacon.
But yeah, I've had these at below 2.7V and still work reliably. There is a big margin, maybe also because I don't use any big power stuff.

[pedrajasilva]

Hi. Im new in this. I just want modchip my ps1 (pu-22 ntsc u/c motherboard) but im very confused with this. I need only write the code on my arduino pro mini and this is all? Sorry if english is bad. Im a spanish native. Can someone help me? Thanks in advance

[EmteCoke]

Hi, Just wondering if anyone installed the PSNee on a SCPH-1000 PU-7 motherboard.. I have the MM3 modchip installed but would like to replace it with the PSNee.. I just can't find installation pix on how to install it... Is it the same pin out as the MM3 installed on the SCPH-1000??/ Thank in advance!!!