exxos's Atari, Amiga & retro forum

PhilC wrote: 10 Feb 2025 21:19 @arkadiusz.makarenko always worth checking the soldering

Soldering is fine.... (unfortunately)

I took a programmer and removed read protect and set up memory assignment (which I have internal routine to set it up as well) and set up again 288KB flash + 32KB RAM. and it works now!

Issue is that I have internal piece of code to do it at power up, and during programming it should be set up at this value as well.


Edit:
...5 minutes later stopped working again ... AA!!

I honestly believe I am hitting performance celling of this chip, and some MSXs are a little bit more tolerant than other.
I can't do much more in code. It is optimized to almost maximum now.

I have two options, look for faster chip and port code.
Alternatively I can add a crystal oscillator and experiment with overclocking by like 10-15%. I was about to order new PCBs anyway, so I can include external crystal setup (conveniently I have space on PCB exactly where oscillator should go).

I have came up with few improvements.
I managed to play Nemesis 3 with SCC stable to like 10 minutes (on hardware that refused to cooperate yesterday)

There is some stuff that has to happen during the cycle, like reseting interrupt flag. I was doing it at the begging, but I moved it to slot when cart is waiting for end of the cycle.

Second move was when I do checks and basic calculations waiting for start of write cycle. Like reading data from the bus.
I maybe will move other staff there as well like calculating next position for circular buffer etc.

Hopefully this will work for most MSXs.

I tried 0.7.3 and unfortunately it seems to break Nemesis 3 on my HX-10.
After you select weapons and the main action screen starts the action part of the screen has loads of horizontal lines. The UI part of the screen is ok though.
Will be interesting to see what @PhilC gets

Higgy wrote: 11 Feb 2025 21:53 I tried 0.7.3 and unfortunately it seems to break Nemesis 3 on my HX-10.
After you select weapons and the main action screen starts the action part of the screen has loads of horizontal lines. The UI part of the screen is ok though.
Will be interesting to see what @PhilC gets

Sorry,
I haven't released this version with workarounds yet. I need to retest all mappers first.

It will be marked as v0.8

And I have released v0.8 now.
I really hope it will make a difference, at least on HX-10s

I have adjusted HSI clock to max - "micro overclocking"

I have reviewed data types on circular buffer to make sure they work as efficiently as possible.
I have moved some processing to sections in bus cycle when we should be waiting for something

I have added one more optimisation on v0.8.3 - I moved some constant values to literal pool. This should shave off another few cycles. Plus fix pointer
...plus cold boot fix for KONAMI SCC mapper

I'll hopefully be able to give it a go shortly

0.8.3 seems to be working well for me. 8-) Also got Knightmare (SSC) working, which I had not got running on previous Firmware.

Tried about 10 various games and got them running apart from a 'Tape to ROM', which I've not investigated beyond trying 2 different mappers.

Higgy wrote: 12 Feb 2025 18:08 0.8.3 seems to be working well for me. 8-) Also got Knightmare (SSC) working, which I had not got running on previous Firmware.

Tried about 10 various games and got them running apart from a 'Tape to ROM', which I've not investigated beyond trying 2 different mappers.

Great news!

I hope we will be able to replicate this on other MSXs.