exxos's Atari, Amiga & retro forum

Thank you for testing.

I think I am done with this project. I can't think of any more features that need to be implemented.
It generally does what it was planned for and much more.

I have completed work on Rev2.1 PCB, which has few additional parts to improve sound quality (decoupling caps, low pass filter, stuff like this.). Plus I removed LEDs, button, crystal spot and crystal caps.
I will order it next week.

I made firmware compatible with all chips from this form factor and type, improved sound for Rev1 by enabling built-in buffer on DAC.
I should update docs and BOM one day.

I have 4 spare built Rev2 carts if someone is interested.

There is new firmware 2.1.7

It contains MSX reset fix. Cart could only reset to game after reset button was pressed, you couldn't start flashing pages.

I have added some fixes to ASCII16 mapper.

There was a report that this cart works only with slot extender on Omega MSX, so unfortunately it is not compatible with this MSX.

I have ordered Rev2.1 PCB. It has only few additional changes in SCC circuit designed to reduce noise.

arkadiusz.makarenko wrote: 03 Apr 2025 21:12 I have ordered Rev2.1 PCB. It has only few additional changes in SCC circuit designed to reduce noise.

What did you have to change?

PhilC wrote: 03 Apr 2025 21:26

arkadiusz.makarenko wrote: 03 Apr 2025 21:12 I have ordered Rev2.1 PCB. It has only few additional changes in SCC circuit designed to reduce noise.

What did you have to change?

I have added decoupling caps and low pass filter, I have made sound lines a little bit wider as well. I am not sure how effective it is before I try it.

@arkadiusz.makarenko all sounds good to me and should improve sound quality.

I have released new PCB 2.1 and new firmware 2.1.8

At last I managed to sync PCB and firmware versioning.

arkadiusz.makarenko wrote: 21 Apr 2025 15:03 I have released new PCB 2.1 and new firmware 2.1.8

At last I managed to sync PCB and firmware versioning.

:cheer: :cheer: :cheer:

PhilC wrote: 21 Apr 2025 15:41

arkadiusz.makarenko wrote: 21 Apr 2025 15:03 I have released new PCB 2.1 and new firmware 2.1.8

At last I managed to sync PCB and firmware versioning.

:cheer: :cheer: :cheer:

There is no substantial noise reduction on new PCB, but it is a little bit better, but not really worth of upgrading from Rev2 to 2.1
I checked it on two different pin compatible op-amps.
MCP-6001T is dealing with noise much better than TL071.
I have impression that sound from TL071 is a little bit crispier,but noiser, it may be because different volume levels as well.

I think this noise is from the chip DAC itself, so there is not much I can do about it.

@arkadiusz.makarenko the version 2 sounds good to me, so any improvement is great.