RISKY MSX Rev2

[arkadiusz.makarenko]

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.

[arkadiusz.makarenko]

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.

[arkadiusz.makarenko]

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

[PhilC]

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?

[arkadiusz.makarenko]

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.

[PhilC]

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

[arkadiusz.makarenko]

I have released new PCB 2.1 and new firmware 2.1.8

At last I managed to sync PCB and firmware versioning.

[PhilC]

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]

I have released new PCB 2.1 and new firmware 2.1.8

At last I managed to sync PCB and firmware versioning.

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.

[PhilC]

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