TF CD32 Riser Revision 2 Design Complete

[terriblefire]

Is there space for buffering the H and V Sync signals like the Active 23wD to VGA adaptor has?
Have one of those adaptors but it puts a fair bit of weight on the Riser, with the adaptor and a chunky VGA cable it moves the top away from the CD32
making it a bit flakey in operation.

There is a reasonable amount of room here. its choosing the right chip. One that will not end up EOL next week is what is concerning me,.

[juz400]

I built one in the 90`s for a mate so he could use an NEC mutlisync on his A4000, IIRC we need a schmitt trigger inverter?

These are brand spanky new from On-Semi, pretty cheap too or should I look for a Dual model?
https://www.mouser.co.uk/ProductDetail/ ... 52B7cs0%3D

[terriblefire]

I built one in the 90`s for a mate so he could use an NEC mutlisync on his A4000, IIRC we need a schmitt trigger inverter?

These are brand spanky new from On-Semi, pretty cheap too or should I look for a Dual model?
https://www.mouser.co.uk/ProductDetail/ ... 52B7cs0%3D

You dont want to invert the signal if you simply want to use the D23 as many of us do.

[terriblefire]

@arkadiusz.makarenko I have pushed all the changes to the branch. It includes a video buffer chip. Just needs checked over and we're good.

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EDIT: What did you change the HSE XTal for ?

[arkadiusz.makarenko]

@arkadiusz.makarenko I have pushed all the changes to the branch. It includes a video buffer chip. Just needs checked over and we're good.

Capture.PNG

EDIT: What did you change the HSE XTal for ?

The same type, but 25Mhz.
This allows me to set up all clocks, including 48Mhz for USB. I am not sure if it will be 100% stable, as my stm32 Nucleo board was a little temperamental running 216Mhz saying that this board is very solid.

I had a look and initially I was a little bit worried about dropping number INTSIG, but then I realised that SPI lines can be used if those will not be in use.

LSI crystal footprint was little bit unusual as I always seen them in different cylindrical package ... I guess I spend too much time with cheap Chinese knockoffs

[terriblefire]

The same type, but 25Mhz.
This allows me to set up all clocks, including 48Mhz for USB. I am not sure if it will be 100% stable, as my stm32 Nucleo board was a little temperamental running 216Mhz saying that this board is very solid.

OK i'll use 25Mhz for the build.

I had a look and initially I was a little bit worried about dropping number INTSIG, but then I realised that SPI lines can be used if those will not be in use.

I've not removed any INTSIG lines.. instead i removed TXD/RXD from the ARM (that is the direct connection to the CD32 internal UART) and moved R/W, INTSIG8 and KB_DATA. DSACK0 has been dropped and A5 added. So things have moved but have not been lost.

LSI crystal footprint was little bit unusual as I always seen them in different cylindrical package ... I guess I spend too much time with cheap Chinese knockoffs

That may change but its the same package as the other one.

I think i'll order 5 assembled if you think this will work.

EDIT: updated the 32.Khz crystal footprint too.

[terriblefire]

5 ordered..

Screenshot 2020-10-14 at 23.01.43.png (826.55 KiB) Viewed 2889 times

[arkadiusz.makarenko]

5 ordered..

Screenshot 2020-10-14 at 23.01.43.png

Wow, This went quickly!

[kulamario]

Can I buy one for my self if is possible ?

[terriblefire]

Can I buy one for my self if is possible ?

If it works you can get one of the 5 from me. I may send an extra to Arek and ask him to assemble for me as currently I have no solder station.