TF536 Rev 2 Design Complete (all gone)

[LADmachining]

No change with a different CPU, or on a completely different A500 board (rev 6a, also running KS3.1).

Going to reflow the CPLD again to see what effect that has.

What value resistor networks did other use for the missing ones on the underside? I used 2K2.

[8 Bit Dreams]

Spent some time with TF536 rev.2 today,
Got very good results, card works just nice even with cheap SAMSUNG K4S561632-UC75 ram installed (according to datasheet this ram works @110Mhz, seems we are within the specs with 100Mhz) tried to run different demos, Frontier and Nemac, no problems noticed, now waiting on FedEx to try out buffered ide

20200426_214444.jpg

[dalek]

Spent some time with TF536 rev.2 today,
Got very good results...
....

Nice! What are your CPLD temps like? warm? not warm?

[alenppc]

Spent some time with TF536 rev.2 today,
Got very good results, card works just nice even with cheap SAMSUNG K4S561632-UC75 ram

Where did you buy this RAM? UTSource? It doesn't seem available on either Digikey or Mouser.

Btw, I confirm that the Xilinx chips I got from UTSource are ok.

[8 Bit Dreams]

Ok guys,
got buffers on TF536 and removed RN6 - RN10.. What can i say..It isn't working, card starts with flashy bars, but then power LED starts to pulse with reboot followed..
Will swap ram chips later to see if i get further..

[PaulJ_2.0]

Ok guys,
got buffers on TF536 and removed RN6 - RN10... What can i say... It isn't working, card starts with flashy bars, but then power LED starts to pulse with reboot followed..

Yeah it doesn't work for me either, I would like it to, so I might look into it a little deeper to try and see what might be the issue.

[8 Bit Dreams]

oh,
ok, good to know, so i can save this step with swapping ram.. :geek:

[terriblefire]

Ok guys,
got buffers on TF536 and removed RN6 - RN10... What can i say... It isn't working, card starts with flashy bars, but then power LED starts to pulse with reboot followed..

Yeah it doesn't work for me either, I would like it to, so I might look into it a little deeper to try and see what might be the issue.

Try just buffering the data bus pins.. .if that doesnt work just buffer the control lines. etc.. (control lines are the buffer chip inside the 68000 socket).

[8 Bit Dreams]

Ok, removed chip for control lines and placed back RNs - got boot now :thanksyellow:
plain ide speed is a little bit slow (880kb/s), muFastrom does it much more comfortable to use: 4,3MB/s wich is more than enough for most of existing tasks. im very pleased, Thank You Stephen!

Next step is to add 30cm cable and see how stable will it be, but im already loving it!

SIDENOTE!
have noticed one detail while removed RNs: some pins wasn't tinned at all, seems they are using low quality soldering paste, have resoldered all RNs now..

[terriblefire]

Here is the control buffer logic schematic..

I think its possible you need to lift IOR/DIR pin on the control buffer and tie it high or low to make it work.. must have overlooked this.

buffer.JPG

EDIT: Pin 1 on this chip needs lifted and tied high to make the buffer work. Will fix it on the next batch (2b) if someone confirms it working. Should be possible to lift the pin and tie it to pin 2 which is also high.