CURRENT PROTOTYPE STATUS (SEC 64MHz 68000)

[exxos]

@PhilC Once you done this https://www.exxosforum.co.uk/forum/viewt ... 893#p31893 and you get your SEC booster running (ask @Icky for images how to fit it to the H4 ) See if ultrasatan and the floppy drive behave. Icky can't get ultrasatan working correctly with the SEC installed. Though its all currently working fine on my STFM here.

[PhilC]

@exxos will do. Will start with a good STFM and once that works, move on to the H4.

[Icky]

After discussing with @exxos it seemed to be the Blitter causing the issue. After removing Blitter the floppy and UltraSATAN works together. However am still having issues with Gigafile.

@PhilC - just go straight for the H4. It’s a very easy install.

[PhilC]

After discussing with @exxos it seemed to be the Blitter causing the issue. After removing Blitter the floppy and UltraSATAN works together. However am still having issues with Gigafile.

@PhilC - just go straight for the H4. It’s a very easy install.

Will do @Icky

[exxos]

It be interesting what speed you get with tos206 with glitter as I've still got slower than expected speeds on my stfm. I get 175% first test but the ste is 181% but as ROM is faster on the sec the speeds should be more like 190%.

[exxos]

Been doing a lot of tweaks. Getting TOS104, TOS206, BLITTER, ULTRASATAN all to play nice is a nightmare.

Mostly , for some odd reason, TOS104 I need to wait for ST_DTACK to go high before allowing any ROM decoding to happen. TOS206 doesn't seem to care.. Without that sync delay, TOS104 resets when accessing C: drive, TOS206 doesn't. ROM speed has dropped a bit, but still at 309%. First GB6 test has dropped from 172% to 163%... will fiddle more tomorrow.

[exxos]

This isn't a very exciting test.. But I kept reducing the DTACK pull up (about 434R now!) To see what would happen, and the figures have gone up ever so slightly..

dt.jpg (153.27 KiB) Viewed 3139 times

I think what the problem is in terms of ROM speed access, is that because ST_DTACK is so slow, I have to wait for it to go high before I let the CPU read DTACK as issued by the PLD logic. Otherwise the CPU reads the end of the ST_DTACK cycle and completes ROM access a lot sooner, normally before ROM is even ready.


A edit to the ROM code and we jump to 345%. I think thats as good as its ever going to get.

dt2.jpg (72.72 KiB) Viewed 3137 times

I removed my DTACK resistors and got 164% first test, and it crashed on the second test Either way DTACK will likely need a lower value to gain the extra speed.

Next to try about 600R on ST_DTACK.. First GB6 test 163% and ROM speed is 309% again. So seems 400R is needed , thats a little low really.


more to come later...

[PhilC]

My board arrived today, hope to test it out tomorrow.

[Icky]

My board arrived today, hope to test it out tomorrow.

Great @PhilC. I just posted a guide on how to install here - https://www.exxosforum.co.uk/forum/viewt ... =78&t=2466

You can replace the ROM on the H4 with the 104/206 one you have on your IDE DEV board to take advantage of TOS 206.

Will be interesting to see how yours behaves compared to mine on the H4.

[PhilC]

@Icky yes thanks for posting that. I'll have a go a bit later on. Hopefully fix the SMT board too whilst I'm at it.