CURRENT PROTOTYPE STATUS (SEC 64MHz 68000)

Information and news about the 68SEC000 64MHz booster.
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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)

Post by exxos » Tue Nov 20, 2018 2:07 pm

Got some tidying to do, but "layer 3" the connection from the SRAM/ROM data/address bus is routed now..

Need to find some easy PLD IO pins next to route to the SRAM CE lines..

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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)

Post by PhilC » Sun Nov 25, 2018 1:27 am

Hi Exxos,

Quick question, will the on board ram of the STFM or Mega need to be disabled to use this board? Or will it just add an extra 8mb of fast ram?

My STFM is only 512k and didn't want to spend lots of time upgrading it if the Ram is ultimately not going to be used. (It's a spare machine that I've been fixing, waiting patiently for the SEC booster to be bought to life.)
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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)

Post by exxos » Sun Nov 25, 2018 2:07 am

Fast ram has nothing to do with st ram. So you can have the normal 4mb st ram plus 8mb fast ram.
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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)

Post by PhilC » Sun Nov 25, 2018 11:00 am

exxos wrote:
Sun Nov 25, 2018 2:07 am
Fast ram has nothing to do with st ram. So you can have the normal 4mb st ram plus 8mb fast ram.
Ok that's what I thought. I'd better decide how I'm upgrading it to 4mb then.
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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)

Post by PaulJ » Sun Nov 25, 2018 2:29 pm

Have my mega 4 setting here just waiting for it. Just pop the 1.5 out and were ready. :excited: :excited: :excited:

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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)

Post by exxos » Sun Nov 25, 2018 2:45 pm

I will try and find some time this week to build up one for testing.. i need to finish up the STE boosters as can only work on one machine at a time :)

The firmware *should* be compatible with the previous V2.2 booster...
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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)

Post by exxos » Thu Jan 03, 2019 9:39 pm

I've plugged in my SEC booster to help TF with his floppy write problem, which I seem to have as well :roll:

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Long story short, seems there needs to be a delay on CPU_DTACK after a DMA cycle. So I run ST_BGACK though a FF clocked on 8MHz to buffer/delay the signal and add it to my CPU_DTACK delay logic. So normal RAM access works same speed as before, but CPU is stalled with DTACK a extra 8MHz cycle after a DMA cycle..



The problem is, I get this at the start of each format..

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Formatting a floppy works fine now though (was just resetting after a couple of track formats). Not really sure if that error is a booster error or a "bug" in TOS due to the faster (50MHz) CPU ?

I will add on the pull ups onto the DMA just to see if that has anything to do with it also...
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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)

Post by exxos » Thu Jan 03, 2019 10:11 pm

So the pull up fixes on the DMA & 1772 didn't help..

But when the drive motor is off, and I click OK to format, I get that error.. if I wait for the motor to turn off, I can repeat the error every time.. if I click retry while the motor is on, it works fine.

Even more odd, it works fine with a original 720K drive.. hmm..... :stars:

Oddly the format fails towards the end with my 720K drive (bad floppy probably) and I get that error and can't get any further by clicking RETRY.. I guess because the motor is now off.. very odd....

EDIT:
The 720K failing format and the error happens with the stock 68000, so must be a TOS issue...
The diagnostic cart reports no floppy issues..

I will try FCOPYIII....Seems to work ok as well..
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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)

Post by troed » Fri Jan 04, 2019 8:39 am

Don't know if it's related but on the doubleST I've had, several times, that "everything" seemed to work ok except floppy. So far it's been fixed by "luck" just shifting the clocks about a bit - which if I've understood your comments before mostly means I've skewed DTACK.

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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)

Post by exxos » Fri Jan 04, 2019 11:14 am

troed wrote:
Fri Jan 04, 2019 8:39 am
Don't know if it's related but on the doubleST I've had, several times, that "everything" seemed to work ok except floppy. So far it's been fixed by "luck" just shifting the clocks about a bit - which if I've understood your comments before mostly means I've skewed DTACK.
I never thought about it with the floppy acting up... Can you format a floppy OK on it now then or does that act up still?

For me its odd, but seems more like a TOS problem as only gem format seems to be malfunctioning..
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