Icky - Progress

[Icky]

Icky,

I got the cables from Best Electronic who as I understand it purchased most of Atari's stock when they went belly up. They have a lot of the hard to get parts and they also make new replacement parts. I'm not very good at waiting and they ship quick. I usually get what I order in two or three days. They have a catalog you have to buy hat shows everything that was available for all the Atari products all though a lot of the items they don't have any longer. The bad part is they are only open 1:30 - 5:00 pm pst. I aways call, I guess you can order via email.

http://www.best-electronics-ca.com

That’s a good shout to help diagnose. Where did you get those from?

There is a second source: http://gossuin.be/index.php/shop, search for "ATARI LOOP HARDWARE TEST for Test Kit Cartridge".

Thanks both.

[PaulJ]

Yes, I've dealt with Gossuim, purchased a couple of mega 4's without a keyboard and used his adaptor to use ps2 keyboard and mouse. I guess it has a number of additional functions to. Very happy with his products but shipping was expensive and so slow. Best has a lot of stuff and one characteristic I really like. Fast shipping. .

So Icky.. have you got the DMA port running yet?

[Icky]

Yes, I've dealt with Gossuim, purchased a couple of mega 4's without a keyboard and used his adaptor to use ps2 keyboard and mouse. I guess it has a number of additional functions to. Very happy with his products but shipping was expensive and so slow. Best has a lot of stuff and one characteristic I really like. Fast shipping. .

So Icky.. have you got the DMA port running yet?

No DMA yet. I have fixed my faux pas from yesterday. Have been working through Exxos' suggestions but am slow going tonight.

[exxos]

No DMA yet. I have fixed my faux pas from yesterday. Have been working through Exxos' suggestions but am slow going tonight.

Annoying that no sign of my board still

The DMA should be in a "ideal circuit" on this STF board.. if all signals are clean, then mission done in that respect, good grounding, so DMA should be working perfectly as it doesn't suffer from all the problems like the STFM and STE had

Might be worth checking the MMU pins such as DEV(pin31) , /RAM(pin 33), /DMA(pin 24) and make sure nothing nasty on those lines..

Though really if floppy is working fine.. so should the hard drive...

[exxos]

One thing which bugs me a tiny bit, is no pull up on ACK on the DMA port (and some other pins) ... But I would check each pin on the DMA port and make sure you got a good 5V/0V levels there just to be sure... and you will have to be trying to access the drive to see the signals switch...

[Icky]

One thing which bugs me a tiny bit, is no pull up on ACK on the DMA port (and some other pins) ... But I would check each pin on the DMA port and make sure you got a good 5V/0V levels there just to be sure... and you will have to be trying to access the drive to see the signals switch...

Problem I have is I cant load the HDD drivers to access the drive (i.e. to see the signals as you mention) as the floppy does not get recognised when plugging in the HDD.

[rpineau]

So you get to the desktop at some point but with no drive showing (FDD and HDD) ?
It would seem that plugin the HDD affect one or more of the signal common to the HDD port and floppy :
CD0 to CD7
CA1
R/W

... OR ... one of the signals from the DMA port (HDD) to the DMA (chip) is in a state that blocks the DMA from talking to the 1772.
DRQ , ACK

And there is the /FDINT from the DMA port that gets combined with the 1772 /INTR via U51B and U32B and goes to the MFP I5
These are pretty much all the signals.
You could try to bend the DRQ and ACK pin out of the socket (gently bend them so that when the DMA is in the socket they are out of the socket) and see of this still blocks the floppy.
You might also want to bend the HDCS (/CS) pin out so that the DMA can't select the HDD.

[Icky]

So you get to the desktop at some point but with no drive showing (FDD and HDD) ?

Correct with HDD and Floppy connected it drops to desktop with no drives

[exxos]

My guess is some actual DMA bug, where the DMA is conflicting between floppy and DMA port... I found rdy pin was to blame before, but maybe it ultimately needs a new gate to only accept rdy to DMA when its not accessing the 1772... I'm thinking if end of a floppy cycle and DMA sees rdy at same time it screws up internally... Just thinking out loud.... So maybe worth checking rdy and 1772 cs lines at same time on scope and seed if they both go low at the same time at any point... Really that shouldn't happen.. But never feking know with this stuff... I will try some DMA probing when I get home tomorrow to see if I can find any odd looking timings..

[exxos]

Also could explain why on the ste the DMA port is delayed a clock cycle before data is allowed on bus...