Atari-Forum

Indeed, faster is not always better. If memory serves right, F and HCT are equally fast in this 244 buffer type. The signal names in an earlier post should tell the significance of the signals. AS stands for Address Strobe. UDS and LDS are Upper and Lower Data Strobe. RW is Read Write. These signals...

Yes, You're right. The tester will tell you if the IC is a 74xx244. If not, it will detect it as defective or maybe another function. Of course it's not so simple to check if any TTL IC is F, or LS or S. An Eprom programmer is not equiped for that. Unfortunatelly, it may even be so that only one or ...

The TT actually has 4 serial ports. Or even 5 if you count the Micro-wire port also. 2 serial ports are made the same as in the ST. And 2 are done with a uart, the Z8530. I would strongly suggest to have a look at the schematic diagrams of the TT before you start. And google for the "Z8530 datasheet...

For restistors, the Ohm value is very important. But the wattage is not so much so, with one restriction. A smaller wattage will not be able to desipate the heat. But in this case, the bigger the better. Only restriction is the size. And it also helps, to mount them a bit free of the bottom, so they...

Hello Antibaddy, If you have 2 (almost) identical computers, you have a big advantage. This gives the possibillity to use the working computer to test parts. This is not 100% safe, but very little risk actually. Apart from maybe the OS, (these may be of different level of revision), you should test ...

Hello,
According to my schematis and layout, it's U206 and that's the MCU.
Can't find the chip number right now. (The chip is below the casing for the VME-Card.)

Frank Lukas has (almost) made an adaptor like this.
It should not be difficult to change the PCB he made, to use the plug.

BR/
Guus

Thanks for the efford of making this hardware. :-) Veru curious about the price...... As for the question of IDE for all models: It would enable me to take one CF-card and use that on all models. This is a very nice way to exchange a lot of data at once. So use a relatively small card to boot from a...

So please post those sources and the hardware schematics for it.
I'd like to see if it's usefull for me.
And the compiled usable version would also be a great plus.

Hello Alanh, I am able and willing to help out. I've build quite a number of MegaSpeedy PCB's for the Atari 8 bit. That has a Xilinx XC 95144 and I hand soldered those. The only thing that can be a setback, I'm in the Netherlands and postage is not so cheap. PM me if you see some possibilities. BR/ ...

Some help, pointers and considerations are welcome. What I want to find out is an optimum in configuring the CF-cards that I can use on the TT. I have a number of 4GB-cards. And I would like to exchange software from a PC and maybe also with a Falcon. So the card should have a partion for PC as well...

Hello, A short while ago, I replaced the RTC on 4 Falcons. The RTC's came from Mouser and were sure to be new and good. But on 2 boards they didn't work, the boards would not boot with the new Clock. When the old IC was put back, it worked just fine again. However, a solution was found. The Falcon w...

Hello,

To test, just switch it on.
If it's ok, then it will work. (Obviously)
If the vacuum is gone, it just won't work.
Mostly, the front won't look nice and even if the vaccum is gone.

BR/
Guus

Hello Foxie, What I can see in the schematics is that the LDS signal is used as a clock to 74F74 FF's. A signal called SEM is delayed by one extra FF that's also clocked with the LDS. So it looks like the complete access cycle is delayed to give the Midex a bit more time to finish a cycle. Maybe slo...

Hello Foxie,
Yes, I did figure out (for a bit) what it does.
It inserts an extra wait-state in the handling of a command.
BR/
Guus

Hello, Does anyone have the MROS files from Steinberg that work on a Falcon? I've tried to modify a Midex+ to run on a Falcon. But the testprogram keeps telling it cannot find a file in the MROS folder. The modified Midex doesn't work on a Mega ST anymore. (But can be made switchable real easy.) BR/...

Hello Foxie, The full schematics in a four sheet PDF, sometimes a bit hard to read, but ok. And the Jedec files for the main GAL, as well as the data to create this GAL. (20V8) And the Jedec file for the SMTP-Gal, a 16V8 So in my opinion, enough to recreate a Midex+ expander. Just let me know an E-M...

Hello, Would a Steinberg Midex+ interface do the right job? As it happens, I do have a lot of data on that. There's the schematic diagrams, GAL files and data for the modification. (Originally the Midex has PAL's) And there's a document for a Falcon mod. (That I've not tried yet) Also, I have test p...

Hello Artik-wroc,
Have a look at the cabling for the power supply.
Specially the minus needs to be very big, large surface.
Memory creates spikes in supply voltages.
BR/
Guus

Hello Olverg,
It is possible to use FPU or CPU at lower speed. Also at different speed.
Like CPU @ 33Mhz and FPU @50Mhz or even 66Mhz, overcolcing a FPU is often no problem.
And the 68000 family is A-Syncronus, so no problem.
BR/
Guus

Hello clh333, Normally, removing all the screws that are in a "square hole" will enable you to take an Atari computer apart. For the Mega ST, lift the back as far as you can and try to slide the plastic to the front. This will enable you to move it past the front of the floppy drive. It helps to ins...

Really nice.
I want to buy one.
For some reason the PM's I write are still in the outbox and apear bot to be sent.
Can you please try to contact me?
Thanks.

It may help to replace the 74LS244 and 74LS373 by a couple of F-types.
This makes the access to Ram a bit faster and often more reliable.

The PAK always needs the ROM's in the MB to start.
It uses the reset vector in these.

BR/
Guus

My 4 CPU's:
68020RC16B 2A70N8633
68020RC12B 2A70N8747
These 2 work fine in the booster20

68020RC16B 2A70N8807
68020RC12B 2A70N8633
Don't work in the Booster20 but are ok in the Pak68/2
BR/
Guus

The Booster020 works fine with a blitter. I have two 020's and tested in 5 individual MegaST boards. These are of various revisions, 1MB, 2MB, 4MB with different chips. Also with IMP chips. Maybe the combination with 16Mhz is not ok for the blitter? And not all CPU's work fine. Out of 6, I only had ...