Mega ST and TOS 2.06 decoder board

Upgrade or replace the ROM.
coonsgm
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Joined: Sat Jan 30, 2021 1:30 am

Re: Mega ST and TOS 2.06 decoder board

Post by coonsgm »

Just curious, @PhilC were you able to get the decoder running on all 4?
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PhilC
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Re: Mega ST and TOS 2.06 decoder board

Post by PhilC »

@coonsgm yes it worked on all four in the end
If it ain't broke, test it to Destruction.
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PaulJ
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Re: Mega ST and TOS 2.06 decoder board

Post by PaulJ »

Well I received @coonsgm TF536 board and decoder I purchased from him. I removed Trudie 5.2, the 68k and plugged in the decoder and 536 into the H4. First try and it booted right up EmuTOS 0.9.2. Gotek and 536 IDE both work fine with what was previously loaded on the devices. Also its running off the 27c400 emulator which lets me cycle through a variety of TOS’s. I included a picture of the Bench6 run. Guess I'll have to get busy and add the stuff to move stuff to alt ram.
IMG_2665 (1).jpg
IMG_2665 (1).jpg (285.03 KiB) Viewed 2525 times
IMG_2664 (1).jpg
IMG_2664 (1).jpg (257.1 KiB) Viewed 2525 times

So I had to wonder what the issue was with Gregs Mega attempt so I took a look at the Mega's TOS adapter board that was being used by Greg. I don’t know for sure but I suspect all these adapters are the same and I have a couple I no longer use. The ce pins are NOT connected together on the adapter board but have a common trace on the mega’s motherboard so they show 0 ohms if you check the resistance while the boards is inserted. Remove the board and the ce’s are not connected together. The 16 bit eprom on the adapter gets its ce signal from the left hand chip socket which is next to the 16 bit rom. The right hand sockets ce goes no where on the adapter so can be ignored. You must pull the ce pin on the left hand socket so when you connect the new decode line it will not conflict with the glue’s decode signal coming from the motherboard. The motherboard will not decode $E00000 and the new decoder will so they will be fighting each other and hence you will have issues.

I’ve been playing with the board and it work pretty good. It even runs the netusbee without issue and it appears to be faster which doesn’t make sense. Couldn’t find anything that doesn’t run yet.
coonsgm
Posts: 152
Joined: Sat Jan 30, 2021 1:30 am

Re: Mega ST and TOS 2.06 decoder board

Post by coonsgm »

I’m really glad you’re getting use out of the TF536...those results look fantastic. Thank you for sharing what you’re finding!
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