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Cheapo IDE interface for Model 4p running MM CP/M

Nice one! How much RAM does the driver need?

The board protection issue has been bothering me; I realised that the protection previously described would need to be implemented in the cable rather than the board, which of course I have no control over. So I've re-worked it for what I hope will be the last time, replacing the second ACT32 with an ACT241 and making use of the TRS-80 pin 45 which is N/C.

So the protection (against the TRS-80 expansion cable being attached backwards) is to route /EXTIOSEL line through the ACT241 second channel, which is enabled via a 10k PU on expansion header pin 45. If the cable is correctly attached all will be well, but if the cable is backwards pin 45 will be ground, meaning the ACT241 second channel would be left in high-Z state.

Anyway archive updated in case anyone fancies a look. I'm intending to order the PCBs tomorrow so please be quick if you spot anything that needs amending!
 
Well I am leaving the board as is. Not adding anymore chips mainly cause it works for me. Also pin 45 is not hooked up at all inside the Model 4. Just a pin that does not go to anything. Its a dead pin if you will. A trace and that's it. Plus as I mentioned my cable is weird that's all. Your board should be good as it is. And if it looks like the one I have a picture of in a previous post all should be well. The one trs-ian is selling!
 
Ok Matt's updated drivers are working fine. WooHoo way to go bud...As they say a picture is worth a 1000 words. well here ya go folks LDOS working and I created 3 logical drives but you can always add more!

Here is a sample of the LDOS/TRS-DOS 6 command to create logical drives.

system (drive=x,disable, driver="hddvr6/dct") where x is the drive letter you want to create. Usually start at 4 and increment from there. As you can see in the pics I have drives 4,5,6. This is just a quick example.
 

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Now booting from CF card with a boot disk. The Model 4 can't boot from a hard drive unless it has updated ROMS I think. But the 4p can but not sure how it does it. So drive 0 is CF card as is drive 1 also drive 2. Drive 3 is bottom floppy and drive 4 is top floppy. Now try not to get confused with that setup! Just a test I was running. According to the HD drive manual you can set up 6 logical drives on the "hard drive".
 
Pearce: Just a thought maybe add an on board 5v regulator? 7805 with supporting caps etc. Then can use any DC power supply like a 12 or 15 volt unit. I added one to my prototype and usually add to all my stuff. Just a thought totally up to you to add.
 
Chromedome45 said:
Now booting from CF card with a boot disk. The Model 4 can't boot from a hard drive unless it has updated ROMS I think. But the 4p can but not sure how it does it. So drive 0 is CF card as is drive 1 also drive 2. Drive 3 is bottom floppy and drive 4 is top floppy. Now try not to get confused with that setup! Just a test I was running. According to the HD drive manual you can set up 6 logical drives on the "hard drive".
Click to expand...

I can answer that...as I have a working GIDE setup on mine...

It senses the presence of the controller on the $Cx I/O lines and attempts to find HD0... reads the boot sector if available and boots to it.

I had to modify the boot sector data to compensate for differences between MFM and IDE statuses, but it boots just fine!
IF the interface is being recognized by the 4p, you need only CONFIG a system onto the HD0 ** AS A: ** (CP/M) and it will work.
If you don't make HD0 drive A: then once it boots up it will expect a floppy ALL the time.

:D
 
Not necessarily...

F1 will force HD boot... F2 forces FD boot...

'.' on powerup enters a SERIAL BOOT MODE (IIRC)...

There is a memory test too... but I cant remember it right now. :D
 
Chromedome45 said:
Pearce: Just a thought maybe add an on board 5v regulator? 7805 with supporting caps etc. Then can use any DC power supply like a 12 or 15 volt unit. I added one to my prototype and usually add to all my stuff. Just a thought totally up to you to add.
Click to expand...

I had a similar thought… I've added a mini USB port, I figured most users would likely have one lurking in a drawer somewhere. With a pin20 powered compatible CompactFlash header, this shold power the media too.
 
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