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Some progress for FreHD on model 2

V

veco

Experienced Member
Joined
May 12, 2013
Messages
95
Hi folks.

Wanted to share some progress. I have hacked mame to support FreHD on the model 2, so I can understand what's going on (since my model 2 has a broken floppy disk and no hd interface card). FreHD will require a little mod and a new GAL to work on the model 2, Hans and I are working on it.

Long term, I plan to make a model 2 board with 512K ram, 512K flash, and a FreHD v2 (based on a PIC32 + big CPLD to implement some required logic (CTC and DMA support)). Maybe memory for 68K ? We'll see...

-Fred
 

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TRS-Ian said:
Hooray! That's great work Fred :)
Click to expand...

Yes, you helped indirectly. I got the schematics from Pascal who also helped, which he could do with the board you sent him a while ago :) Team work !
 
Great news! Do you expect the modified units to become incompatible with the Model III/4? I think I should order another FreHD from Ian with plans to modify it later, and make sure I have the right GALs in my parts bin.
 
NF6X said:
Great news! Do you expect the modified units to become incompatible with the Model III/4? I think I should order another FreHD from Ian with plans to modify it later, and make sure I have the right GALs in my parts bin.
Click to expand...

Yes, the GAL has to be different because address 0xC2-0xC7 cannot be used. FreHD, on a model III/4, uses these to give extra functionality. On the model 2, these addresses are used by the CRC (C4-C7). C2-C3 are "id registers", but I haven't seen code accessing them yet. I also haven't seen any DMA done with TRSDOS 4.0, but I have just barely tested it on the emulator. I'd be nice to boot cp/m and later xenix but if I design a board, there will be enough space on the CPLD to accommodate DMA.

-Fred
 
Any chance you could put an Ethernet or WiFi module on the board? I know it’s a big ask but there are a lot of uses for Network connectivity.
 
veco said:
hi folks.

Wanted to share some progress. I have hacked mame to support frehd on the model 2, so i can understand what's going on (since my model 2 has a broken floppy disk and no hd interface card). Frehd will require a little mod and a new gal to work on the model 2, hans and i are working on it.

Long term, i plan to make a model 2 board with 512k ram, 512k flash, and a frehd v2 (based on a pic32 + big cpld to implement some required logic (ctc and dma support)). Maybe memory for 68k ? We'll see...

-fred
Click to expand...

this is proof that the trs 80 is somehow still a machine of viable interest to people out there - so try and attend tandy assembly 2018 to help keep the trs alive !!!!!!!!!
 
Jay Newirth said:
this is proof that the trs 80 is somehow still a machine of viable interest to people out there - so try and attend tandy assembly 2018 to help keep the trs alive !!!!!!!!!
Click to expand...

I will be happy to demo this on my Model II exhibit at TA if it is ready.
 
The first working FreHD2.

We all worked together to achieve this result.
Pascal did a great job on the hardware, Fred did a perfect job on writing and debugging the new firmware for the FreHD2 and I did the
testing of the hardware, software and the final result.

Fred has made it possible to have his FreHD working on the Model II family with small adaptions, you need some small patches on the hardware, you need a new GAL and PIC and there is a new VHD format.
There is one setback, you need a MODEL II harddisk adapter type 2 to interface the FreHD2, but we are talking with Pascal and Ian for a solution.

We proved that it is possible to have an affordable harddisk on your Model II family, but be patient there has a lot to test before it will be available for all.

Thanks to Fred, Pascal and Hans.

WP_20180712_08_48_35_Pro.jpg WP_20180712_08_49_08_Pro.jpg WP_20180712_08_49_57_Pro.jpg
 
Great work, boys! I'm looking forward to playing with the FreHD II.
 
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