NM this question. I think I have gotten a handle on it now. The FlexROM 100 replaces the main system ROM (only really useful for my M100 with the non-standard socket)
The Rex is an option ROM replacement that allows me to store several option ROMs at once and also allows me to store my own programs in flash. With the two together, they form the system you are all describing. In reading the Rex# instructions, it doesn’t appear that I need to call it to get it started (even without a flexROM?) Thanks again. I am slowly getting up to speed here. I am sure my questions look ridiculous to you silverbacks. As I mentioned, the Model 100 is a completely new system for me. It’s whole universe is still foreign to me. I’ve never even used a TRS-80 of any sort before. Scott From: Scott McDonnell Sent: Saturday, December 19, 2020 6:35 PM To: m...@bitchin100.com Subject: Re: [M100] Model 100 Repair - Keyboard not responding,LCD missing a column Will do. Just so I understand, the Rex replaces the main rom? The M100 will boot directly from the Rex? And with the Rex, I can customize my own applications, autolaunch, etc? This goes into the DVI socket on the bottom? I had looked at it before, but the descriptions seem to be written for people that are already well into the Model 100 and not very clear to a TRS-80 newbie like me. :) What I would like to be able to do: Replace the main ROM Custom menu My apps not stored in RAM dependent on battery Autolauch a program at power on (and preferably be able to exit out to menu if wanted) Ease transfer of files back and forth with a PC (TPDD emulator or Trashtalk) Thank you to everyone that has replied. From: Stephen Adolph Sent: Saturday, December 19, 2020 6:27 PM To: m...@bitchin100.com Subject: Re: [M100] Model 100 Repair - Keyboard not responding,LCD missing a column Scott, I recommend before you jump into a REX solution that you read my REX# and REXCPM wiki pages at Bitchin100. REX Classic is the DIY option, but I no longer support it, and it has known defects. My 2 cents as the designer... Steve On Sat, Dec 19, 2020 at 6:12 PM Brian White <b.kenyo...@gmail.com> wrote: Actually with rex classic you don't even need any rom in the main rom socket so you don't need any of those boards, just a single wire from the /CS pin in the main rom socket out to the REX. You just can't run the machine *without* the rex after that without opening back up to put a rom back. The flexrom board just lets you install or remove the rex at will, as well as being re-writable itself by being a 28C256. On Sat, Dec 19, 2020, 6:04 PM Brian White <b.kenyo...@gmail.com> wrote: On Sat, Dec 19, 2020, 2:38 PM Scott McDonnell <mcdonnell.j...@comcast.net> wrote: Now that I have proven out that a 27C256 EPROM is working fine in this one, I am going to play around with customizing it. The real ULTIMATE would be to replace the ROM with an EEPROM (like 28C256) and add in some type of loader where you could update the main firmware over serial. That may not be possible because often in these 80’s computers they usually placed some IO address space in the ROM area (since write is not possible to the ROM) and decoded it using the write signal and address. It was a simple trick for accessing output only IO. I am talking out of my rear end right now because I haven’t studied the schematic/memory map in detail yet. http://tandy.wiki/FlexROM_100 http://tandy.wiki/FlexROM_102 Especially in concert with REX Classic http://tandy.wiki/Building_a_REX or arcadeshopper.com sometimes has rex classic pre-built you can just buy. You'd use the FlexROM_102 in the 100 that has the standard pinout. If you don't care about using the fully software loadable main rom via REX, and only need a plain 28C256 to 27C256 adapter without the /CS breakout remote loop, this would be a bit more convenient because it doesn't need a soic-28 test clip to program it. http://tandy.wiki/28C256_to_27C256 You just switch a couple jumpers and pop the board right in the programmer.
