(Old) MIO 256K vs. 1MB Roms

[+Larry]

Has anyone ever looked at how closely these two roms were coded?

The units are essentially identical except for the difference in ram.

Thanks. -Larry

[Almost Rice]

Has anyone ever looked at how closely these two roms were coded?

The units are essentially identical except for the difference in ram.

Thanks. -Larry

 

We could probably check. I have a 1Mb MIO and Metalguy has 256k MIO with the same revison on the roms. We could look at it and see the difference. I just got the MIO so, I am still playing with it.

[+Guitarman]

I'm pretty sure that both models had the same rom. It was able to distingush the presence of the extra ram in the 1meg version. I once ask Tom Harker (ICD) and he seemed to remember just the addition of the extra ram and caps.

Edited June 8, 2006 by Guitarman

[sup8pdct]

I upgraded a mates MIO from 256k to 1 meg. I had to change the rom before it would see the 1 meg. I latter looked at the roms and found 1 byte difference (from a 40 yo memory). ie number of pages of ram to expect.

Not a fun job upgrading the ram either. Cleaning out many holes adding the Zipchip ram and then adding capactors to make the thing stable again.

 

James

[MEtalGuy66]

I upgraded a mates MIO from 256k to 1 meg. I had to change the rom before it would see the 1 meg. I latter looked at the roms and found 1 byte difference (from a 40 yo memory). ie number of pages of ram to expect.

Not a fun job upgrading the ram either. Cleaning out many holes adding the Zipchip ram and then adding capactors to make the thing stable again.

 

James

 

I second that... Saturday moring, I read in a ROM (version 1.1) from a 1meg MIO, and then read in a ROM (version 1.1) from a 256k MIO, and the checksums did not match.

[+warerat]

I upgraded a mates MIO from 256k to 1 meg. I had to change the rom before it would see the 1 meg. I latter looked at the roms and found 1 byte difference (from a 40 yo memory). ie number of pages of ram to expect.

Not a fun job upgrading the ram either. Cleaning out many holes adding the Zipchip ram and then adding capactors to make the thing stable again.

 

James

 

I second that... Saturday moring, I read in a ROM (version 1.1) from a 1meg MIO, and then read in a ROM (version 1.1) from a 256k MIO, and the checksums did not match.

 

What bytes were different?

[Stephen J. Carden]

I upgraded a mates MIO from 256k to 1 meg. I had to change the rom before it would see the 1 meg. I latter looked at the roms and found 1 byte difference (from a 40 yo memory). ie number of pages of ram to expect.

Not a fun job upgrading the ram either. Cleaning out many holes adding the Zipchip ram and then adding capactors to make the thing stable again.

 

James

 

I second that... Saturday moring, I read in a ROM (version 1.1) from a 1meg MIO, and then read in a ROM (version 1.1) from a 256k MIO, and the checksums did not match.

 

What bytes were different?

 

I have the source code to both rom's. and I do mean the real source from ICD they are not the same rom. The 256kmio and the 1meg mio are based on the same production run of boards. the 256kmio from ICD ran the best <really don't know why> the 1 meg MIO had the most returns from problems when they were built. The orginal rom's in the 256kmio were 2764 e-proms.. later run's when the 80col stuff was dropped they swaped over to a 27128k e-prom. Both devices use 192 bytes of setup that gets written to sector zero of a harddrive, and they are scsi I compatabale.. Somewhat. They only support 256 byte sectoring. in the Atari world the ICD mio was a second generation device. First generation was the Supra Interface latter to become KPI, MIO was the Second, Black Box was the third.

[ijor]

I have the source code to both rom's. and I do mean the real source from ICD

 

Would you mind post them, or otherwise could you PM them?

[Stephen J. Carden]

I have the source code to both rom's. and I do mean the real source from ICD

 

Would you mind post them, or otherwise could you PM them?

Are you a programmer? the source is still under copyright. And I do use a source save.. there are other that have the source.. or are you wanting a copy of the roms?

 

Steve

[mio2repair]

Hello,

Did anybody figure out the exact difference between the 1 meg and 256k

mio roms if any.

I need to figure out which one I have since my board was worked on before and it may be swapped from original.

Thank You

[Stephen J. Carden]

Hello,

Did anybody figure out the exact difference between the 1 meg and 256k

mio roms if any.

I need to figure out which one I have since my board was worked on before and it may be swapped from original.

Thank You

 

The source between the two roms are all most the same. The nearest I can tell the Difference between the two ROMS is when they are compiled. ICD used a real strange compiler even the source I have is hard to follow and then it is cripted during linkage. Here is how the roms go from source to image. The source is in XASM65.EXE cross-assembler it is assembled, Then it is LINKED using xlink.exe. I do not have any documentation on how either of these pc programs work. While I am sure I have all the source I am gonna have to convert it XASM.EXE to be able to make reasonable changes to it. The only plus here is I have documented source.

 

Steve