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How to tell the extension what to do? I assume scanf will or work.

@zigzagjoe Are you able to let me know, how to make an extension from an standard app (output of C compiler/Linker)? I noticed, you removed all "print" statements from code. This might be a prerequisite but if I compile it is still and standard app. How to distinguish between early and late load?

As there is no 575 with me I just can guess: If I remember right, 575 does use MEMCjr memory controller and Gazelle clock generator as well. If someone has a schematic of 575 at hand you can check if Gazelle is used in the same way as in 475. For both I do not have facts at hand yet. If both...

Based on this document: https://www.nxp.com/docs/en/reference-manual/MC68040UM.pdf a heat sink and some airflow is required for 68040@33Mhz and above. See chapter 11.9.1 Page 11-17 ff If my understanding is right, TA shall not be negative. If you do not take care of this, the system may crash...

Any C Compiler should work.

Side note: This well-known page https://drive.google.com/file/d/0B9rTgRm4OkZwT2FDRjhqS2YzMFk/view?resourcekey=0-OlVMvZUf2Vvihc4bm1YHzQ report about screen resolution issues after changing in resistors for 33Mhz and lifting pin 9 of Gazelle and pull it to 5V using a resistor to achieve 40Mhz...

Omega does not seem to be as similar to the SC11412 as Gazelle. Omega might have 28 pins (based on LCIII schematics). Is there a datasheet for Omega?

Just to let you know, how to calculate parameters for "setlong" function. case 29: setregistermin(0); setregistermax(3); setlong(13,7,2); setregistermin(1); setregistermax(2); break; setlong expect 3 parameters...

Starting with the good news: Will work. But it is not only the "loading at startup" topic. When starting, Gazelle will read resistors and chose 33Mhz dataset from internal table (if resistors are changed for 33Mhz). When changing to to any value using the "setlong" function in my code, the...

All my tests until now were operating with 1152*870*8bit @75Hz using 60ns VRAM Right now I tested 640*480, 800*600, 1024*768, and 1152*870 @38Mhz with 80ns VRAM and 1152*870 @38Mhz with 60ns VRAM All of them work but switching resolution @38Mhz stopped with black screen. When first switched...

Checked with , Checked with Norton Sysinfo(Post #1), clockometer(Post#11) and Osziloscope at R96(Picture attached, frequency can be found at the bottom line of screen)

This side is telling: 343S0161 Gazelle Video clock generator, LC 475/575, Quadra 605 https://wiki.mamedev.org/index.php/Driver:Mac_68K:Tech_Info:ASICs#Off-the-shelf_ASICs No information about 343S1135 on that side. My LC475 has a 343S1135 Is leg 9 of U17 of non cooperative device lifted...

@Bolle Do you have RAM soldered to the board? This may limit RAM access to 70ns or 80ns. I assume there are different ways to disable those (remove chips, remove resistor in RAS line, change code in ROM)

Frequency can be set dynamically while running the computer. There are all frequency settings from 20 to 42Mhz in one 1Mhz steps in the code file. Others frequencies are possible but based on my current experience there are limitations (not above 38Mhz in my case)

V0.2 ready made. This version set all registers known from ROM and MEMCjr datasheet according to the tables in ROM and datasheet. All frequencies work for me. No crashes. Up from 38Mhz frequency does not increase any more. I assume something is not happy with those clock frequencies. First...

Attached what I was able to implement until now. This program expect desired frequency in Mhz as input and is able to set all CPU frequencies from 20Mhz to 26Mhz and contain multipliers/dividers up to 42Mhz. It does not update any of the registers that are set on boot depending of the starting...

My programming skills are not sufficient for an extention yet. I am able to provide a prove of concept someone else need to support to write an extention.

Setting CPU to any frequenz between 20 and 40Mhz work as well. I was able to verify with oszi.

There are two ways to set up Gazelle in LC475: Chose one of four preset frequencies 20Mhz, 25Mhz, 33Mhz, 40Mhz that is what I described above. Programm internal divider and multiplier. So you can implement a lot of frequencies. I did not tried this yet. My assumption of the difference between...

As you may know, a LC475 lives with me. My current target is to operate that LC at 40Mhz, so I read some pages about ROM hacking and MEMC chip. From the schematic I know LC475/P475/Q605 are using programmable Gazelle clock generator chip. Based on schematic and that document I learned that...