glb_gtz's blog

It is alive

Well...mostly. Yesterday it looked like it was trying to boot. I was getting a ] at the bottom of the screen when I hit the RESET button. But the screen would not clear and the keyboard was not working. I should have cycled power and I would have gotten the screen to clear. Something about cold booting and warm booting. Today I fixed the keyboard, except for the space bar. And now I can run BASIC programs. I have not done much testing, but I have some issues that I need to fix. Of course, I need to fix the space bar. Also, the character K is replaced with G. Both if these are easy fixes.

Close but no cigar

Even a near miss is still a miss. I have not gotten the system to boot. I have all the Apple ][+ memory map finished. I also added some of the 2e stuff. I am having problems with the LPC ROM, of course. Debug is going slowly. In the process of looking at the memory map, I noticed a few things that I had forgotten. My original plan was to use RAM for all the ROMs. When I was looking at some of the aspects of the Language Card, I noticed the 4k block that needed to be relocated from C000 to D000. It is weird that I do not remember that feature from my old Apple hardware.

How slow is too slow?

In my debug of the Verilog 6502, I noticed that the code was not cycle accurate with the NMOS 6502. A lot of common instructions take an extra cycle. The means that most of the time it will be running 25% - 33% slower. For me, that is unacceptable. I have been playing with writing a cycle accurate version. It is doable, but it will take a lot longer. So I am going to put that on the back burner in favor of getting the APPLE to boot. I will have to make sure I use just the 6502 ROMs.


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