
this is the 3rd version of my computer, functionally not much has changed since last time but there have been a few changes:
more ROM
new memory controller, uses less space and is faster, but currently bugged (i built this last night and didnt fully test it :S). bugs that i have fixed since uploading this include:
the 1st byte does not clear properly. this can be fixed by putting a repeater onto the clear control line to add an extra delay, putting the signals in sync.
the second byte does not output. this is because the signal from the controller dies before it reaches the output. this can be fixed by adding a repeater onto the control line.
the 3rd byte does not work. this is because the clear line circuit isnt finished (as i said, no testing :3), so it clears after every operation performed on it. this can be fixed by extending the clear control line located beneath the memory controller from the first and second bits out to the third, and placing a torch as is placed in the other examples.
other than that, there havent been many changes. ill put the instruction set below for conveniences sake:
(from the left)
1 = control bit, 0 for number, 1 for instruction
2 = mem address bit value 8, currently not used
3 = mem address bit value 4, currently not used
4 = mem address bit value 2
5 = mem address bit value 1
6 = mem write bit, write current CPU output to the addressed mem byte. toggles screen output if mem address = 0
7 = mem clear bit, clears the addressed mem byte, or cache if mem address = 0
8 = mem read bit, read addressed mem byte into selected CPU cache. toggles cache if mem address = 0
and thats it, other than the things noted above everything should be in working order, but if you do find problems please let me know in the comments. suggestions/criticisms also welcome :)
*EDIT* actually after further investigation, there are a lot of synchronisation problems with the memory controller. ive fixed them now, and theyll be in the next upload. couldnt tell you when that will be though, this ones map only just finished rendering :P