Recreating Woodstock (67)

[Alejandro Paz(Germany)]

Hello,

like some of you know, I've been working on a re-implementation of the Woodstock class machines. I started with the 25 and later jumped to the 67. After several prototypes, I settled for a landscape layout similar to those of the voyagers. My preference, I wanted a development platform that reflected a bit more what I think is the best layout in terms of, I don't know, I just think they fit better in a cramped desk like mine ! .

I'm writing a logbook about the inner workings of my particular implementation, it is not bit serial it is nibble serial and the rom word is read at once. It doesn't make it any less difficult, I think.

I went with a Lattice MachXO2-7000ZE for low power, and while it is lower power than the 67, at 7 mA, it is in no way what I wanted, I was expecting uA level consumption. I'll have to explore other clocking mechanisms, I'm using the internal clock generator, to try to lower consumption. On-Off is something that I haven't researched well yet. The 67 turns completely off when... off ?... The others (voyagers) have built-in sleep mechanisms.
There are other alternatives like the iCE variants, nowadays there are like 5 families ! with very confusing names.... they should be a bit less hungry, and the 67 should fit in 1280 LUTs when the trace unit is not synthesized. But it needs 6 block rams for microcode and registers.

I'll re-post the code-base on github, I removed the old code as it is already two generations old, so to say. I re-wrote most of it a couple weeks ago.

In case someone asks: A replacement board for the 67 is something I thought about, I just do not want to use my only 67 as a ginny pig, it works flawlessly, well not so as the card reader never ever worked, not even in the old days (89-90).
I even got a replacement, damaged 71 after begging and more begging, and some dancing around a camp fire with a stone axe.... Maybe someone has a corroded one that could be lent for a brain surgery