On Wed, May 30, 2018 at 12:05 PM, Jon Elson <el...@pico-systems.com> wrote:
> On 05/30/2018 08:19 AM, Kyle Owen via cctalk wrote: > >> >> I'm thinking about trying to find a microcoded architecture to play with >> before I design something around the Intel 3000 series. >> > Intel 3000? WHY! > Well, the Tesla clones were cheap and readily available on eBay! :) > > I'd get an FPGA development board and download Xilinx's webpack software. > It would not take real long to design the basic microcode engine, and then > you could develop some application microcode in parallel with the hardware, > adding whatever feature to the hardware you needed when the need came up in > the microcode. Yup, I've played around a lot with my Basys 3 board. But I like the idea of writing microcode for an existing design (one that has a software simulation as well as real hardware would be preferable), even though it could likely run much faster on an FPGA. > > I've got a MicroVAX 3800, so I suppose I could run MICRO2 to assemble the >> aforementioned microcode. But then what? I assume PALs would have to be >> burned to implement the new microcode. Or is it more complicated than >> that? >> >> PALs? I don't think the 3800 microcode was in PALs. I think it was in > the CPU chip. There may have been a patch array that allowed a very small > number of microcode words to be overridden. Yes, you appear to be correct; it's all internal. Kyle
