TID: Mystic BBS 1.12 A46
MSGID: 1:387/26 9ddc34c0
REPLY: 1:18/200.0 60de289c
TZUTC: -0500
On 01 Jul 2021, Sean Dennis said the following...
 SD>  JT> Here's the current state of my PDP-8 FPGA project:
 SD> 
 SD> That's really cool.  The oldest computer I've used is a VAX.

I worked with DEC Alphas for a few years, but have only encountered
architectures older than that as a hobbyist. SIMH will emulate a VAX, but the
problem is in acquiring the OS. HP (which bought Compaq, which bought DEC)
still requires a license to use VMS. Up until fairly recently they had a
hobbyist program through which one could get a non-commercial hobbyist
license for free, but they discontinued it. I'm not sure what, if anything,
took its place.

I completed all but the Extended Arithmetic Element opcodes yesterday; it was
much easier than I thought it would be.

I have, however, run into a small snag. The Mojo IO Shield uses all of the
available IO pins, so there are none left for peripherals such as an SD card
or a serial port. I figure I have 4 options:

1. Try to use IO pins for unused switches or LEDs, despite those components
being hardwired in;
2. Make a new fron panel from scratch with only the necessary components
(which I could, of course, make any size and with any layout that I'd like);
3. Forgo the front panel altogether; or
4. Move everything to an Alchitry Au/Au+ FPGA board which has more IO pins
and a virtually identical IO shield, but is physically almost ridiculously and
unusably small.

Jeff.

"For every complex problem there is an answer that is clear, simple, and
wrong." -- H. L. Mencken, who indeed was a racist thereby proving himself
right.

--- Mystic BBS v1.12 A46 2020/08/26 (Raspberry Pi/32)
 * Origin: Cold War Computing BBS (1:387/26)
SEEN-BY: 1/123 14/0 18/200 19/25 33 38 50 90/1 105/81 106/633 987
SEEN-BY: 120/340 123/131 124/5014 5016 129/305 130/803 154/10 203/0
SEEN-BY: 221/0 226/30 227/114 702 229/101 424 426 428 452 700 981
SEEN-BY: 229/1016 1017 240/2100 5138 5411 5824 5832 5853 249/1 206
SEEN-BY: 249/317 400 261/38 280/464 5003 282/1038 288/100 292/854
SEEN-BY: 301/1 310/31 317/3 320/219 322/757 342/200 387/25 26 396/45
SEEN-BY: 423/120 460/58 633/280 712/848 770/1 2452/250 2454/119
PATH: 387/26 396/45 280/464 240/5832 229/426