RC2014 "PRO" help

[Greg Peterson]

Gentlemen,

I am attempting to assemble a RC2014 "Pro" Z80 Kit from Tindie. Assembly is complete, the system powers up, FTDI issues have been resolved, and the SCM monitor boots and runs perfectly. A lot of major subsystem blocks have thus been wrung out. Communication is through TeraTerm on my desktop Win 7 64 bit machine. Tera Term has some quirks, but I have learned to live with them.

I am running the "DUAL CLOCK", "SIO/2", "Z80 CPU" "64k RAM", and "PAGEABLE ROM" modules on a stock "BACKPLANE PRO" board.

Jumper configuration is easiest to explain if we just start with no jumpers at all. Then add 7.3728 Mhz jumpers on Clock 1 & 2 on the DUAL CLOCK module. The +5 volt jumper on the DUAL SERIAL module is present as I am running the modules from USB power. The Z80 CPU module has no jumpers. The 64K RAM module is jumpered as per the silkscreen to start at 2000H, 8K up from 0000H. Note that the 64K RAM module "link" jumper is open. PAGEABLE ROM is jumpered for 8K page size as per the silkscreen, and page selection jumpering is A10, 11, &12 open, A13, 14, & 15 in a binary pattern to select one of 8 ROM pages, 32K Basic being 0, 0, 0. My "PAGEABLE ROM module" Rom chip, the AT27C512, is labeled 24886009. The "Decoding Rom Labels" data sheet states that a 2 (as is in the 1st (leftmost) position of the ROM label) Indicates "Microsoft BASIC, for 32K RAM, SIO/2, with origin 0x0000". Sounds like good to go, No?

My Problem: I can't get 32K Basic (1st program in AT27C512 Prom on PAGEABLE ROM module) to run. The Z80 basic (56K, 2nd program in Prom) runs like a champ, as does the SCM (3rd program in Prom). The last copy of SCM (8th program in Prom) also runs perfectly. The CPM monitor (5th) program refuses to run. So I am missing two programs that appear to have no obvious relation to each other.

I can live without 32K basic, though I would rather learn why it will not run, but no CPM monitor will be a problem.

I have dumped the AT27C512 contents on my PROM programmer, and Basic is there, at least there is lots of code present in the 1st 8K.

Before commencing assembly, I dumped the Prom contents & made a duplicate Prom. The two Prom versions match exactly, so I have not altered the Prom.

As I understand the system operation, the jumper settings on the 64K RAM module open a 8K hole in the memory map from 0000H to 2000H. Into that hole the PAGEABLE ROM module inserts one of 8 segments, each 8K in length, that it contains, selected by the A15, 14, 13 jumpers. 000 on 15, 14, &13 should select the 1st program in Rom, 32 K Basic.

I should also mention that I have a 512K Rom, 512K Ram module that runs, I assume perfectly. I do not know enough about WBW yet, but it puts up banners and answers to keyboard input.

I am to the point of running all IC chips through a logic checker, hoping to easter egg out a bad part. I have little hope though, as the monitor runs great through the same chips. I have pulled all the chips looking for a bent pin, no dice. I am also relatively certain I have no residual solder bridges from module assembly. Another approach would be to download a separate copy of 32K basic for the SIO2 and blow that into a separate ROM. I don't have a pile of Roms laying about with Tacc of 45 ns or better.

Any insights or troubleshooting directions would be greatly appreciated, I am growing weary chasing my tail on this one. I suppose it is possible I missed some errata info or addendum somewhere. If so, point me there. I am open to any troubleshooting ideas as well.

Thanks for any help offered,

Greg