Exploring the Microprofessor

My next video about the MPF-IP is online! This time, I am demonstrating the BASIC by computing prime numbers with the sieve of Erastosthenes. Also, I pulled the cassette recorder from the garage, so this is going to be fun too. Next, I am comparing the MPF-IP's BASIC performance with the ZX-81, running the same program. Which machine is going to be faster - ZX81 or MPF-IP?

Preparing for my demo video of the MPF-IP BASIC, another Microprofessor MPF-IP enthusiast I was chatting with on another forum just complained that his BASIC wouldn't print properly beyond 18 characters, and that certain BASIC statements documented in the manual don't work (SON, SOFF).

I said, what do you mean? My BASIC just works fine, no issues with the printer, and SON / SOFF work flawlessly!

He then pointed me to the BASIC ROM image he was using: 

https://electrickery.hosting.philpem.me.uk/comp/mpf1/doc/MPF-IPlusBasicROM.zip

I grabbed it and burned an EPROM, and indeed - this version must be a prior version and has these issues! For printouts, you'll have to limit yourself to 18 characters per line, else your printout looks as follows:

Now, my original BASIC ROM is indeed working fine, has SON / SOFF, and printing works fine beyond 18 characters: 

Seems the MPF-IP BASIC got a major update. There is no obvious version number encoded in the ROM image (at least not in ASCII).

Comparing the ROMs a bit, I see that they even omitted the READY prompt in order to accommodate the patches and SON & SOFF... the new version goes to 0x1ff8, whereas the "buggy" version has 0x1ff3 as last address. So a few bytes more. They really used almost all of the 8 KBs in the 2764!

Looking at my MPF-1B pictures and videos you may have noticed that my MPF-1B didn't have the (optional) Z80 CTC and Z80 PIO installed. They just arrived! Plugged them in and keyed in Experiment 15 from the Experiment Manual: Clock 2 with CTC Interrupt Mode 2, and it worked!

https://electrickery.hosting.philpem.me.uk/comp/mpf1/doc/MPF-1_experimentManual.pdf

Good to know that I didn't get fake chips this time - I was skeptical, because they look like new. Phew!