About
The programs from Einstein User's September 1986 issue, on one bootable Xtal BASIC disc. This is the issue for anyone who wants to see what the machine's sound and sprite hardware will do.
Nigel Deakin's Drum Machine lays a 32 beat bar across the screen and plays it from the Einstein's timer chip, with side drum, snare and cymbal at any tempo. It is here with the one misprinted byte that silenced it corrected, alongside the listing as printed. Page 13.
His PSG program puts every register of the sound chip on screen so you can move onto any bit, set or clear it, and hear what it does. Page 14.
Mark Bailey's four sprite demonstrations show the five sprite limit with the fifth vanishing, all sixteen colours, a four colour 16 by 16 super sprite, and a walking man in two colours. His machine code from BASIC article is here as a working nine byte keyboard poll with the BASIC that loads and calls it. Pages 16 and 31 to 32.
And XBAS80 is Xtal BASIC 4 patched for 80 columns as Roy Clarke and Nigel Deakin's article instructs. Page 32.
Running them
Boot the disc, type XBAS, then LOAD "DRUM2" and RUN. Keys 1, 2, 3 and full stop lay out the bar, SPACE starts and stops it, and U and D change the tempo.
What is in the download
A zip holding the disc as a DSK, the same disc as an MFI for MAME to write to, the listings as BASIC text and as tokenised Xtal BASIC, and a README.
Verified
Run in MAME 0.289 with Xtal BASIC 4.2 and MOS 1.2. The sprite attribute tables were read back from video RAM and match every listing. The keyboard poll puts the key's code where the article says and moves the sprite over the key pressed. The sound chip keystrokes set and clear the predicted register bits. As printed, the Drum Machine leaves its beat pointer stuck and never touches the sound chip; the corrected copy runs the bar and writes each hit. The sound was read from the emulator's registers rather than listened to. XBAS80 needs the 80 column unit and could not be tested. Not run on real hardware.
The scanned issue is on this site as Tatung Einstein User Vol.2.No.3.
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