There seems to be some confusion between Tiny BASIC and BASIC-52. Tiny BASIC uses Timer1, does not support the auto-baud, and defaults to 9600 baud. BASIC-52 uses the auto-baud (which will not work with the DALLAS Speed-up Micros) but can be configured for a fixed baud rate by programming fixed values for RCAP2.

I have modified these two programs for microcontroller products sold by BlueEarth, LLC

The original BASIC-52 was modified to access battery-backed RAM for "Saved" files rather than program EPROMs like the original Intel version. It supports config tags for fixed baud, BASIC program autoexec, etc. The Micros also include the 8K BASIC interpreter along with a full MONITOR-51 program in ROM. Makes for a great prototyping platform and development tool (Sorry for the shameless plug).

Many changes were made to Tiny BASIC including support for the (sadly discontinued) Xicor X88C64. The Xicor was a dual-plane architecture EEPROM, which allowed the TB52 program, located in the bottom 4K, to execute code to write to the upper 4K of the same chip! TB52 has since been updated to support the generic 28C64 (or 28C256).

Anyway, I have tried the 89C420 with both versions of BASIC. With no code mods to take advantage of the enhanced features, it runs quite a bit faster. However, I have been using Temic and Winbond chips, since they provide more bang for the buck. Plus I can actually get them! One of our older OEM products uses the DIP version of the 80C320, and we have had a few panic situations trying to get parts to build boards.