By Mike Wright for Cadd Electronics

PC99 Stage 5 product description 980201

PC99 is a program that emulates the Texas Instruments TI-99/4A Home Computer and selected peripherals. PC99 runs in protected mode under DOS, or in a Windows 95 DOS box, on an IBM or compatible 386 or higher PC.

PC99 features include:

TMS9900 16-bit processor: Fully emulated.

All 69 instructions and all corresponding addressing modes are implemented.

TMS9918A Video Display Processor: Fully emulated. Up to 16K VDP memory can be addressed.

Supports graphics, text, multicolor and bitmap modes, including so-called half-bitmap mode; and sprites.

TMS9901 Programmable Systems Interface: All of the features used on the 99/4A are fully emulated.

TMS9919 Sound Processor: Standard PC: PC99 only emulates TI sound channel 1. This is a PC limitation.

PC with Sound Blaster: Fully emulated.

Joystick port: Standard PC: Fully emulated using PC ALT function keys. PC with game port: Fully emulated.

Command module port: Fully emulated. Command modules" are DOS files. TI, DataBioTics, MBX, and Mechatronic bank switching schemes are implemented. GROMs: Up to 16 banks, each containing 5 8K GROMs, can be loaded. Multiple GROM banks are emulated using the REVIEW MODULE LIBRARY feature in the TI console.

TI 32K memory expansion card: Fully emulated. This peripheral contains 8K of low memory and 24K of high memory. All of this memory is treated as if it were on the TI fast 16-bit bus.

Myarc 512K memory expansion card: Full emulated. This peripheral contains 32K of memory which is used as standard TI 32K memory expansion. The rest of the memory can be partitioned into a 128K space for Myarc XB II, and a RAM disk and print spooler.

AMS memory card: Fully emulated. You can select whether to emulate the 128K, 256K, 512K or 1Mb version of the card depending on how much PC memory you have available.

TI disk controller: Fully emulated. The TI disk controller supports up to three drives. Each disk can contain 720 256-byte sectors, DSSD.

Myarc disk controller: Fully emulated. The Myarc disk controller supports up to four drives. Each disk can contain 1440 256-byte sectors, DSDD.

TI RS232 primary card: Fully emulated, if the PC has up to two COMM ports and one parallel port. PC99 can exchange data at up to 9,600 bps over the PC COMM ports, and can drive a TI compatible printer connected to the PC LPTn port.

TI p-Code card: Fully emulated. This card consists of a bank-switched 8K ROM and 8 6K GROMs and lets you run programs developed for the UCSD p-System.

TI Speech Synthesizer: Partially emulated. All of the software functions of the TMS5200 are fully emulated, but no audible speech is generated. This allows you to run programs that require the Speech Synthesizer.

PC99 "card": This is a software only "card", and was not an original TI or third-party peripheral. This "card" contains a DSR for the support of a real-time clock which emulates the CorComp Triple-Tech clock.

PC99 debugger: Displays a TI "Mini-Screen" surrounded by editable objects which allow you to control every aspect of PC99. With the debugger, you can stop any TI application at any time, including during disk access. You can single-step through any TI application, set breakpoints and watchpoints, examine and change any TI addressable memory, CPU, GROM, VDP, and command module space, and read and write the VDP write-only registers.

Command modules: TI Extended Basic, Editor/Assembler, Tombstone City and Mechatronic Extended Basic II Plus are included.

Documentation: Supplied on disk. PC99, and Myarc Disk Manager: about 150 pages in WordPerfect 5.1 and ASCII format. Myarc 512K card, Myarc Extended Basic II, and Mechatronic Extended Basic II Plus manuals are supplied in Adobe Acrobat pdf format.

Transfer Utilities: Allow you to move your TI-99/4A Command Modules and disk library to your PC. The utilities transfer binary images of TI disks, in both directions. You need a GRAM device, such as The Gramulator from CaDD, no longer in production, to convert Command Modules to disk format.

Standard Utilities: Allow you to: configure PC99; catalog TI disk files from DOS; extract TI files from TI "disks" and make them DOS files; take extracted TI files and convert them for use in PC programs, such as WordPerfect; and import TI files downloaded from bulletin boards or the World-Wide Web.

There are two PC99 products available: Full and Light. The Full product is the equivalent of: 1) A TI-99/4A console with choice of TI or OPA ROMs and GROMs and support for up to 16 GROM-based command modules. 2) A Peripheral Expansion Box containing a TI 32K or Myarc 512K or AMS memory card; TI or Myarc Disk Controller; TI RS-232 card; TI p-Code card; and PC99 "card" (real-time clock). 3) A TI Speech Synthesizer (speech functions work, no audible speech is produced). 4) TI Extended Basic, TI Editor/Assembler, Tombstone City, and Mechatronic Extended Basic II Plus command modules. In addition, you have access to the PC99 Mini-Screen debugger.

With either PC99 product you can run TI-99/4A Command Modules and disk-based programs with few limitations. Each product includes files containing all necessary ROMs and GROMs.

WARNING: There is no guarantee that any further development will take place after Stage 5. Please understand this before placing an order.

Cadd Electronics
45 Centerville Drive
Salem
NH 03079-2674
603-895-0119, 603-893-1450

FAQ courtesy of Dan Eicher