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Texas Instruments HX-5102 Disk Drive / Controller

Date of introduction:  Never
 (Announced: 1983)
Display technology:  
New price:  t.b.d. Display size:  
Size:  t.b.d. Printer technology:  Ball point Pen
Weight:  t.b.d. Serial No:  
Batteries:   Date of manufacture:  
AC-Adapter:  AC9610 Origin of manufacture:  Japan
Precision:   Integrated circuits:  
Memories:   HEX-BUS Device ID:  101-104
Program steps:   Courtesy of:  Joerg Woerner

Texas Instruments designed in 1982 with the HEX-BUS a very innovative interface to connect intelligent peripherals like printers, modems or even a video interface to its new Compact Computer System CC-40 and planned to use it with the never released TI-99/8 home computer.

The physical interface of the HEX-BUS is a rather simple 8-pin connector and with peripherals having always two HEX_BUS ports, multiple peripherals can be connected in a daisy-chain mode. The Hardware of the HEX-BUS uses four Data-Signals [D0, D1, D2, D3], two Handshake-Signals [HSK], [BAV] and a common ground signal [GND]. The remaining line was reserved for future use and labeled [FUT]. With the drivers being "open collector", the interface allows bi-directional data communication, each Byte is transmitted in two 4-bit words in a Master/Slave protocol. Texas Instruments published not only the specifications of the HEX-BUS and the software requirements for peripherals, but even offered two different Intelligent Peripheral Bus Controllers (IBC), realized as ASICs (Application Specification Integrated Circuits):

TI # 1052911, LSI Logic ASIC L1A0037, 22 pin Package
TP0370, new version, 28 pin package

Texas Instruments dropped out of the home computer market in March 1984 - after selling more than 2.5 million of the famous TI-99/4A - and production of the CC-40 was ceased immediately after. Consequently was the development of the HEX-BUS terminated and only a few of the already announced HEX-BUS peripherals were manufactured in significant quantities. Interesting fact to know: The TI-74 BASICALC and TI-95 PROCALC computers introduced in 1985 as successor of the CC-40 use a 10-pin Dock-Bus which is compatible to the HEX-BUS and added three signals: [RESET] and System Power Distribution In [PI] and Out [PO] to power peripherals from the computer or the computer from peripherals.

Texas Instruments announced or released during the short live of the Compact Computer 40 eight different products like printers, plotters and even a serial interface using the HEX-BUS Interface. Additional peripheral devices were planned or released from Third Party vendors but are not listed as of now in our overview:

Part

Name / Description

MSRP (1983)

Status

HX-1000 Printer / Plotter 4 colors $199.95 Series
HX-1010 Printer 80 (Thermal ribbon) $249.95 Series
HX-1100 Video Interface $99.95 Prototype
HX-2000 Wafertape Digital Tape Drive $139.95 Prototype
HX-3000 RS-232 Interface $99.95 Series
HX-3000/P RS-232 + Parallel Interface $124.95 Series
HX-3100 Data Modem $99.95 Series
HX-5102 Disk Drive/Controller t.b.d. Prototype

Texas Instruments announced with the HX-5102 Disk Driver Controller an external DS/DD (Double-Sided, Double-Density) 5¼" floppy drive with a controller for up to four drives. It connects with the HEX-BUS Interface to the Compact Computer System CC-40 and other devices supporting the HEX-BUS specifications.

The HX-5102 Disk Driver / Controller was unfortunately never released and only a few prototypes are out in the wild.



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If you have additions to the above article please email: joerg@datamath.org.

Joerg Woerner, October 25, 2019. No reprints without written permission.