GLaTICK

(Generational Logic and Time Interval Cadence Knower) ^**

A real time clock PC BIOS Companion ROM for XT machines supporting many popular RTCs and ISA I/O adapters.

GLaTICK eliminates the need for DOS-based RTC clock drivers/programs letting your supported RTC "just work" like later PCs.

Version 0.8:

Download ROMs

Source Code

Features

• Implements INT 1Ah RTC functionality for seamless clock support. Real time clock is set and read by DOS - no software needed!
• Support for many popular ICs including:
  • DS12x85/MC146818/BQ3285S used by RTC ISA 8 bits/RTC8088 (Buy US/CA,Worldwide), NuXT, Necroware nwX287, Standard AT CMOS (Ports 70h, 240h, 2C0h)
  • MM58167/UM82C8167 used by SixPakPlus V1, Turbo 33-XT, Many clone I/O boards (Ports 2C0h, 240h, 340h)
  • RP5C15 used by SixPakPlus V2
  • MSM5832 used by Quadram, DTK PII-125
  • MSM6242 used by Intel Above Board and other MSM-6242 boards
  • DS1216x/DS1315 SmartWatch "No-Slot" ROM socket clocks
  • MSM/RTC-58321 used by Boca IO/XT22

Requirements

• Any BIOS that supports Option ROMs
• A supported RTC card (of course)
• DOS 3.3 or later **
• GLaTICK ROM image within the valid Option ROM address space. More info here.

Screenshots

SixPakPlus at 2C0h on GLaBIOS:

RTC_8088 on PC/XT:

86Box ISA RTC with local time syncronization:

Build:

Using MASM 5: MAKE GLATICK.MAK.

Using MASM 6: NMAKE GLATICK.NMK.

The included OPT2ROM.COM will convert the produced EXE file to a 2 KiB ROM file.

Roadmap:

• Support for additional RTCs including:
  • Dallas DS1644 Timekeeper

Credits:

• @PickledDog, for the name

Copyright © 2023-25, 640KB and contributors.