Skip to content

Latest commit

 

History

History
46 lines (34 loc) · 2.45 KB

RTC.md

File metadata and controls

46 lines (34 loc) · 2.45 KB
Raw

Real-Time-Clock (RTC) for GEOS

The MEGA65's Real Time Clock (RTC) is able to power the date/time in GEOS.

How to use the RTC in GEOS

  1. Optional: Learn how to use GEOS using C64 for MEGA65
  2. Use the MEGA65's "Configuration Utility" to set the correct date and time. Learn more in the MEGA65 User's Guide chapter "The Configuration Utility".
  3. Download the GEOS RTC driver here.
  4. Use a tool like DirMaster to extract the driver CP-CLOCK-1.3.PRG from the .D64 file and to add it to your personal GEOS boot disk, which might for example be called GEOS64.D64.

Differences between pre-2024 MEGA65s and 2024+ MEGA65s

  • If you have a MEGA65 that has been built in 2024 or later, then you are all set.
  • If you have a pre-2024 MEGA65 model, then you need to install a CR1220 battery as described in the "MEGA65 User's Guide", otherwise the RTC will "forget" the date/time each time you power-off your machine. Here are instructions how to install the battery.
  • A minority of pre-2024 MEGA65 are having a damaged RTCs. Here is an article that describes how to request a replacement from the MEGA65 team and how to install it. However, the C64 for MEGA65 core is not yet supporting the replacement RTC.
  • Learn more details about the different MEGA65 models here.

Background and History: CP-Uhr F83 by Jörg Sproß

From a technical perspective, we are simulating the "CP-Uhr F83" by Jörg Sproß which uses a PCF8583 chip that is connected via the tape port. Here are some resources about the background and history of this clock (most of them in German only):

And here is an image how the original device looked like:

CP-Uhr