'SIMON COMPUTERS Limited' RTC

Simon Time Keeper for Victor/Sirius

As the ACT Sirius 1 / Victor 9000 does not have an RTC (Real Time Clock) fitted the TIME and DATE have to be entered every time the computer is booted up. This can be time consuming and slows down productivity. This could be avoided by installing a RTC clock card to do this job.

The only down side is that ACT Sirius 1 / Victor 9000 has only 4 expansion slots. Should you require more memory these slots are crucial for that memory expansion. A clock card will take a valuable slot limiting further expansion. That said it was a really useful addition to the ACT Sirius 1 / Victor 9000.

The Time Keeper for Sirius/Victor is usable under both MS-DOS and CP/M-86 as there are set up utilities for both operating systems.


Click here to see larger image.

The Simon Time Keeper can be located at one of eight possible addresses in absolute memory, the default address is EBE70H. Should an address conflict arise with another memory mapped device the Simon Time Keeper address can be changed by setting the dip switches on the card.


  Sw1 Sw2 Sw3
EBE70H ON ON ON
EBEF0H OFF ON ON
EBF70H ON OFF ON
EBFF0H OFF OFF ON
EFE70H ON ON OFF
EFEF0H OFF ON OFF
EFFF0H OFF OFF OFF

NOTE: Switch 4 is write protect
ON - to the right --- OFF - to the left


The Time Keeper is based on the MSM5832RS MIcroprocessor, Real-Time Clock/Calandar produced by OKI. It is interfaced to the Sirius via an 8255 PPI (Programmable Peripherial Interface) which is connected to the computer's address and data bus. The card is powered by a 3.6 volt, 100Ma battery.


Last updated: 09/04/2011