B&B Electronics PCRTC manual Operation, Overview, Using the Device Driver

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Chapter 3. Operation

Overview

The most common application of the PCRTC is to simply maintain the correct time on the host computer. Loading the device driver in the CONFIG.SYS file will accomplish this function by setting the DOS clock to the PCRTC clock time once every minute. This allows the user and all applications access to the correct time without any special commands or function calls.

The PCRTC has two additional features which may either be incorporated using the provided “include file” and making function calls within your program, or from the command line using the PCRTC.EXE file. The first of these functions is battery status. By checking the battery status you can take action on a low battery before the time is corrupted. The second function is the time of last power loss or reset. By checking this function, the time of the last host computer power loss or system reset can be determined.

Using the Device Driver

In order for the PCRTC to automatically update the DOS clock, the device driver PCRTCDD.SYS must be loaded from CONFIG.SYS. This is done automatically by the installation program. The following line will be added to the CONFIG.SYS file:

DEVICE = {path}PCRTCDD.SYS /A:{hex PCRTC address}

For example, if the file PCRTCDD.SYS is in the directory C:\PCRTC, and the card address is set to 200h, use the following line.

DEVICE = C:\PCRTC\PCRTCDD.SYS /A:200

If the address 200 is not compatible with your hardware, the address parameter must be changed to match the address that was selected for the hardware. After modifying the CONFIG.SYS file, reboot the host computer. If the hardware and driver are installed correctly, you should see the following message during bootup.

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Documentation Number PCRTC2095 Manual

B&B Electronics --

PO Box 1040 -- Ottawa, IL 61350

PH (815) 433-5100 -- FAX (815) 433-5105

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Contents Electronics Mfg. Co. Inc Designed and Manufactured Ottawa, IllinoisInternet Table of Contents Introduction SpecificationsGeneral Information Packing ListSetup Hardware SetupHardware Installation Software SetupUsing the Device Driver OperationOverview Command Line Options Setting the Pcrtc Time and DateReplacing the battery Programming with the PcrtcBatteryRTC StartRTCAPIGetRTCTime WordLastPowerDownRTC QuickBASIC Example Pascal Programming ExampleProgramming Example Calculating Error Oscillator ErrorPPM Terminology Aging Appendix A. Hardware I/O Map Map of XT Class MachinesHardware I/O Map of AT Class Machines