Real Time Clock for your PC XT. Very low profile, simple and open hardware.
I/O Address | SW1.1 | SW 1.2 | SW 1.3 |
---|---|---|---|
0x70 | OFF | OFF | OFF |
0x240 | ON | OFF | OFF |
0x2A0 | OFF | ON | OFF |
0x2C0 | ON | ON | OFF |
0x340 | OFF | OFF | ON |
0x3A0 | ON | OFF | ON |
0x3C0 | OFF | ON | ON |
Reserved | ON | ON | ON |
Position | Description | ||
open (default) | Normal operation | ||
closed | Clear NVRAM memory |
It is a project based on the SMBacker RTC but without Disk On Chip memory and a very low profile.
If your PC BIOS does not have support for RTC, you must use its management software, there are already several solutions for this purpose. However, after several tries it has been observed that these do not work properly. I suggest the use of the this application programmed by Alejandro Valero that has shown adequate operation:
COMMANDS (Default port 2C0h)
SETRTC.EXE - Update RTC from system date/time
GETRTC.EXE - Update system date/time from RTC
BATRTC.EXE - Check RTC battery status
All the commands allow a parameter with the port number that we want to use in decimal. So, to use it on port 240h, you must indicate parameter 576…
The best thing is that once you have it configured, add "get_RTC" to the autoexec.bat.
Testet, works. Private Selling, so no warranty.