System information

Special Control Register
VSBC-6 Reference Manual Reference – 55
Special Control Register
SCR (READ/WRITE) 00E0h (or 01E0h via CMOS Setup)
D7 D6 D5 D4 D3 D2 D1 D0
LED Reserved REV Reserved COM1DIS COM2DIS ETHDIS WDOGEN
Table 31: Special Control Register Bit Assignments
Bit Mnemonic Description
D7 LED Light Emitting Diode — Controls the programmable LED connector J7
LED = 0 Turns LED off.
LED = 1 Turns LED on.
D6 — Reserved — This bit has no function. Always reads as 1.
D5 REV Rev Indicator — Indicates the board revision level. The system BIOS reads this
bit to determine SDRAM support.
REV = 0 Board revision 3.02 and earlier.
REV = 1 Board revision 4.00 and above.
Note! This bit is a read-only bit.
D4 — Reserved — This bit has no function. Always reads as 1.
D3 COM1DIS COM1 Disable — Enables and disables COM1.
COM1DIS = 0 Enables COM1.
COM1DIS = 1 Disables COM1.
D2 COM2DIS COM2 Disable — Enables and disables COM2.
COM2DIS = 0 Enables COM2.
COM2DIS = 1 Disables COM2.
D1 ETHDIS Ethernet Disable — Enables and disables the Ethernet port.
ETHDIS = 0 Enables Ethernet port.
ETHDIS = 1 Disables Ethernet port.
D0 WDOGEN Watchdog Enable — Enables and disables the watchdog timer reset circuit.
WDOGEN = 0 Disables the watchdog timer.
WDOGEN = 1 Enables the watchdog timer.