PCI bus hard disk activity LED circuit

摘要

A computer system which includes a circuit to monitor the PCI bus master grant lines and provide a disk drive activity signal if an appropriate grant line is activated. The PCI bus master grant lines are combined with mask signals, so that the grant lines not associated with a PCI bus master such as a SCSI controller are ignored. If an unmasked grant line is activated, a down counter is loaded. While the counter is at a non-zero value, a disk drive activity signal is provided. This disk drive activity signal is combined with other disk drive activity signals to drive the disk drive activity LED.