Patent ID: 7787766

Claim:
A fault sensing apparatus in an integrated circuit for connecting to a laser module in a host system, comprising: a laser driving circuit ( 20 ) including a plurality of checkpoints, each checkpoint connected to a fault sensor for monitoring a plurality of operating faults in the laser module, wherein each checkpoint performs a comparison with a reference level and outputs a fault signal ( 22 ) based on the comparison; a status bit register for separately storing each of the fault signals to enable identification of each operating fault independently; a logic block between the checkpoints and the status bit register for receiving the fault signals and outputting alarm signals to the status bit register; a SPI core register bank including the status big register disposed to provide control signals to the logic block for connecting a selection of the fault signals to the alarm signals; a first fault state register in the SPI core register bank for controlling alarm signal acquisition; wherein the first fault state register is disposed to disable the logic block from outputting any subsequent alarm signals after a first occurrence of a fault signal has been detected.