Log of Problems and Solutions

2-8-2012 Jitter and Flashing of image

PROBLEM: On front illuminated image it was observed that the images had a flashing on the first column and that there was a pixel jitter.

CAUSE: The pipeline in the fCRIC must first be purge before we get the real data from the CCD. This is done in state 4 of the readout state machine. After state 4 the readot goes to state 5 where it starts saving data. The state machine was entering state 5 while in the middle of the data transfers started in state 4.

SOLUTION: Extend the end time of state 4 from 96 ticks to 245 ticks. This will prevent the system from entering state 5 until the fCRICs are done sending out their data. Since this state is only used for 6 pixles it will not have a signifigant inpact on the total readout time.