Log of Problems and Solutions

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SOLVED 2-8-2012 Jitter and Flashing of 1st column in 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.

SOLVED 6-1-2012 Buffer chips could get more than 5V

PROBLEM: It was possible through software to apply more than 5V to the buffer chips. This allows developers and users to issue a "Self-Destruct" command. This has been tested out and verified to work. (Too soon to joke?)

SOLUTION: Initially there was a Software fix, but a hardware solution was implemented and was included in the final 12 boards.

NOT SOLVED YET

Noise and gain not as good as we would like on the prototypes with the buffer chips.