Trying to solve the vertical clocking problem (Feb 4-7, 2005) Test conditions 277 kHz clock – instead of the 100 kHz recommended V_reset = 1V V_bias_gate = 2.4 V V_bias_power = 3.3 V Vtesten, Htesten = 0 – a 1 enables frame and line checks Formats: main x 1024 tried 2048 x 2048 also 512 x 512

IR Single & CDS (1024 x 1024) Used hot & dead columns as well as image features to identify the quadrants sampled in each frame IR Single 3 of 4 frames were of lower left quadrant (the one closest to origin) 1 of 4 frames was of the upper left quadrant (1025 < y < 2048) CDS Every fourth frame cycle also exists here, but hard to determine orientation since

IR Single Frames (2048 x 2048) Vertical 1 st frame bottom – none Top -- 9 pixels 2 nd & 3 rd frames bottom -- 5 pixels Top – 4 pixels 4 th frame appears to be a difference frame – can’t identify ref pixels Vertical 1 st frame bottom – none Top -- 9 pixels 2 nd & 3 rd frames bottom -- 5 pixels Top – 4 pixels 4 th frame appears to be a difference frame – can’t identify ref pixels Horizontal 4-pixel borders on left and right for images 1-3 can’t tell if it exists for 4 th image  Horizontal clocking is okay Folder: Feb4 Filenames: IRS_2048_ fits

IR Single Frames (2048 x 2048) Turned on the reference pixel row to see if we can use it to distinguish start of frame REFMODE = 0, meaning that reference pixels are reset as with other pixels (instead of reset being during the entire read cycle) Now the frame has a streak pattern repeating every 4 th column  Don’t understand why reference row alters the readings on all other pixels Turned on the reference pixel row to see if we can use it to distinguish start of frame REFMODE = 0, meaning that reference pixels are reset as with other pixels (instead of reset being during the entire read cycle) Now the frame has a streak pattern repeating every 4 th column  Don’t understand why reference row alters the readings on all other pixels Folder: Feb4 Filename: IRS_2048_0021.fits

CDS Frames (2048 x 2048) Only frames 2 and 6 look anything like CDS differences. Other frames might as well be IRSingle. Note that the reference pixel row is still enabled, causing vertical streaks, and perhaps the gradients in frames 2 and 6. Only frames 2 and 6 look anything like CDS differences. Other frames might as well be IRSingle. Note that the reference pixel row is still enabled, causing vertical streaks, and perhaps the gradients in frames 2 and Folder: Feb4 Filenames: CDS_2048_ fits

Vertical clocking is problematic Can’t seem to generate LINECHK or FRAMECHK pulses, even after adding extra overclocking pulse for VCLK in idle-mode and read array assembly subroutines FSYNCB VCLK LINECHK (same response for FRAMECHK) HCLK Should have been a pulse here for LINECHK & FRAMECHK, but seee NONE for either signal, even though internal & external settings for VTESTEN & HTESTEN are set high <  Adding an overclock to VCLK still doesn’t give FRAMECHK signal (change made to idle assembly routine)

Things are okay in the horizontal direction Two pre-charge pulses in HCLK give rise to three integrator pulses ? Why ? However, horizontal clocking is okay in both IRSingle & CDS images, so this is not a real problem HCLK Integ_out Integ_in Mux_out conv Falling edge of HCLK clocks in new pix