HAWAII SAM MICROCODE

Version haw425/6/7.asm

Operation Notes, Version 3, 1 December 1997.

Craig D Mackay.

Changes in this version: The initialisation is now handled without direct reference to the HAWAII devices instead it is done against the reference output. The code has an additional delay built into each frame loop to ensure that the system can run at full speed without producing DMA timeouts. There are now three versions with different ranges of read-out speeds. They are:

haw425.asm 119 to 1090 KHz pixel rate (5 cycles)

haw426.asm 273 to 1500 KHz pixel rate (2 cycles)

haw427.asm 480 to 1714 KHz pixel rate (1 cycle)

This note is a simple users guide to the SAM microcode installed in the 4100 Capella controller and used to drive the Rockwell MCT IR arrays.

1. This version allows HAWAII or PICNIC arrays to be read out in a variety of modes. It contains no VFG type clock pulses so the section of pixcel.ini should look like:

[PDCI]

FrameExtraPixels=0

LineExtraPixels=0

2. All modes use the shutter command to delay the start of read-out by the time shown in the Pixcel "Exposure duration" dialog box. The read-out must be stopped and restarted to reset this (earlier versions of PixCel allowed this to occur on-the-fly). The shutter opening and closing timings are set up for a Vincent Uniblitz 25 mm diameter type only.

3. At the beginning of every FOCUS or SEQUENCE operation the entire device is reset.

  1. The pixel rates are different from those shown in the PixCel dialogue box. This allows the system to cover the optimum read-out rates for the Rockwell devices. The translation to different rates also means that the conversion from data numbers to electrons is also wrong. In order to understand these rates and gain factors the following table should be used for each of the three SAMs with haw425/426/427 (cycles=5/2/10. This table also includes the correct microvolts/electron number for the actual arrays used (rather than the Kodak CCDs that they are intended to refer to. They also refer to the devices run at VD of 1.00 volts rather than 0.50 volts that reduces the gain to 0.54 of the values shown (so increasing the electrons/DN by a factor of 1.84 above the values shown). The Device is then assumed to operate at 6.25 microvolts/electrons.

Haw425.asm (5 cycles per integration period)

Displayed rate Actual rate electrons/DN

KHz KHz multiply by:

500 118 0.34

600 148 0.35

750 197 0.36

1000 292 0.37

1200 387 0.39

1333 463 0.40

1500 571 0.41

1714 755 0.44

2000 and above 1090 0.47

(note intermediate rates all work. Speeds and gain factors may be interpolated)

Haw426.asm (2 cycles per integration period)

Displayed rate Actual rate electrons/DN

KHz KHz multiply by:

500 273 0.85

600 335 0.88

750 428 0.90

1000 600 0.95

1200 752 0.98

1333 862 1.00

1500 1000 1.03

1714 1190 1.10

2000 and above 1500 1.18

(note intermediate rates all work. Speeds and gain factors may be interpolated. There are additional gain reductions as read speed is increased, depending on the bandwidth of the on-chip amplifier)

Haw427.asm (1 cycles per integration period)

Displayed rate Actual rate electrons/DN

KHz KHz multiply by:

500 500 1.70

600 600 1.75

750 750 1.80

1000 923 1.85

1200 1090 1.95

1333 1200 2.00

1500 1333 2.05

1714 1500 2.20

2000 and above 1714 2.35

(note intermediate rates all work. Speeds and gain factors may be interpolated. There are additional gain reductions as read speed is increased, depending on the bandwidth of the on-chip amplifier)

In all modes, sub-array read-out is enabled. Use standard PixCel methods to set a region of interest. Read-out then occurs with that ROI, remembering that the starting X and Y positions and the width and height is accurate modulo 8 only.

The initialisation file pixcel.ini is only loaded into PixCel when it is first run, so if changes are made to pixcel.ini, the PixCel program must be killed and reloaded. Also note that PixCel marks pixcel.ini as "in use" so although your editor might let you think you have just edited it, it may not actually be updated on disk. This can be checked by looking at the USER screen under PixCel. Pixcel.ini contains a section as follows:

[HEAD_CONTROL]

SHUTTER_PULSES=7,7

GROUNDING=FALSE

SHUTTER_TYPE=4

Different values of SHUTTER_TYPE allow different read-out modes to be enabled as follows:

Type 2 The first line of the ROI is read out as you would expect from the

correct row, but subsequent data lines are read out from the same set of

pixels on the device. This is done by omitting the pulse that increments

the row count. Lines are read out until the ROI data set is complete.

One reset is done before the first line is read out but otherwise none are done during this operation.

Type 4 Normal. The entire device or the selected ROI is read out without any

resets.

Type 8 Read-Reset-Read. The selected ROI or the full device is read out as

follows: The start (X,Y) is reached as normal, but only half the

requested pixels are read out in the row. Then that row is reset and the

same pixels are read again. The image recorded is the left hand half of

the selected ROI twice, with the left half of the image before reset, and

the right half after the reset. In order to read out the whole device in

this mode, pixcel.ini needs to be edited as follows:

[CCD_PROPERTIES]

VSPARE_B=128

VSPARE_A=128

CCD_TYPE=Unknown

VABD=64

VABG=64

VOG=89

VRD=71

VOD=163

NO_OF_SEGMENTS=1

CCD_GAIN=1.000

PARALLEL_TIMING=94,22

ACTIVE_AREA=0,0,512,512

CCD_HEIGHT=512

CCD_WIDTH=512

[CCD_READOUT]

BINNING_ENABLE=FALSE

FULL_PARALLEL_BIN=FALSE

FULL_SERIAL_BIN=FALSE

SENSITIVITY=0

PIXEL_RATE=9

REGIONS=0,0,0,512,512

Y_BIN=1

X_BIN=1

The values marked above in BOLD need to be changed to 1024 to allow this mode to function..

Shutter disabled flag This then defaults to Type 4 operation with a reset after each

line is read out. Note that the shutter enable flag is only picked up

with a stop/start operation, and cannot be picked up on the fly in the

version of PixCel used for these tests.

Different initialisation files. There are a number of initialisation files (*.ini) files available. The names tell all about their contents. All are made up of:

hawxcyqzm.ini where:

haw (HAWAII CHIP) xc (x=1-4 HAWAII detectors or chips) yq (y=1-4 quadrants) zm (z-2,4 or 8 mode). If the chip selected under "1c" is not chip 1, then 1c(x) is the format.




CDM.