**STEREO/HET User's Guide**

**10/22/04**

**Larry Ryan**

This manual is written as a complement to other HET documents already in
existence.

**[PHASIC Channels Used on HET Boards]{.underline}**

  -------------- --------------- ------------- ------------ ------------- ------------ -------------
                 **Engineering                 **Flight                   **Flight     
                 Model**                       Model 1**                  Model 2**    

  **Detector**   **PHASIC**      **Channel**   **PHASIC**   **Channel**   **PHASIC**   **Channel**

  H1i            0               1             0            1             0            1

  H1o            0               11            0            11            0            10

  H2             1               1             1            3             1            2

  H3             1               6             1            5             1            5

  H4             1               8             1            7             1            7

  H5             1               9             1            9             1            10

  H6             1               12            1            12            1            13
  -------------- --------------- ------------- ------------ ------------- ------------ -------------

**[Commands to Run from GSE]{.underline}**

  ------------- -------- ----------- --------- -------- ------------------ ----------------
  **Command**   **PHA    **PHA       **Hex     **\# of  **Description**    **Default in HET
                chip**   channel**   bytes**   bits**                      initial command
                                                                           string**

  phacont       0-1      0-F         x         4        hg-adc-en,         Channels in use
                                                        lg-adc-en,         set to d, all
                                                        verbose, power-on  unused channels
                                                                           set to 0

  tpfbsel       0-1      0-F         xxx       9        test-enable,       H1i, H1o, H2, H6
                                                        testsel3,2,1,0,    set to 6; H3,
                                                        fbsel3,2,1,0       H4, H5 set to C

  inresel       0-1      0-F         xxxx      13       fdgsel2,1,0,       H1i, Hio, H2, H6
                                                        indac9,...,0       set to 1c30; H3,
                                                                           H4, H5 set to
                                                                           1c60

  hgthrsel      0-1      0-F         xxx       10       ioff9,...,0 (for   All channels set
                                                        high gain channel) to provide
                                                                           lowest possible
                                                                           threshold

  lgthrsel      0-1      0-F         xxx       10       ioff9,...,0 (for   All channels set
                                                        low gain channel)  to provide
                                                                           lowest possible
                                                                           threshold

  scopesel      0-1                  xxx       9        scopesel7,...,0,   000
                                                        scope-enable       

  presel        0-1                  xx        5        presel3,2,1,0,     00
                                                        preout-enable      
  ------------- -------- ----------- --------- -------- ------------------ ----------------

'**[phacont' Command]{.underline}**

The 'phacont' command is used like this:

phacont x y z

x = PHASIC \# (0 or 1)

y = channel \# (0 to F)

z = see table below for most common values to use

  ------- ------------------------------------------------------------------
  **z**   **Description**

  0       Turn off channel completely

  1       Disable HG and LG ADC's, but leave channel turned on

  7       Disable HG ADC, enable LG adc

  b       Enable HG ADC, disable LG adc

  d       Enable HG and LG ADCs, verbose mode off (default at boot-up)

  f       Enable HG and LG ADCs, verbose mode on
  ------- ------------------------------------------------------------------

**['tpfbsel' Command]{.underline}**

The 'tpfbsel' command is used like this:

tpfbsel x y z

x = PHASIC \# (0 or 1)

y = channel \# (0 to F)

z = see table below for most common values to use

  ------- ----------------------------------------------------------------
  **z**   **Description**

  6       Disable test pulser, set feedback capacitor to 30pF, and set
          test input capacitor to 0pF (default at boot-up for H1i, H1o,
          H2, H6)

  c       Disable test pulser, set feedback capacitor to 60pF, and set
          test input capacitor to 0pF (default at boot-up for H3, H4, H5)

  166     Enable test pulser, set feedback capacitor to 30pF, and set test
          input capacitor to 18pF

  1cc     Enable test pulser, set feedback capacitor to 60pF, and set test
          input capacitor to 36pF
  ------- ----------------------------------------------------------------

Note that currently the software boots up with the test pulsers disabled
and the test input capacitors set to 0. For flight, you will want the
test pulsers enabled and the test input capacitors set to the same
***hex*** setting as the feedback capacitors (6 for H1i, H1o, H2, H6; c
for H3, H4, H5). Using the same ***hex*** setting for feedback and test
input capacitors allows the test pulser DAC to probe the full dynamic
range of the HG and LG channels. More on that below in the description
of the 'testp' command.

**['inresel' Command]{.underline}**

The 'inresel' command should generally not be used, since the software
automatically sets the indac values (input current DAC to balance
detector leakage current).

**['hgthrsel' and 'lgthrsel' Commands]{.underline}**

These commands will generally not be used, since the thresholds have
been set. The current threshold values are programmed into the software
and will display on the housekeeping page. They should only be changed
(increased) if the noise goes up.

**['scopesel' and 'presel' Commands]{.underline}**

These commands are only useful on the Engineering Model now, and they
are described in Rick Cook's PHASIC document.

**['testp' Command]{.underline}**

The 'testp' command is used to run the on-board test pulser, and its
format is as follows:

testp x y z

x sets the test pulser frequency: freq = 1 / ( x/12500 + 1e-5 ) pulses
per second

(the default at boot-up is currently 4e2 = 10 pulses per second)

y sets the DAC setting for PHA #0 (common test input to H1i and H1o)

z sets the DAC setting for PHA #1 (common test intput to H2, H3, H4, H5,
H6)

(the defaults at boot-up for y and z are 0)

The DAC settings (y and z) can be as follows:

00 to ff (DAC voltages = 0V to .25V)

100 to 1ff (DAC voltages = 0V to 5.00V)

If the test input capacitor and feedback capacitor are set to the same
***hex*** setting (as described above in the 'tpfbsel' command section),
the low range of DAC voltages will stimulate the entire HG channel, and
the high range of DAC voltages will stimulate the entire LG channel.

The test pulser can be run in automatic mode, using this command: testp
auto

This will step through each of the DAC settings (one step per minute) at
the last selected pulser frequency.