[time-nuts] Anyone have info on STel-9270 Universal DDS Interface

[Brian Davis]

Skip Withrow wrote:
 >
 > I have yet to find any information on the STEL-9270.
 >
Questions:
  1) Which STel DDS are you trying to control?
  2) Can you post a link to a picture of the board and cabling?

It's been 20+ years since I last saw one, so a photo might
jog loose a memory cell or two.

As best I recall, these were originally designed to control
the GaAs DDS modules and test fixtures, which used an ECL
interface; but later on they were also used to control some
TTL fixtures, so there might be two interface headers, one
for TTL devices and one for ECL devices.

The DDS interface uses a 50 pin header with frequency[31:0],
phase[1:0], control strobes, and reset.

 >
 > I'm looking for information (specifically the serial commands)
 >
Try the following 8 bit binary escape sequences at 9600,8,N,1:

RESET COMMAND:
  0x1B 0x01

FREQUENCY COMMAND:
  0x1B 0x02 FREQ0 FREQ1 FREQ2 FREQ3

    Where FREQ0 is the LS Byte, and FREQ3 the MS Byte, of FREQ[31:0]

PHASE COMMAND:
  0x1B 0x03 PHASE

    PHASE: the two LS bits of this byte drive test fixture PHASE[1:0]
           0x00    0 degrees
           0x01   90 degrees
           0x02  180 degrees
           0x03  270 degrees

-Brian