Avago AEAT-6600-T16 rotary encoder (magnetic) implementation with SSI on Uno?

Good day forum,

I would appreciate it if someone could assist me with the following.

I am using (trying) a Avago AEAT-6600-T16 rotary encoder with an Uno to determine the absolute angle of a shaft that rotates only once a day, but the angle is very important. I’ve never worked with bit shifting before and have found a link on the forum (http://forum.arduino.cc/index.php?topic=156812.0) where “johnwasser” posted some code to get the data from a SSI sensor. I only changed the “BIT_COUNT” to 10 in the code as that is the default on the chip. I’ve not programmed the chip and connected it according to the diagram shown in the Avago Application notes, figure 10 on page 9.

When running the code and viewing the output on the serial monitor I only see the text “Reading: 1023” continuously. I’ve noted that the output changes to “Reading: 0” when I rotate the magnet in a CW direction and back to “Reading: 1023” when turning it CCW. Unfortunately, that is all I get.

Any ideas on how I can “debug” this or determine if the chip is working correctly?

Thanks in advance.

AV02-2791EN_AN_5501_AEAT-6600_2014-04-21%2C0.pdf (488 KB)

The 0 Ohm "resistors" in that drawing are misleading. These indicate jumpers or DIP switches, which you open or close to select exactly one of the available signals for each line. Remove all excess shorts, connect only the SSI related pins directly to the Arduino.

For an first test you can output the individual received bits, via Serial.print, followed by your converted number.

Thank you for the response DrDiettrich.

I’ve changed the circuit as per my interpretation of your response and this is shown in the attachment. I do however still get the same output with the sketch from “johnwasser”.

I’ve also tried the attached sketch from “MadScientist” (www.MadScientistHut.com/forum_php) and I also get the same results {1023 and 0}. I’ve un-commented some of the serial.print statements to view what is happening, but no change in data read.

In this layout, what could prohibit the chip from giving a different output when the magnet is rotated?

Avago AEAT-6600-T16 Circuit.pdf (408 KB)

SSI_EncoderMad.ino (4.3 KB)

SSI_EncoderMad.ino (4.3 KB)