MicroE Mercury II 6000 - Manual (Page 31)

Appendix
IM-Mercury_II_6000 Series Rev. 1 Page 30 ©2014 MicroE Systems
Mercury II 6000 Series Encoders
Installation Manual and Reference Guide
7.5 Serial Interface Specifications
Introduction
The serial interface to the Mercury II 6800Si/Pa allows a serial host (controller) to receive position
and status information serially from the sensor. Serial communications between the encoder and
controller permit high speed motion system operation with high encoder resolution: up to 10m/s
with the 1.2nm. The serial data word consists of the following sequence:

Position word of four start bits

Four to thirty-five position bits

Nine bits of status

Six-bit Cyclic Redundancy Check (CRC) to provide error detection

Four stop bits
The encoder’s position is sampled by the MII6800Si at the moment the host commands a sample
(falling edge of nCS); the only latency in the system is the time required for the host to receive the
position word. This architecture minimizes latency and eliminates jitter due to sampling
uncertainty.
Serial Interface Input/Output
MII6800Si (Serial Interface)
Pin Name Direction Description
14 SDATA_OUT+ OUTPUT Serial Data from Sensor to Host
6 SDATA_OUT- OUTPUT Serial Data from Sensor to Host
13 SCLOCK_OUT+ OUTPUT Serial Clock from Sensor to Host
5 SCLOCK_OUT- OUTPUT Serial Clock from Sensor to Host
10 SCLOCK_IN+ INPUT Serial Clock from Host to Sensor
11 SCLOCK_IN- INPUT Serial Clock from Host to Sensor
1 nCS+ INPUT Chip Select from Host to Sensor
3 nCS- INPUT Chip Select from Host to Sensor (Negative True to start capture)
7,8 +5V
2,9 GND
15 Alarm OUTPUT For low level or saturated signal
4 Reserved Do Not Connect
12 Reserved Do Not Connect
MII6800Pa (Panasonic)
The following are the pins used by the MII6800Pa Panasonic serial interface.

Pins 2, 7, 8, 9 are the same for both MII6800Si and Panasonic

Pins 10 and 11 are different for Panasonic

All other pins for Pa are not connected (NC)
Pin Name Direction Description
10 REQ_SD+ Input/Output Request for Serial Data from Host to Sensor
11 REQ_SD- Input/Output Request for Serial Data from Host to Sensor
7,8 +5V Input
2,9 GND Input