IC-MHM Datasheet, PDF (44/63 Pages) IC-Haus GmbH – 14-BIT ABSOLUTE ANGLE HALL ENCODER

iC-MHM
14-BIT ABSOLUTE ANGLE HALL ENCODER
Rev D1, Page 44/63
EXT_SSI
Value
0
1
Address 0x03; bit 6
Protocol
Standard SSI Protocol
Extended SSI Protocol
Table 84: SSI Protocol
Standard SSI protocol transmits only multiturn count
and singleturn position. In addition, the singleturn reso-
lution is limited to 13 bits or less.
Extended SSI protocol transmits multiturn count, single-
turn position at any resolution, error and warning bits,
and an optional sign-of-life counter value.
Standard SSI Protocol
Standard SSI protocol (ENSSI = 1 and EXT_SSI = 0)
provides selectable multiturn bit lengths and fixed 13-bit
singleturn bit length.
MA
SLO
...
MT(11:0)
...
Frame
Cycle
ST(12:0)
Timeout
STOP
Idle
Figure 25: Standard SSI Protocol
The multiturn count (MT) is transmitted first, followed
by the 13-bit singleturn position (ST) and a timeout. All
values are transmitted MSB first in the order shown in
Table 85.
Standard SSI Protocol Frame
Bit Length Description
0 - 32
Multiturn Position (Turns Count - OFFS_MT)
13
Singleturn Position (Magnet Angle - OFFS_ST)
Table 85: Standard SSI Protocol Frame
The singleturn bit length is fixed at 13, but the singleturn
resolution depends on the interpolator resolution as set
by parameter RESO_ST. If the singleturn resolution (in
bits) is less than 13, the singleturn position value is left-
-justified in the singleturn position field and the unused
LSBs are set to zero.
For example, if RESO_ST = 6, the singleturn position
(angle) is a 10-bit value in a 13-bit field. In this case,
bits 12:3 contain the singleturn position while bits 2:0
are zero.
Refer to POSITION OFFSET AND PRESET (Zero Po-
sition) on page 55 for more information on the position
offset parameters OFFS_MT and OFFS_ST.
Singleturn resolutions greater than 13 bits
(RESO_ST < 3) may not be used in standard SSI mode.
Refer to INTERPOLATOR on page 21 for more infor-
mation on RESO_ST.
A constant high level on SLO indicates that one or
more of the error bits in the error status register is ac-
tive. Refer to STATUS REGISTERS on page 30 for
more information.
Extended SSI Protocol
Extended SSI protocol (ENSSI = 1 and EXT_SSI =
1) provides selectable multiturn bit length, selectable
singleturn bit length, error and warning bits, and an
optional sign-of-life counter value.
Figure 26: Extended SSI Protocol
The multiturn count (MT) is transmitted first, followed bit, and an optional sign-of-life counter value. All values
by the singleturn position (ST), an error bit, a warning