IC-MHM Datasheet, PDF (38/63 Pages) IC-Haus GmbH – 14-BIT ABSOLUTE ANGLE HALL ENCODER

iC-MHM
14-BIT ABSOLUTE ANGLE HALL ENCODER
in the multiturn count field and the unused MSBs are ^LC
set to zero.
Code
0x00
0x01
For example, if RESO_MT = 5, the multiturn count is
a 20-bit value in a 24-bit field. In this case, bits 19:0 ^...
contain the multiturn count while bits 23:20 are zero. ^0x3F
Refer to MULTITURN INTERFACE on page 23 for more
information on RESO_MT.
Rev D1, Page 38/63
Value
Initial value after power-on, reset and preset
Value on first request for new position data
and follow-up value on the maximum
...
Max. value
Table 66: Sign-of-life counter
The singleturn position bit length depends on the inter-
polator resolution as set by parameter RESO_ST, but is
always fixed at 12 or 16 bits. If the singleturn resolution
(in bits) is less than one of these values, 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 12-bit field. In this case,
bits 11:2 contain the singleturn position while bits 1:0
are zero. Refer to INTERPOLATOR on page 21 for
more information on RESO_ST.
The active-low BiSS error bit, nERR, is activated when
any of the error bits in the error status register is active.
Refer to STATUS REGISTERS on page 30 for more
information.
The active-low BiSS warning bit, nWARN, is activated if
magnet rotation speed is excessive. Refer to INTERPO-
LATOR on page 21 for more information on maximum
rotation speeds.
In safety applications, a sign-of-life counter (life counter)
value can be transmitted after the BiSS warning bit in
the SCD.
The count value is incremented after each new BiSS
cycle. If the sign-of-life counter is disabled (ENLC = 0),
no additional bits are transmitted and the CRC code
immediately follows the nWARN bit in the SCD.
The Cyclic Redundancy Check value (CRC) is trans-
mitted in its inverted state last in the SCD. If the
sign-of-life counter is disabled (ENLC = 0) a 6-bit CRC
code is transmitted; if the sign-of-life counter is enabled
(ENLC = 1), a 16-bit CRC value is transmitted.
The starting value of the checksum calculation is de-
termined by CRCS. The CRC is calculated using the
selected CRC start value and the polynomial shown in
Table 65 based on ENLC.
CRCS
Value
0x00
0x01 ...
0x3F
Address 0x0A; bits 5:0
Function
Default CRC Start Value (BiSS Encoder Profile
BP1 and BP3)
Unique CRC Start Value Used By All Slaves
on the BiSS Channel
Table 67: CRC Start Value
Adaptive Timeout
The iC-MHM can provide a fixed or adaptive BiSS time-
out depending on the setting of parameter NTOA. For
fastest communication speed, it is recommended to
use the adaptive timeout.
ENLC
Value
0
1
Address 0x0A; bit 6
CRC HEX
Code
Description
0x43
Sign-of-Life Counter Disabled.
CRC Polynomial: X⁶ + X¹ + X⁰
0x190D9
16-Bit Sign-of-Life Counter Value.
CRC Polynomial:
X¹⁶ +X¹⁵ +X¹² +X⁷ +X⁶ +X⁴ +X³ + X⁰
Table 65: Sign-of-Life Counter Enable
NTOA
Value
0
1
Address 0x07; bit 6
Description
Adaptive Timeout
Fixed Timeout
Table 68: Adaptive Timeout
If NTOA = 1, a fixed nominal timeout of 20 µs (with a
14 MHz system clock) is used (refer to Elec. Char. item
no. 501 and 904).
If the sign-of-life counter is enabled (ENLC = 1), a 6-bit
count value (0 - 63) is transmitted last in the SCD. Its
reset value of zero is never output as it is bypassed
during normal operation.
If NTOA = 0, the iC-MHM adapts the BiSS timeout
length based on the period of the BiSS MA clock, T_MA,
and its internal sampling frequency, 1/T_CLK, to ensure
fastest communication. In operation, the iC-MHM mea-
sures 1.5 periods of MA (from the first falling to the