IC-MHM Datasheet, PDF (57/63 Pages) IC-Haus GmbH – 14-BIT ABSOLUTE ANGLE HALL ENCODER

iC-MHM
14-BIT ABSOLUTE ANGLE HALL ENCODER
STARTUP AND OPERATION
Startup
As shown in red in Figure 43, after power on, the
iC-MHM attempts to read the configuration and offset
data from an external EEPROM via the I²C multi-master
interface. During this period, the error output is active
(NERR = 0) and SLO is driven high to indicate that se-
rial port communication is not possible. If a properly
configured EEPROM is present, the EEPROM data is
read into RAM and two CRCs are done to verify the
configuration and offset data.
If no EEPROM is present or a CRC fails, two more
attempts to read the EEPROM are made. After the third
failed attempt, the iC-MHM goes into an idle state with
the error output activated (NERR = 0) and SLO driven
high to indicate the error. In this case, the iC-MHM
must be configured or re-configured as explained in
CONFIGURATION on page 52.
If the CRCs pass, the configuration and offset data are
valid and SLO is released, allowing communication via
the serial port.
Startup proceeds as shown in yellow in Figure 43. First,
the automatic amplitude control is started if enabled
(ENAC = 1) and the singleturn position (magnet angle)
is calculated. Then, if the multiturn interface is enabled
(SBL_MTI > 0), the multiturn data is read from the exter-
nal multiturn sensor and synchronized with the single-
turn data. This process repeats indefinitely if a multiturn
error occurs. Refer to MULTITURN INTERFACE on
page 23 for more information.
During this phase of startup, absolute position is not
yet available. If requested, a zero value is returned. In
addition, the error and warning bits in the BiSS SCD,
SPI position read command response, and extended
SSI frame are active (nERR = nWARN = nE = nW = 0).
If there are no errors, the error output is de-activated
(NERR = 1), the error and warning bits in the BiSS SCD,
SPI position read command response, and extended
SSI frame are de-activated (nERR = nWARN = nE =
nW = 1), and the iC-MHM is ready for normal operation.
Refer to STATUS REGISTERS on page 30 for more
information on errors.
Rev D1, Page 57/63
Figure 43: State Diagram