IC-PV Datasheet, PDF (13/28 Pages) IC-Haus GmbH – BATTERY-BUFFERED HALL MULTITURN ENCODER

iC-PV
BATTERY-BUFFERED HALL MULTITURN ENCODER
MODE SELECT INPUT SEL
Rev E2, Page 13/28
The input SEL defines the operating mode of iC-PV.
For the default application as battery buffered multiturn
counter with serial position readout, it is mandatory to
connect the SEL input to GND potential. In case a 3
bit parallel and differential position output is desired, a
high state at SEL input selects the parallel mode. It
is mandatory to connect SEL to a defined high or low
potential.
MODE SELECT INPUT SEL
State
iC-PV Operating Mode
Low
Battery buffered counter with serial readout
High
3 bit parallel complementary output
Open
Not allowed
Table 8: Mode selection via SEL pin
STARTUP BEHAVIOR AND PRESET FUNCTION
The magnetic field is absolutely necessary for startup.
The iC-PV can be booted up in three distinct operating
modes. These are the SSI interface mode, the chain
interface mode and the parallel encoder mode, respec-
tively. In case of a wrong startup procedure, an error is
indicated at pin NERR.
Figure 7 shows the startup procedure of iC-PV. The pro-
cedure starts when a battery supply is available. This
would be the case if a battery is newly attached to the
encoder system or the battery supply is switched on by
an external microcontroller.
insert
battery
send preset pulse via interface pin
SEL = 0 ?
yes
no
VDD ok ?
no
(external supply)
yes
I2C interface active
=> read EEPROM
(max. 3 times on error)
EEPROM ok ?
no
yes
counter preload
Subsequent to powering up the VBAT pin, a preset
pulse (low-high-low) must be applied to the interface
pin (PRE). This resets the internal circuitry to its default
initial state.
Via SEL, the operating mode is selected according to
Table 8. If SEL = high, the chip functions as a 3 bit en-
coder with parallel complementary output and encodes
the current position as shown in Figure 10.
If SEL = low and V(VDD) > V_on during startup, the pre-
set pulse triggers EEPROM readout, therefore VDD
supply has to remain above V_on for at least t_config. The
I²C multi-master tries to readout the configuration data
from an EEPROM connected to SCL and SDA. If the
data can be read without errors, the iC-PV operates in
SSI interface mode or CHAIN interface mode according
to the configuration bit INT_MODE and stays in this
operating mode as long as the battery supply remains
above V_off . After three erroneous attempts, EEPROM
readout is stopped and an error is indicated via NERR
pin.
In parallel encoder mode an external microcontroller
activates the iC-PV in distinct intervals to acquire the
current position. The encoded position is valid when
all complementary bits have changed their logic value
(see Figure 10). After successful position readout, the
battery supply may be switched off. Otherwise, iC-PV
remains in ultra low power idle mode.
Parallel Encoder
Mode Output
Error
Output
INT_MODE ?
0
1
SSI Interface Mode
Chain Interface Mode
Note: A magnetic field according to the specifications
should be provided any time. If a suitable magnetic
target can not be provided during shipment or storage,
please remove the battery.
Figure 7: Startup behavior