IC-LNB_16 Datasheet, PDF (18/37 Pages) IC-Haus GmbH – 18-BIT OPTO ENCODER

iC-LNB 18-BIT OPTO ENCODER ^preliminary
WITH SPI AND SER/PAR INTERFACES
Reset values
After power-on the registers are initialized as follows:
Address
0x00-0x01
Reset
Value
0xA0
0x02-0x05 0xC0
0x06
0x60
0x07
0x09
0x08
0x18
0x09-0x0A 0x00
0x0B
0x8E
0x0C-0x10 0x00
0x11
0xA0
Description
Gain (GS, GC) = 1.408
LED control behaivor (LCMOD) = 0
Offset (OSP, OSN, OCP, OCN) =
0.5004*VDDA
LED control mode (LCTYP) = sum
control, Set point (LCSET) = 0.23 V
Shift register output format (NGRAY) =
GRAY,
Direction (DIR) = CW,
EPG = interface mode,
Oscillator (OSZC) = 14.4MHz,
Gain range (GR) = 1.33
Interpolator factor (INC) = x2,
Idle state DOUT (RNF) = ’1’,
Shift register (SRC) = 18 bit
Test functions = 0,
Hysteresis (HYS) = 0°
ABZ outputs (INVA/B/Z) = not inverted,
ABZ outputs (TRIABZ) = tri-state, Shift
register (SELABS) = max. resolution,
FlexCount (NENFLEX) = disabled
FlexCount parameters = 0
FlexCount:
Outputs (NOUTLO) = low,
Reset (STOPFLEX) = stopped,
Interpolator (ENIPO) = disabled
Table 7: Register reset values (RAM)
Rev B2, Page 18/37
Programming sequence
Following iC-LNB’s system reset (POK lo → hi) the
internal RAM must be configured to through the SPI in-
terface. A microcontroller with an integrated EEPROM
and SPI master is usually used for this purpose. De-
pending on the required function the parameters must
be written in a certain order (Figure 4).
If iC-LNB is to be used without FlexCount, only the
required interpolator resolution is set (RESIPO) and
enabled (ENIPO). The drivers at the A/B/Z outputs are
then switched from tristate to push-pull state.
If the device is to be operated with FlexCount, the user
then decides whether to leave the A/B/Z outputs in low
or switch these to tristate (TRIABZ). After configuring all
parameters, FlexCount is enabled (STOPFLEX 1 → 0).
After the current position has been found (POSOK), the
A/B/Z outputs can be enabled (TRIABZ or NOUTLO).
NB: In order to avoid infinite loops e.g. in case
of glitches or communication errors, the query for
POSOK should be aborted after a defined waiting pe-
riod of 30 ms (up to 1000 RPM) to initiate a restart
(cue defensive programming for safety requirements).
After e. g. 5 restarts a configuration error should be
reported.