IC-LNB_16 Datasheet, PDF (30/37 Pages) IC-Haus GmbH – 18-BIT OPTO ENCODER

iC-LNB 18-BIT OPTO ENCODER ^preliminary
WITH SPI AND SER/PAR INTERFACES
Rev B2, Page 30/37
The FlexCount output signals can be set to low us-
ing register bit NOUTLO; FlexCount itself continues to
run. This function should be used after FlexCount has
been reset to prevent the device ’running’ to the current
position in the output signals.
NOUTLO
Code
0
1
Addr. 0x11; bit 6
Internal FlexCount outputs
low
Normal operation
Table 35: Setting FlexCount outputs to low
Hysteresis
A hysteresis can be programmed for FlexCount. The
size of the hysteresis can be set as a multiple of the
interpolator LSB step size using parameter HYS. This
means that the resolution of the interpolator influences
the selectable hysteresis.
INVZ
Code
0
1
Addr. 0x0B; bit 4
Incremental output INCZ
not inverted
inverted
Table 39: Output inversion INCZ
Position offset
iC-LNB’s FlexCount permits a programmable position
offset. This offset can be set as a binary value of the
maximum internal resolution (which is dependent on
interpolator resolution RESIPO) using parameter ZPOS
(not in the selected FlexCount resolution). All values
from 0 to 262,143 can be selected at 8 bits; at 7 bits
the LSB must remained fixed at 0, and at 6 bits the last
two LSBs must be 0. If no position offset is set (ZPOS =
0x0), the zero position is symmetrical with the falling
edge of the MSB (in interface operation: signal at pin
GA, Figure 19).
HYS
Code
0x0
0x1
0x2
0x3
0x4
...
0xFC
Addr. 0x0B, bit 0; Addr. 0x0A, bit 6:0
RESIPO = 0x0 RESIPO = 0x1 RESIPO = 0x2
8-bit interp. 7-bit interp. 6-bit interp.
No hysteresis No hysteresis No hysteresis
±1 LSB
No hysteresis No hysteresis
±2 LSB
±1 LSB
No hysteresis
±3 LSB
±1 LSB
No hysteresis
±4 LSB
±2 LSB
±1 LSB
±252 LSB
±126 LSB
±63 LSB
Table 36: FlexCount hysteresis
Incremental outputs
When FlexCount is enabled, incremental outputs A/B/Z
can be inverted as required using register bits INVA,
INVB, and INVZ. If the A/B/Z outputs are not generated
by FlexCount (INC ̸= 0x07), inversion will not function.
INVA
Code
0
1
Addr. 0x0B; bit 6
Incremental output INCA
not inverted
inverted
Table 37: Output inversion INCA
GA (MSB)
INCZ
INCA
INCB
ZPOS = 0x0
Figure 19: Zero position for ZPOS = 0x0
ZPOS
Code
0x0
0x1
0x2
...
0x7FFF
...
0x10000
...
0x3FFFF
Addr. 0x0C; 0x0D; 0x0E bit 3:0
Positions offset (binary)
0
1 (only with 8 bit interpolation)
2 (only with 7/8 bit interpolation)
ZPOS
32767 (only with 8 bit interpolation)
ZPOS
65536
ZPOS
262143 (only with 8 bit interpolation)
Table 40: Position offset
The length of the Z pulse can be selected using pa-
rameter Z90. It can be set to a width of 90^◦ or 180^◦
.
INVB
Code
0
1
Adr 0x0B, bit 5
Incremental output INCB
not inverted
inverted
Table 38: Output inversion INCB
Z90
Code
0
1
Addr. 0x0E; bit 4
Index width
180^◦
90^◦
Index gating
A
A&B
Table 41: Z pulse width