iC-LNB 18-BIT OPTO ENCODER
WITH SPI AND SER/PAR INTERFACES
Rev A1, Page 21/35
REQ
PACTIVE
CS
SCLK
MOSI
MISO
Code
Description
0
1
Sensor data channel deactivated
Sensor data channel activated
OP
Table 12: Sensor data activation
OP
SD1
SD2
SD3
8 cycles
If PACTIVE is not set, on commands Sensor data sta-
tus or Sensor data transmission the ERROR bit is
set in the STATUS byte (Table 14), indicating that the
command has not been carried out. The slave imme-
diately outputs the data at MISO which has been sent
by the master through MOSI.
Figure 8: SDAD transmission: read SD
With command Sensor data transmission the master
can not only read sensor data (SD) out from the slave;
at the same time it can also transmit actuator data (AD)
to the slave. iC-LNB ignores the transmitted actuator
data.
If only one slave is connected up with one register and
one sensor data channel, it must be ensured that the
RACTIVE and PACTIVE bits are last in the data byte
(Figure 7).
REQ
CS
SCLK
NB: daisy chain
OP
OP
AD1
SD1
AD2
SD2
AD3
SD3
MOSI
MISO
If the slaves are connected in a chain (full duplex
chain), with this command the master can determine
the number of connected register and sensor data
channels. To this end it can send a 1 after the OP-
CODE, which is repeated at MISO after the number
of register and sensor data channels (see Figure 7).
8 cycles
Figure 9: SDAD transmission: read SD, write AD
Sensor data status
CS
Should the master not know the processing time, it can
request sensor data using the command Sensor data
status. iC-LNB does not need any processing time;
therefore, SVALID is always valid.
SCLK
1
0
0
0
0
1
0
0
0
0
0
0
RA PA
OP
OP
MOSI
MISO
0
0
The command causes
8 cycles
RACTIVE / PACTIVE vector
1. all slaves activated with PACTIVE to switch their
SVALID register between MOSI and MISO.
Figure 7: Setting ACTIVATE: RACTIVE/PACTIVE
(one slave)
2. The next request for sensor data, triggered on
the first rising edge at SCLK when CS has again
been set to 1, is ignored by the slave.
Sensor data transmission
iC-LNB latches its position data on the first rising edge
at SCLK if CS is switched to 1 (REQ). The sensor data
shift register is switched between signals MOSI and
MISO for SPI communication and can then be clocked
out. The size of the sensor data shift register must
be set to 18 bits (see section on shift register output,
page 30). The position data is output with the MSB
first. Byte SD3 (Figure 8) is then filled with zeroes.
The end of conversion is signaled by SVALID (SV).
With this command the master can poll to the end of
conversion. The sensor data is readout on the com-
mand SDAD transmission.
SVALID
Code
Description
0
1
Sensor data channel invalid
Sensor data channel valid
If invalid data is sampled in the shift register, the
ERROR bit is set in the STATUS byte (Tab. 14) and
zeroes are output as the data word.
Table 13: Sensor data valid indication
ICHAUS [ IC-HAUS GMBH ]
