
preliminary
preliminary
iC-PVS
LINEAR/OFF-AXIS
BATTERY-BUFFERED ABSOLUTE POSITION HALL SENSOR
Rev A2, Page 43/51
Activate Slave In Chain
RAPA
Byte 1
8 cycles
SCLK
MOSI
MISO
NCS
OP
OP
*
Figure 30: Activate Slave in Chain command with 1
RAPA Byte
* Data content is defined by the shift register output
Each SPI slave provides separate channels for register
and sensor data transfer that can be switched on and
off individually. Register communication with iC-PVS is
only possible if RACTIVE = 1. Otherwise register com-
munication attempts are ignored. Sensor data (position
data) can only be acquired from iC-PVS if PACTIVE =
1. Otherwise opcode Read Position (0xA6) is ignored.
By sending opcode Activate Slave In Chain (0xB0) each
iC-PVS acts as a 2-bit shift register containing one RAC-
TIVE and one PACTIVE configuration bit. The RAC-
TIVE and PACTIVE bits are initialized as ’0’, turning
both data channels off. The SPI Status Byte is reset.
Following the opcode, the desired RACTIVE/PACTIVE
channel configuration is transmitted. Data bytes cor-
responding to all possible configurations are shown in
Table 57. Slave number 0 is considered to be the last
slave in in chain directly connected to MISO of the SPI
master.
RACTIVE
default: 1
Code
Description
0
Register communication deactivated
1
Register communication activated
Table 55: RACTIVE (RA)
PACTIVE
default: 1
Code
Description
0
Sensor data channel deactivated
1
Sensor data channel activated
Table 56: PACTIVE (PA)
iC-PVS(1)
MOSI
MISO
Master
MOSI
MISO
iC-PVS(0)
MOSI
MISO
PA1 RA1
PA0 RA0
Figure 31: SPI slaves after sending the Activate
Slave In Chain command
Slaves OPCODE
RA/PA configuration byte 0
RA/PA configuration byte 1
2
0xB0
0
0
0
0
RA0 PA0 RA1 PA1
Not used
3
0xB0
0
0
RA0
PA
RA1 PA1 RA2 PA2
Not used
4
0xB0
RA0 PA0 RA1 PA1 RA2 PA2 RA3 PA3
Not used
5
0xB0
0
0
0
0
0
0
RA0 PA0 RA1 PA1 RA2 PA2 RA3 PA3 RA4 PA4
6
0xB0
0
0
0
0
RA0 PA0 RA1 PA1 RA2 PA2 RA3 PA3 RA4 PA4 RA5 PA5
7
0xB0
0
0
RA0 PA0 RA1 PA1 RA2 PA2 RA3 PA3 RA4 PA4 RA5 PA5 RA6 PA6
8
0xB0
RA0 PA0 RA1 PA1 RA2 PA2 RA3 PA3 RA4 PA4 RA5 PA5 RA6 PA6 RA7 PA7
Table 57: RA/PA channel configuration bits for 2-8 slaves
Note:
Reading the state of
and
is not possible.
Only one register data channel (RACTIVE) in the SPI
daisy chain may be active at a time. All sensor data
channels (PACTIVE) in the SPI daisy chain may be ac-
tive simultaneously. Figure 32 shows the data scheme
when reading sensor data in a SPI daisy chain.
SD Slave 0
8 cycles
SCLK
MOSI
MISO
NCS
OP
OP
REQ
SD Slave n
...
Figure 32: Fetching SD data in an SPI daisy chain
configuration