IC-MHM Datasheet, PDF (47/63 Pages) IC-Haus GmbH – 14-BIT ABSOLUTE ANGLE HALL ENCODER

iC-MHM
14-BIT ABSOLUTE ANGLE HALL ENCODER
Rev D1, Page 47/63
PACTIVE
Code
0
1
Note
Description
Sensor data channel deactivated
Sensor data channel activated*)
*) default after startup
Position Read
The Position Read command (0xA6) is used to read the
absolute position data from the iC-MHM.
Table 92: PACTIVE
With only one iC-MHM slave (one register and one sen-
sor data channel), the RACTIVE and PACTIVE bits are
bits 1 and 0 respectively in the data byte following the
Activate command as shown in Figure 28.
CS
REQ
NCS
SCLK
MOSI
OP
MISO
OP
SD1 SD2
...
8 cycles
Figure 29: Position Read
SCLK
MOSI
MISO
OP
1 0 0 0 0 0 RA PA
OP
00100000
8 cycles
RACTIVE / PACTIVE vector
As shown in Figure 29, the iC-MHM latches its position
data on the first rising edge of SCLK when NCS is low
(REQ).
Figure 28: RACTIVE and PACTIVE (one slave)
If RACTIVE = 1, the register data channel is activated
and communication with iC-MHM registers is possible.
If PACTIVE = 1, the sensor data channel is activated
and position (multiturn count and angle) information
can be read. Both channels can be active at the same
time. After startup, both the register data channel (RAC-
TIVE = 1) and the sensor data channel are enabled
(PACTIVE = 1).
Note: It is not possible for the SPI master to read back
the state of the RACTIVE or PACTIVE bits to deter-
mine which data channels are active in the iC-MHM. It
is only possible for it to turn both channels off and then
activate each or both as required using the Activate
command.
If RACTIVE = 1, the Register Read, Register Write, Reg-
ister Read (Continuous), Register Write (Continuous),
Register Status, Read Status, and Write Instruction
commands (opcodes) operate normally, as explained
following. If RACTIVE = 0, these commands are not
executed and, if attempted, set the error bit in the SPI
status byte (Table 96 on page 50).
Likewise, if PACTIVE = 1, the Position Read opcode op-
erates normally, as explained following. If PACTIVE =
0, this command is not executed and, if attempted, sets
the error bit in the SPI status byte (Table 96 on page
50). All of these commands, however, are still passed
through to MISO.
The sensor data channel must be activated (PACTIVE =
1) for proper operation of this command, otherwise the
error bit in the SPI status byte is set. If invalid data
is detected in the shift register, the error bit in the SPI
status byte (Table 96 on page 50) is set.
The Position Read command data contains the multi-
turn position (turns count) followed by the singleturn
position (angle), an error bit, and a warning bit. All
values are byte-aligned and transmitted MSB first in the
order shown in Table 93.
Position Data Format
Byte
Length
Description
0-4
Multiturn Position (Turns Count - OFFS_MT)
2
Singleturn Position (Magnet Angle - OFFS_ST)
1
nERR, nWARN, 000000
Table 93: Position Data Format
Refer to POSITION OFFSET AND PRESET (Zero Po-
sition) on page 55 for more information on the position
offset parameters OFFS_MT and OFFS_ST.
The number of multiturn bytes in the position data is
determined by parameter RESO_MT.