TLE5012B
Interfaces
User’s Manual
35
Rev. 1.2, 2018-02
Data communication via SSC
Figure 5-4 SSC bit ordering (read example)
Figure 5-5 Update of update registers
The data communication via SSC interface has the following characteristics:
•
The data transmission order is Most-Significant Bit (MSB) first, Least-Significant Bit (LSB) last.
•
Data is put on the data line with the rising edge of SCK and read with the falling edge of SCK.
•
The SSC Interface is word-aligned. All functions are activated after each transmitted word.
•
After every data transfer with ND
≥
1, the 16-bit Safety Word is appended by the TLE5012B.
•
A “high” condition on the Chip Select pin (CSQ) of the selected TLE5012B interrupts the transfer immediately.
The CRC calculator is automatically reset.
•
After changing the data direction, a delay t
wr_delay
) has to be implemented before continuing the
data transfer. This is necessary for internal register access.
•
If in the Command Word the number of data is greater than 1 (ND > 1), then a corresponding number of
consecutive registers is read, starting at the address given by ADDR.
•
In case an overflow occurs at address 3F
H
, the transfer continues at address 00
H
.
•
If in the Command Word the number of data is zero (ND = 0), the register at the address given by ADDR is
read, but no Safety Word is sent by the TLE5012B. This allows a fast readout of one register.
•
At a rising edge of CSQ without a preceding data transfer (no SCK pulse, see
), the content of all
registers which have an update buffer is saved into the buffer. This procedure serves to take a snapshot of all
relevant sensor parameters at a given time. The content of the update buffer can then be read by sending a
read command for the desired register and setting the UPD bit of the Command Word to “1”.
•
After sending the Safety Word, the transfer ends. To start another data transfer, the CSQ has to be deselected
once for at least t
CSoff
.
•
By default, the SSC interface is set to push-pull. The push-pull driver is active only if the TLE5012B has to send
data, otherwise the DATA pin is set to high-impedance.
SCK
DATA
8
11
10
9
MSB
14
13
12
CSQ
SSC Transfer
LSB
3
2
1
7 6
5
4
Command Word
Data Word (s)
SSC -Master is driving DAT A
SSC -Slave is driving DAT A
LSB
1
RW
ADDR
LENGTH
LOCK
MSB
t
wr_delay
UPD
SCK
DATA
CSQ
LSB
LSB
MSB
Command Word
Data Word (s)
Update -Signal
Update -Event
SSC -Master is driving DAT A
SSC -Slave is driving DAT A
t
CSupdate