TLE75008-EMD_15 Datasheet, PDF (52/64 Pages) Infineon Technologies AG – SPI Driver for Enhanced Relay Control

TLE75008-EMD
Serial Peripheral Interface (SPI)
10.5
SPI Protocol
The relationship between SI and SO content during SPI communication is shown in Figure 27. SI line represents
the frame sent from the µC and SO line is the answer provided by TLE75008-EMD.
SI
frame A
frame B
frame C
(previous
SO
response )
response to
frame A
response to
frame B
SPI_ SI2 SO.emf
Figure 27 Relationship between SI and SO during SPI communication
The SPI protocol provides the answer to a command frame only with the next trasmission triggered by the µC.
Although the biggest majority of commands and frames implemented in TLE75008-EMD can be decoded without
the knowledge of what happened before, it is advisable to consider what the µC sent in the previous transmission
to decode TLE75008-EMD response frame completely.
More in detail, the sequence of commands to “read” and “write” the content of a register looks as follows:
SI
write register A
read register A
(new command )
(previous
SO
response )
Standard
diagnostic
register A
content
SPI_RWseq.emf
Figure 28 Register content sent back to µC
There are 3 special situations where the frame sent back to the µC is not related directly to the previous received
frame:
• in case an error in transmission happened during the previous frame (for instance, the clock pulses were not
multiple of 8 with a minimum of 16 bits), shown in Figure 29
• when TLE75008-EMD logic supply comes out of Power-On reset condition or after a Software Reset, as shown
in Figure 30
• in case of command syntax errors
– “write” command starting with “11” instead of “10”
– “read” command starting with “00” instead of “01”
– “read” or “write” commands on registers which are “reserved” or “not used”
Data Sheet
52
Rev. 1.1, 2015-09-25