Datasheet

Serial Peripheral Interface (S12SPIV5)
S12XS Family Reference Manual, Rev. 1.13
Freescale Semiconductor 445
Table 15-9. SPIF Interrupt Flag Clearing Sequence
Table 15-10. SPTEF Interrupt Flag Clearing Sequence
XFRW Bit SPIF Interrupt Flag Clearing Sequence
0 Read SPISR with SPIF == 1
then
Read SPIDRL
1 Read SPISR with SPIF == 1
then
Byte Read SPIDRL
1
1
Data in SPIDRH is lost in this case.
or
Byte Read SPIDRH
2
2
SPIDRH can be read repeatedly without any effect on SPIF. SPIF Flag is cleared only by the read
of SPIDRL after reading SPISR with SPIF == 1.
Byte Read SPIDRL
or
Word Read (SPIDRH:SPIDRL)
XFRW Bit SPTEF Interrupt Flag Clearing Sequence
0 Read SPISR with SPTEF == 1
then
Write to SPIDRL
1
1
Any write to SPIDRH or SPIDRL with SPTEF == 0 is effectively ignored.
1 Read SPISR with SPTEF == 1
then
Byte Write to SPIDRL
12
2
Data in SPIDRH is undefined in this case.
or
Byte Write to SPIDRH
13
3
SPIDRH can be written repeatedly without any effect on SPTEF. SPTEF Flag is cleared only by
writing to SPIDRL after reading SPISR with SPTEF == 1.
Byte Write to SPIDRL
1
or
Word Write to (SPIDRH:SPIDRL)
1