MC9S12G FREESCALE [Freescale Semiconductor, Inc], MC9S12G Datasheet - Page 614

• Manufacturer Part Number: MC9S12G
• Description: Ignores external trigger. Performs one conversion sequence and stops.
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Serial Peripheral Interface (S12SPIV5)
19.3.2.5
Read: Anytime; read data only valid when SPIF is set
Write: Anytime
614
Reset
Reset
This document is valid for the S12G96 and the S12G128 device. All information related to other devices is preliminary.
W
W
R
R
The SPI data register is both the input and output register for SPI data. A write to this register
allows data to be queued and transmitted. For an SPI configured as a master, queued data is
transmitted immediately after the previous transmission has completed. The SPI transmitter empty
flag SPTEF in the SPISR register indicates when the SPI data register is ready to accept new data.
Received data in the SPIDR is valid when SPIF is set.
If SPIF is cleared and data has been received, the received data is transferred from the receive shift
register to the SPIDR and SPIF is set.
If SPIF is set and not serviced, and a second data value has been received, the second received data
is kept as valid data in the receive shift register until the start of another transmission. The data in
the SPIDR does not change.
If SPIF is set and valid data is in the receive shift register, and SPIF is serviced before the start of
a third transmission, the data in the receive shift register is transferred into the SPIDR and SPIF
remains set (see
If SPIF is set and valid data is in the receive shift register, and SPIF is serviced after the start of a
third transmission, the data in the receive shift register has become invalid and is not transferred
into the SPIDR (see
3
R15
T15
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.
R7
T7
SPI Data Register (SPIDR = SPIDRH:SPIDRL)
0
0
7
7
Figure
R14
T14
R6
T6
0
0
6
6
Figure
Figure 19-7. SPI Data Register High (SPIDRH)
Figure 19-8. SPI Data Register Low (SPIDRL)
19-9).
MC9S12G Family Reference Manual,
19-10).
R13
T13
R5
T5
5
0
5
0
R12
T12
R4
T4
0
0
4
4
R11
T11
R3
T3
0
0
3
3
Rev.1.01
R10
T10
R2
T2
2
0
2
0
Freescale Semiconductor
R9
R1
T9
T1
0
0
1
1
R8
T8
R0
T0
0
0
0
0