MC9S08RC8 Datasheet, PDF (177/234 Pages) Freescale Semiconductor, Inc – Microcontrollers

13.4.5 SPI Data Register (SPI1D)
Serial Peripheral Interface (SPI) Module
Bit 7
6
5
4
3
2
Read:
Bit 7
6
5
4
3
2
Write:
Reset: 0
0
0
0
0
0
Figure 13-11. SPI Data Register (SPI1D)
1
Bit 0
1
Bit 0
0
0
Reads of this register return the data read from the receive data buffer. Writes to this register write data
to the transmit data buffer. When the SPI is configured as a master, writing data to the transmit data
buffer initiates an SPI transfer.
Data should not be written to the transmit data buffer unless the SPI transmit buffer empty flag
(SPTEF) is set, indicating there is room in the transmit buffer to queue a new transmit byte.
Data may be read from SPI1D any time after SPRF is set and before another transfer is finished. Failure
to read the data out of the receive data buffer before a new transfer ends causes a receive overrun
condition and the data from the new transfer is lost.
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
Freescale Semiconductor
177