Serial Peripheral Interface Module (SPI)
15.12.3 SPI Data Register
The SPI data register consists of the read-only receive data register and the
write-only transmit data register. Writing to the SPI data register writes data into the
transmit data register. Reading the SPI data register reads data from the receive
data register. The transmit data and receive data registers are separate registers
that can contain different values. See Figure 15-3.
Address: $0046
Bit 7
R7
6
5
4
3
2
1
Bit 0
R0
Read:
Write:
Reset:
R6
T6
R5
T5
R4
T4
R3
T3
R2
T2
R1
T1
T7
T0
Indeterminate after reset
Figure 15-16. SPI Data Register (SPDR)
R7:R0/T7:T0 — Receive/Transmit Data Bits
NOTE:
Do not use read-modify-write instructions on the SPI data register since the register
read is not the same as the register written.
Data Sheet
232
MC68HC908MR32 • MC68HC908MR16 — Rev. 6.0
Serial Peripheral Interface Module (SPI)
MOTOROLA
FREESCALE [ Freescale ]
