MC68HC908GT16_07 FREESCALE [Freescale Semiconductor, Inc], MC68HC908GT16_07 Datasheet - Page 216

• Manufacturer Part Number: MC68HC908GT16_07
• Description: Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Serial Peripheral Interface (SPI) Module
SPR1 and SPR0 — SPI Baud Rate Select Bits
16.12.3 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
R7–R0/T7–T0 — Receive/Transmit Data Bits
216
In master mode, these read/write bits select one of four baud rates as shown in
SPR0 have no effect in slave mode. Reset clears SPR1 and SPR0.
Use this formula to calculate the SPI baud rate:
Address: $0012
Do not use read-modify-write instructions on the SPI data register since the
register read is not the same as the register written.
Reset:
Read:
Write:
MC68HC908GT16 • MC68HC908GT8 • MC68HC08GT16 Data Sheet, Rev. 5.0
Bit 7
R7
T7
SPR1 and SPR0
Table 16-3. SPI Master Baud Rate Selection
Figure 16-16. SPI Data Register (SPDR)
R6
T6
Baud rate =
6
00
01
10
11
R5
T5
5
BUSCLK
NOTE
BD
Unaffected by reset
R4
T4
4
Figure
Baud Rate Divisor (BD)
R3
T3
3
16-2.
128
32
2
8
R2
T2
2
R1
T1
1
Table
Freescale Semiconductor
Bit 0
R0
T0
16-3. SPR1 and