Datasheet

Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E128 Data Sheet, Rev. 1.07
Freescale Semiconductor 283
9.3.2.3 SPI Baud Rate Register (SPIBR)
Read: anytime
Write: anytime; writes to the reserved bits have no effect
The baud rate divisor equation is as follows:
The baud rate can be calculated with the following equation:
76543210
R0
SPPR2 SPPR1 SPPR0
0
SPR2 SPR1 SPR0
W
Reset 0 0 0 00000
= Unimplemented or Reserved
Figure 9-5. SPI Baud Rate Register (SPIBR)
Table 9-6. SPIBR Field Descriptions
Field Description
6:4
SPPR[2:0]
SPI Baud Rate Preselection Bits — These bits specify the SPI baud rates as shown in Table 9-7. In master
mode, a change of these bits will abort a transmission in progress and force the SPI system into idle state.
2:0
SPR[2:0}
SPI Baud Rate Selection Bits — These bits specify the SPI baud rates as shown in Table 9-7. In master mode,
a change of these bits will abort a transmission in progress and force the SPI system into idle state.
BaudRateDivisor SPPR 1+()2•
SPR 1+()
=
Baud Rate BusClock BaudRateDivisor⁄=