MC68HC708XL36 FREESCALE [Freescale Semiconductor, Inc], MC68HC708XL36 Datasheet - Page 233

• Manufacturer Part Number: MC68HC708XL36
• Description: HCMOS Microcontroller Unit
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

33-spi_c
MOTOROLA
MODFEN — Mode Fault Enable Bit
SPR1 and SPR0 — SPI Baud Rate Select Bits
Use the following formula to calculate the SPI baud rate:
where:
CGMOUT = base clock output of the clock generator module (CGM)
BD = baud rate divisor
Reset sets the SPTE bit.
This read/write bit, when set to 1, allows the MODF flag to be set. If
the MODF flag is set, clearing the MODFEN does not clear the MODF
flag. If the SPI is enabled as a master and the MODFEN bit is low,
then the SS pin is available for general-purpose I/O.
If the MODFEN bit is set, then this pin is not available for
general-purpose I/O. When the SPI is enabled as a slave, the SS pin
is not available as a general purpose I/O regardless of the value of
MODFEN. (See
If the MODFEN bit is low, the level of the SS pin does not affect the
operation of an enabled SPI configured as a master. For an enabled
SPI configured as a slave, having MODFEN low only prevents the
MODF flag from being set. It does not affect any other part of SPI
operation. (See
In master mode, these read/write bits select one of four baud rates as
shown in
Reset clears SPR1 and SPR0.
Freescale Semiconductor, Inc.
For More Information On This Product,
1 = Transmit data register empty
0 = Transmit data register not empty
SPR1:SPR0
Table
Go to: www.freescale.com
00
01
10
11
Table 5. SPI Master Baud Rate Selection
Mode Fault Error
5. SPR1 and SPR0 have no effect in slave mode.
SS (Slave Select)
Baud rate
SPI
=
BUS CLOCK
--------------------------------- -
on page 218.)
on page 226.)
Baud Rate Divisor (BD)
BD
128
32
2
8
MC68HC708XL36
I/O Registers
233
SPI