mcf5307cft90b Freescale Semiconductor, Inc, mcf5307cft90b Datasheet - Page 329

• Manufacturer Part Number: mcf5307cft90b
• Description: Mcf5307 Coldfire Integrated Microprocessor User
• Manufacturer: Freescale Semiconductor, Inc

14.5.1.2 Calculating Baud Rates
The following sections describe how to calculate baud rates.
14.5.1.2.1 BCLKO Baud Rates
When BCLKO is the UART clocking source, it goes through a divide-by-32 prescaler and
then passes through the 16-bit divider of the concatenated UDUn and UDLn registers.
Using a 45-MHz BCLKO, the baud-rate calculation is as follows:
let baud rate = 9600, then
therefore UDU = 0x00 and UDL = 0x92.
14.5.1.2.2 External Clock
An external source clock (TIN) can be used as is or divided by 16.
14.5.2 Transmitter and Receiver Operating Modes
Figure 14-20 is a functional block diagram of the transmitter and receiver showing the
command and operating registers, which are described generally in the following sections
and described in detail in Section 14.3, “Register Descriptions.”
Divider
Freescale Semiconductor, Inc.
For More Information On This Product,
=
Baudrate
---------------------------- -
[
32 9600
45MHz
Chapter 14. UART Modules
×
Go to: www.freescale.com
Baudrate
]
=
=
Externalclockfrequency
-------------------------------------------------------------------- -
146 decimal
=
(
----------------------------------- -
[
32 divider
45MHz
×
16or1
)
=
0092 hexadecimal
]
(
)
Operation
14-19