MC72000 Freescale Semiconductor, MC72000 Datasheet - Page 52

• Manufacturer Part Number: MC72000
• Description: Integrated Bluetooth Radio
• Manufacturer: Freescale Semiconductor

Hardware Functional Description
7.2.3 Fractional Divider
The high-speed UART is clocked with the IP bus clock (in the MC72000 typically 24 MHz). This high
frequency clock plus an internal fractional divider enables a wide range of frequencies that is calculated
using the following equations:
In 16 times oversampling mode (xTIM=0 in the UART control register), the following equation is used to
calculate the baud rate.
In 8 times oversampling mode (xTIM=1 in the UART control register), the following equation is used to
calculate the baud rate.
The internal baud rate generator is shown in Figure 31.
Values for INC and MOD that yield standard baud rates at an input clock of 24 MHz/12 MHz are shown in
Table 26.
52
IPG_CLK
Fractional Divider
Freescale Semiconductor, Inc.
For More Information On This Product,
MC72000 Advance Information Data Sheet
UBRMOD
UBRINC
Figure 31. UART Baud Rate Generator
baudrateX8
audrateX16
baudrate
baudrate
Go to: www.freescale.com
Preliminary
=
=
=
=
ipsclk
baudrateX16
--------------------------------- -
ipsclk
baudrateX8
------------------------------ -
16
8
×
Divide by 8 or 16
×
INC
------------------- -
INC
------------------- -
MOD
MOD
+
+
1
1
Baud Rate
Sample Clock
MOTOROLA