saa-xc886clm Infineon Technologies Corporation, saa-xc886clm Datasheet - Page 90

• Manufacturer Part Number: saa-xc886clm
• Description: 8-bit Single Chip Microcontroller
• Manufacturer: Infineon Technologies Corporation

fractional divider) for generating a wide range of baud rates based on its input clock
see
Figure 29
The baud rate timer is a count-down timer and is clocked by either the output of the
fractional divider (
output of the prescaler (
generation, the fractional divider must be configured to fractional divider mode
(FDCON.FDM = 0). This allows the baud rate control run bit BCON.R to be used to start
or stop the baud rate timer. At each timer underflow, the timer is reloaded with the 8-bit
reload value in register BG and one clock pulse is generated for the serial channel.
Enabling the fractional divider in normal divider mode (FDEN = 1 and FDM = 1) stops the
baud rate timer and nullifies the effect of bit BCON.R. See
The baud rate (
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Data Sheet
Input clock
Prescaling factor (2
Fractional divider (STEP/256) defined by register FDSTEP
(to be considered only if fractional divider is enabled and operating in fractional
divider mode)
8-bit reload value (BR_VALUE) for the baud rate timer defined by register BG
f
PCLK
Figure
Prescaler
29.
FDEN
FDM
Baud-rate Generator Circuitry
f
f
PCLK
f
BR
DIV
) value is dependent on the following parameters:
f
MOD
clk
) if the fractional divider is enabled (FDCON.FDEN = 1), or the
BRPRE
f
DIV
Fractional Divider
) if the fractional divider is disabled (FDEN = 0). For baud rate
Adder
) defined by bit field BRPRE in register BCON
FDRES
1
1
FDSTEP
0
f
MOD
‘0’
f
DIV
83
0
(overflow)
FDEN&FDM
10
11
01
00
10
00
01
11
R
0
1
Section
NDOV
Functional Description
8-Bit Baud Rate Timer
8-Bit Reload Value
3.14.
SAA-XC886CLM
V1.0, 2009-09
f
BR
f
PCLK
,