Micronas SDA 6000, User Manual

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SDA 6000
PRELIMINARY DATA SHEET
Version 2.1
Peripherals
7 - 69 Micronas
According to Table 7-20 a baud rate of 9600 Baud is achieved when register BG is
loaded with a value of 047
H
, assuming that
f
DIV
has been set to 11.0592 MHz.
Table 7-20 also lists a divide factor d
f
which is defined with the following formula:
This divide factor d
f
defines a fixed relationship between the prescaler output frequency
f
DIV
and the baud rate to be detected during the autobaud detection operation. This
means, that changing
f
DIV
results in a totally different baud rate table in terms of baud
rate values. For the baud rates to be detected, the following relations are always valid:
– Br0 = f
DIV
/48
D
, Br1 = f
DIV
/96
D
,

up to Br8 = f
DIV
/9216
D
,
A requirement for detecting standard baud rates up to 230.400 kBaud, is the f
DIV
minimum value of 11.0592 MHz. With the value FD_VALUE in register FDV, the
fractional divider f
DIV
is adapted to the system clock frequency 33 MHz. Table 7-21
defines the deviation of the standard baud rates when using autobaud detection
depending on the system
f
MOD
.
Note: If the deviation of the baud rate after autobaud detection is too high, the baud rate
generator (fractional divider FDV and reload register BG) can be reprogrammed if
required to get a more precise baud rate with less error.
Table 7-20 Autobaud Detection using Standard Baud Rates (
f
DIV
= 11.0592 MHz)
Baud Rate
Numbering Detectable Standard
Baud Rate Divide Factor d
f
BG is Loaded after
Detection with Value
Br0 230.400 kBaud 48 2 = 002
H
Br1 115.200 kBaud 96 5 = 005
H
Br2 57.600 kBaud 192 11 = 00B
H
Br3 38.400 kBaud 288 17 = 011
H
Br4 19.200 kBaud 576 35 = 023
H
Br5 9600 Baud 1152 71 = 047
H
Br6 4800 Baud 2304 143 = 08F
H
Br7 2400 Baud 4608 287 = 11F
H
Br8 1200 Baud 9216 575 = 23F
H
Table 7-21 Standard Baud Rates - Deviations and Errors for Autobaud Detection
f
MOD
FDV Error in f
DIV
33 MHz 172 + 0.24%
baud rate =
f
DIV
d
f