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The baud rate is calculated according to the following formula:
F
UARTCLK
BR = -----------------------------
(BAUDDIV+1) x 16
This yields the following error tolerance calculation:
(BR –BRI)
E
= ----------------- x 100%
p
BRI
The following table shows the baud rate values to be set and the deviations from the standard baud rates. The
associated error percentages are within the baud rate tolerance range.
UART 1 can also be used as a BOOT medium if, for example, functions from an external PC are to be loaded to
the ERTEC 400 and executed. The BOOT medium is selected by the BOOT[2:0] inputs during the active reset
phase.
The BOOT loader then takes over setting of the UART 1 signal pins and loading of the program code. The "Boot
strap loader" functionality is also used.
If the user does not utilize UART 1, it can also be used as a debugging interface.
Copyright © Siemens AG 2010. All rights reserved.
Technical data subject to change
or
BAUDDIV = (-----------------------------) - 1
where BRI is the ideal baud rate
BRI
BAUDDIV
115200
26
76800
40
57600
53
38400
80
19200
162
14400
216
9600
325
2400
1301
1200
2603
110
28408
Table 13: Baud Rates for UART at F
F
UARTCLK
BR x 16
BR
E
%
P
115740
+0.47
76219
-0.76
57870
+0.47
38580
+0.47
19171
-0.15
14400.9
+0.006
9585.9
-0.15
2400.15
+0.006
1200.077
+0.006
110.0004
+0.0003
=50 MHz
UARTCLK
Page
47
ERTEC 400 Manual
Version 1.2.2
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