C8051F521-C-IM View Datasheet(PDF) - Silicon Laboratories

Part Name

Description

MFG CO.

C8051F521-C-IM

8/4/2 kB ISP Flash MCU Family

Silicon Laboratories 

C8051F52x/F53x

Table 17.1. Baud-Rate Calculation Variable Ranges

Factor

prescaler

multiplier

divider

Range

0…3

0…31

200…511

Important: The minimum system clock (SYSCLK) to operate the LIN peripheral is 8 MHz.

Use the following equations to calculate the values for the variables for the baud-rate equation:

multiplier = -------2---0---0---0---0------- – 1

baud_rate

prescaler = ln ---m-----u---l--t--i--p---l--i--e---r----+---S--1--Y---S----C---b-L--a--K--u---d---_----r--a----t--e---------2---0---0-

 ---1---- – 1

ln2

divider

=

-----------------------------------------------S----Y---S----C----L----K-------------------------------------------------

2prescaler + 1  multiplier + 1  baud_rate

It is important to note that in all these equations, the results must be rounded down to the nearest integer.

The following example shows the steps for calculating the baud rate values for a Master node running at

24.5 MHz and communicating at 19200 bits/sec. First, calculate the multiplier:

multiplier = 2----0---0---0---0- – 1 = 0.0417  0

19200

Next, calculate the prescaler:

prescaler

=

l n ---0----+-----1---2---4---5---10---90---20---00---00---------2---0---0--

 ---1---- – 1

ln2

=

1.674  1

Finally, calculate the divider:

divider

=

-------------------2---4---5---0---0---0---0---0--------------------

21 + 1  0 + 1  19200

=

319.010  319

These values lead to the following baud rate:

baud_rate

=

----------------2---4---5---0---0---0---0---0-----------------

21 + 1  0 + 1  319



19200.63

166

Rev. 1.4

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