NEC V850ES/F 3-L Series User Manual page 425

Asynchronous Serial Interface (UARTD)
Table 15-5
Division ratio (k)
4
8
20
50
100
255
Note
Similarly, obtaining the following maximum allowable transfer rate yields the
following.
10
×
----- -
FLmax = 11 FL
11
21k 2 –
------------------ -
FLmax =
20k
Therefore, the minimum baud rate that can be received by the destination is as
follows.
(
BRmin FLmax 11
=
Obtaining the allowable baud rate error for UARTDn and the destination from
the above-described equations for obtaining the minimum and maximum baud
rate values yields the following.
Maximum/Minimum allowable baud rate error
Maximum allowable baud rate error
+2.32%
+3.52%
+4.26%
+4.56%
+4.66%
+4.72%
1. The reception accuracy depends on the bit count in 1 frame, the input clock
frequency, and the division ratio (k). The higher the input clock frequency
and the larger the division ratio (k), the higher the accuracy.
2. k: Setting value of UDnCTL2.UDnBRS[7:0]
User's Manual U18743EE1V2UM00
2 21k 2
k +
× ×
----------- - ------------------ -
– FL =
2k 2k
× ×
FL 11
20k
1
–
⁄ ) ×
------------------ -
= Brate
21k 2
–
Minimum allowable baud rate error
-2.43%
-3.61%
-4.30%
-4.58%
-4.67%
-4.72%
–
×
FL
Chapter 15
425