NEC 78K0 Series User Manual page 346

Minimum permissible data frame length: FLmin = 11 × FL −
Therefore, the maximum receivable baud rate at the transmission destination is as follows.
BRmax = (FLmin/11)
Similarly, the maximum permissible data frame length can be calculated as follows.
10
× FLmax = 11 × FL −
11
21k – 2
FLmax =
20k
Therefore, the minimum receivable baud rate at the transmission destination is as follows.
BRmin = (FLmax/11)
The permissible baud rate error between UART0 and the transmission destination can be calculated from the
above minimum and maximum baud rate expressions, as follows.
Table 14-6. Maximum/Minimum Permissible Baud Rate Error
Division Ratio (k)
8
16
24
31
Remarks 1. The permissible error of reception depends on the number of bits in one frame, input clock
frequency, and division ratio (k). The higher the input clock frequency and the higher the division
ratio (k), the higher the permissible error.
2. k: Set value of BRGC0
346
CHAPTER 14 SERIAL INTERFACE UART0
22k
−
1
= Brate
21k + 2
21k − 2
k + 2
× FL =
FL
2 × k 2 × k
FL × 11
20k
−
1
= Brate
21k − 2
Maximum Permissible Baud Rate Error
+3.53%
+4.14%
+4.34%
+4.44%
Preliminary User's Manual U17260EJ3V1UD
k − 2
21k + 2
× FL =
FL
2k 2k
Minimum Permissible Baud Rate Error
−3.61%
−4.19%
−4.38%
−4.47%