UPD78F9234MC-5A4-A Datasheet, PDF (220/419 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 11 SERIAL INTERFACE UART6
Minimum permissible data frame length: FLmin = 11 × FL − ^{k − 2} × FL = ^{21k + 2} FL
2k
2k
Therefore, the maximum receivable baud rate at the transmission source is as follows.
BRmax = (FLmin/11)^−1 = ^22k Brate
21k + 2
Similarly, the maximum permissible data frame length can be calculated as follows.
10 _{× FLmax = 11 × FL −} k + 2 _{× FL =} 21k − 2 _FL
11
2×k
2×k
FLmax = ^{21k – 2} FL × 11
20k
Therefore, the minimum receivable baud rate at the transmission source is as follows.
BRmin = (FLmax/11)^−1 = ^20k Brate
21k − 2
The permissible baud rate error between UART6 and the transmission source can be calculated from the above
minimum and maximum baud rate expressions, as follows.
Table 11-5. Maximum/Minimum Permissible Baud Rate Error
Division Ratio (k)
Maximum Permissible Baud Rate Error
Minimum Permissible Baud Rate Error
8
+3.53%
−3.61%
20
+4.26%
−4.31%
50
+4.56%
−4.58%
100
+4.66%
−4.67%
255
+4.72%
−4.73%
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 BRGC6
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User’s Manual U17446EJ5V0UD