Datasheet

V850ES/JG3 CHAPTER 15 ASYNCHRONOUS SERIAL INTERFACE A (UARTA)
R01UH0015EJ0300 Rev.3.00 Page 478 of 870
Sep 30, 2010
(4) Baud rate
The baud rate is obtained by the following equation.
Baud rate = [bps]
When using the internal clock, the equation will be as follows (when using the ASCKA0 pin as clock at
UARTA0, calculate using the above equation).
Baud rate = [bps]
Remark f
UCLK = Frequency of base clock selected by the UAnCTL1.UAnCKS3 to UAnCTL1.UAnCKS0 bits
f
XX: Main clock frequency
m = Value set using the UAnCTL1.UAnCKS3 to UAnCTL1.UAnCKS0 bits (m = 0 to 10)
k = Value set using the UAnCTL2.UAnBRS7 to UAnCTL2.UAnBRS0 bits (k = 4 to 255)
The baud rate error is obtained by the following equation.
Error (%) = − 1 × 100 [%]
= − 1 × 100 [%]
When using the internal clock, the equation will be as follows (when using the ASCKA0 pin as clock at
UARTA0, calculate the baud rate error using the above equation).
Error (%) = − 1 × 100 [%]
Cautions 1. The baud rate error during transmission must be within the error tolerance on the
receiving side.
2. The baud rate error during reception must satisfy the range indicated in (5) Allowable
baud rate range during reception.
f
UCLK
2 × k
Actual baud rate (baud rate with error)
Target baud rate (correct baud rate)
fXX
2
m+1
× k
fUCLK
2 × k × Target baud rate
f
XX
2
m+1
× k × Target baud rate