CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U15195EJ5V0UD
434
(c) Baud rate
The baud rate is the value obtained by the following formula.
Baud rate = [bps]
f
CLK
= Frequency [Hz] of base clock selected by TPS3 to TPS0 bits of CKSR0 register.
k = Value set by MDL7 to MDL0 bits of BRGC0 register (k = 8, 9, 10, ..., 255)
(d) Baud rate error
The baud rate error is obtained by the following formula.
[%]
100
1
rate)
baud
(normal
rate
baud
Desired
error)
with
rate
(baud
rate
baud
Actual
(%)
Error
×
−
=
Cautions 1. Make sure that the baud rate error during transmission does not exceed the allowable
error of the reception destination.
2. Make sure that the baud rate error during reception is within the allowable baud rate
range during reception, which is described in (4) Allowable baud rate during
reception.
Example:
Base clock frequency = 20 MHz = 20,000,000 Hz
Setting of MDL7 to MDL0 bits in BRGC0 register = 01000001B (k = 65)
Target baud rate = 153,600 bps
Baud rate = 20M/(2
×
65)
=
20,000,000/(2
×
65) = 153,846 [bps]
Error = (153,846/153,600
−
1)
×
100
=
0.160
[%]
f
CLK
2
×
k
Target