The baud rate transmit/receive clock generated is either a signal scaled from the main system clock, or
a signal scaled from the clock input from the ASCK pin.
(i) Generation of baud rate transmit/receive clock by means of main system clock
The transmit/receive clock is generated by scaling the main system clock. The baud rate generated
from the main system clock is obtained with the following expression.
[Baud rate] =
f
: Main system clock oscillation frequency
X
f
: Main system clock frequency (fx or fx/2)
XX
n
: Value set in TPS0 to TPS3 (1
k
: Value set in MDL0 to MDL3 (0
Table 19-5. Relationship Between Main System Clock and Baud Rate
Baud
Rate
MCS=1
(bps)
BRGC Set Value Error (%) BRGC Set Value Error (%) BRGC Set Value
75
–
110
06H
150
00H
300
E0H
600
D0H
1200
C0H
2400
B0H
4800
A0H
9600
90H
19200
80H
31250
74H
38400
70H
76800
60H
MCS: Oscillation mode selection register (OSMS) bit 0
CHAPTER 19 SERIAL INTERFACE CHANNEL 2
f
XX
[Hz]
n
2
(k+16)
n
11)
k
14)
fx=5.0 MHz
MCS=0
00H
1.73
0.88
E6H
0.88
1.73
E0H
1.73
1.73
D0H
1.73
1.73
C0H
1.73
1.73
B0H
1.73
1.73
A0H
1.73
1.73
90H
1.73
1.73
80H
1.73
1.73
70H
1.73
0
64H
1.73
60H
1.73
1.73
50H
1.73
fx=4.19 MHz
MCS=1
Error (%) BRGC Set Value Error (%)
0BH
1.14
03H
–2.01
EBH
1.14
DBH
1.14
CBH
1.14
BBH
1.14
ABH
1.14
9BH
1.14
8BH
1.14
7BH
1.14
0
71H
–1.31
6BH
1.14
5BH
1.14
MCS=0
EBH
1.14
E3H
–2.01
DBH
1.14
CBH
1.14
BBH
1.14
ABH
1.14
9BH
1.14
8BH
1.14
7BH
1.14
6BH
1.14
61H
–1.31
5BH
1.14
—
—
453