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CHAPTER 13 SERIAL INTERFACE (UART0)
Preliminary User’s Manual U16035EJ1V0UM
The transmit/receive clock that is used to generate the baud rate is obtained by dividing the main system
clock.
• Transmit/receive clock generation for baud rate by using main system clock
The main system clock is divided to generate the transmit/receive clock. The baud rate generated from
the main system clock is determined according to the following formula.
[Baud rate] =
f
X
[Hz]
2
n+1
(k + 16)
f
X
:
Main system clock oscillation frequency
When ASCK0 is selected as the source clock of the 5-bit counter, substitute the input clock frequency
to ASCK0 pin for f
X
in the above expression.
n:
Value set via TPS00 to TPS02 (0
≤
n
≤
7)
For details, see
Table 13-2
.
k:
Value set via MDL00 to MDL03 (0
≤
k
≤
14)
Table 13-2 shows the relationship between the 5-bit counter’s source clock assigned to bits 4 to 6 (TPS00
to TPS02) of BRGC0 and the “n” value in the above formula. Table 13-3 shows the relationship between
the main system clock and the baud rate.
Table 13-2. Relationship Between 5-Bit Counter’s Source Clock and “n” Value
TPS02
TPS01
TPS00
5-Bit Counter’s Source Clock Selected
n
0
0
0
P25/ASCK0
0
0
0
1
f
X
/2
1
0
1
0
f
X
/2
2
2
0
1
1
f
X
/2
3
3
1
0
0
f
X
/2
4
4
1
0
1
f
X
/2
5
5
1
1
0
f
X
/2
6
6
1
1
1
f
X
/2
7
7
Remark
f
X
: Main system clock oscillation frequency
