Relationship Between Main System Clock And Baud Rate - NEC PD78056F User Manual

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.
(a) Generation of baud rate transmit/receive clock by means of main system clock
The transmit/receive clocks generated by scaling the main system clock. The baud rate generated from
the main system clock is found from the following expression.
[Baud rate] =
where, f
X
f
XX
n
k
Table 19-3. 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
444
CHAPTER 19 SERIAL INTERFACE CHANNEL 2
f
XX
[Hz]
n
2 (k+16)
: Main system clock oscillation frequency
: Main system clock frequency (fx or fx/2)
: Value set in TPS0 to TPS3 (1
: Value set in MDL0 to MDL3 (0
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
n 11)
k 14)
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
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