Справочник Пользователя для IBM uPD78082
146
CHAPTER 11 SERIAL INTERFACE CHANNEL 2
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] = [Hz]
where,
f
X
: Main system clock oscillation frequency
f
XX
: Main system clock frequency (fx or fx/2)
n
: Value set in TPS0 to TPS3 (1
≤
n
≤
11)
k
: Value set in MDL0 to MDL3 (0
≤
k
≤
14)
Table 11-3. Relation between Main System Clock and Baud Rate
fx=5.0 MHz
fx=4.19 MHz
MCS=1
MCS=0
MCS=1
MCS=0
BRGC Set Value Error (%) BRGC Set Value Error (%) BRGC Set Value
Error (%) BRGC Set Value Error (%)
75
–
00H
1.73
0BH
1.14
EBH
1.14
110
06H
0.88
E6H
0.88
03H
–2.01
E3H
–2.01
150
00H
1.73
E0H
1.73
EBH
1.14
DBH
1.14
300
E0H
1.73
D0H
1.73
DBH
1.14
CBH
1.14
600
D0H
1.73
C0H
1.73
CBH
1.14
BBH
1.14
1200
C0H
1.73
B0H
1.73
BBH
1.14
ABH
1.14
2400
B0H
1.73
A0H
1.73
ABH
1.14
9BH
1.14
4800
A0H
1.73
90H
1.73
9BH
1.14
8BH
1.14
9600
90H
1.73
80H
1.73
8BH
1.14
7BH
1.14
19200
80H
1.73
70H
1.73
7BH
1.14
6BH
1.14
31250
74H
0
64H
0
71H
–1.31
61H
–1.31
38400
70H
1.73
60H
1.73
6BH
1.14
5BH
1.14
76800
60H
1.73
50H
1.73
5BH
1.14
—
—
Remark
MCS: Oscillation mode selection register (OSMS) bit 0
f
XX
2
n
×
(k+16)
Baud
Rate
(bps)
★