Asynchronous Serial Ports (UARTs)
Am186™CC/CH/CU Microcontrollers User’s Manual
13-15
Figure 13-6
UARTs Clock
13.5.5.1
Programming the Baud Rate
The formula for determining the baud divisor register value is:
BAUDDIV = (clock frequency / (16 • baud rate))
The maximum baud rate is 1/16th of the CPU clock. The processor clock frequency is the
maximum clock frequency supported on the UCLK input. Table 13-3 shows the baud
divisors for various baud rates and clock speeds. Note that the baud divisor value (BDV) is
shown in both decimal and hexadecimal.
Table 13-3
Baud Rate Table for UARTs
Serial Port Clock Frequency (Processor Frequency or UCLK Frequency)
24 MHz
25 MHz
40 MHz
44.2 MHz
48 MHz
50 MHz
Baud Rate
Divisor
% Error
Divisor
% Error
Divisor
% Error
Divisor
% Error
Divisor
% Error
Divisor
% Error
300
5000d
1388h
0
5208d
1458h
0
8333d
208Dh
0
9208d
23F8h
0 10000d
2710h
0 10417d
28B1h
0
600
2500d
09C4h
0
2604d
0A2Ch
0
4167d
1047h
0
4604d
11FCh
0
5000d
1388h
0
5208d
1458h
0
1200
1250d
04E2h
0
1302d
0516h
0
2083d
0823h
0
2302d
08FEh
0
2500d
09C4h
0
2604d
0A2Ch
0
2400
625d
0271h
0
651d
028Bh
0
1042d
0412h
0
1151d
047Fh
0
1250d
04E2h
0
1302d
0516h
0
9600
156d
9Ch
0.2
163d
A3h
-0.1
260d
0104h
0.2
288d
0120h
-0.1
313d
0139h
-0.2
326d
0146h
-0.1
19200
78d
4Eh
0.2
81d
51h
0.5
130d
82h
0.2
144d
90h
-0.1
156d
9Ch
0.2
163d
A3h
-0.1
38400
39d
27h
0.2
41d
29h
-0.8
65d
41h
0.2
72d
48h
-0.1
78d
4Eh
0.2
81d
51h
0.5
57600
26d
1Ah
0.2
27d
1Bh
0.5
43d
2Bh
0.9
48d
30h
-0.1
52d
34h
0.2
54d
36h
0.5
115200
13d
0Dh
0.2
14d
0Eh
-3.2
22d
16h
-1.4
24d
18h
-0.1
26d
1Ah
0.2
27d
1Bh
0.5
230400
7d
07h
-7.5
7d
07h
-3.2
11d
0Bh
-1.4
12d
0Ch
-0.1
13d
0Dh
0.2
14d
0Eh
-3.2
460800
3d
03h
7.8
3d
03h
11.5
5d
05h
7.8
6d
06h
-0.1
7d
07h
-7.5
7d
07h
-3.2
baud
divisor
CPU Clock
UCLK
Divide
Autobaud clock (High-Speed UART only)
(HS)UART Clock Select
clock
for
oversampling
Stage 1
Oversample
Baud clock
Содержание Am186 CC
Страница 1: ...Am186 CC CH CU Microcontrollers User s Manual Order 21914B...
Страница 4: ...iv Am186 CC CH CU Microcontrollers User s Manual...
Страница 18: ...Table of Contents xviii Am186 CC CH CU Microcontrollers User s Manual...
Страница 24: ...Introduction xxiv Am186 CC CH CU Microcontrollers User s Manual...
Страница 39: ...Architectural Overview Am186 CC CH CU Microcontrollers User s Manual 1 15 Figure 1 6 32 Channel Linecard CH CC...
Страница 40: ...Architectural Overview 1 16 Am186 CC CH CU Microcontrollers User s Manual...
Страница 86: ...System Overview 3 36 Am186 CC CH CU Microcontrollers User s Manual...
Страница 92: ...Emulator Support 4 6 Am186 CC CH CU Microcontrollers User s Manual...
Страница 112: ...DRAM Controller 6 8 Am186 CC CH CU Microcontrollers User s Manual...
Страница 134: ...Interrupts 7 22 Am186 CC CH CU Microcontrollers User s Manual...
Страница 186: ...Programmable I O Signals 9 8 Am186 CC CH CU Microcontrollers User s Manual...
Страница 200: ...Watchdog Timer 11 6 Am186 CC CH CU Microcontrollers User s Manual...
Страница 232: ...Asynchronous Serial Ports UARTs 13 24 Am186 CC CH CU Microcontrollers User s Manual...
Страница 242: ...Synchronous Serial Port SSI 14 10 Am186 CC CH CU Microcontrollers User s Manual...
Страница 264: ...High Level Data Link Control HDLC 15 22 Am186 CC CH CU Microcontrollers User s Manual...
Страница 332: ...Universal Serial Bus USB 18 34 Am186 CC CH CU Microcontrollers User s Manual...
Страница 348: ...Register Summary A 16 Am186 CC CH CU Microcontrollers User s Manual...
Страница 376: ...Index Index 18 Am186 CC CH CU Microcontrollers User s Manual...