AT91RM9200-QI-002 Atmel, AT91RM9200-QI-002 Datasheet - Page 416

• Manufacturer Part Number: AT91RM9200-QI-002
• Description: IC ARM9 MCU 208 PQFP
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91RM9200-QI-002

• Core Processor: ARM9
• Core Size: 16/32-Bit
• Speed: 180MHz
• Connectivity: EBI/EMI, Ethernet, I²C, MMC, SPI, SSC, UART/USART, USB
• Peripherals: POR
• Number Of I /o: 122
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: ROM
• Ram Size: 48K x 8
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 208-MQFP, 208-PQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -

30.6.1.2
416
Baud Rate Calculation Example
AT91RM9200
Baud Rate in Synchronous Mode
Table 30-2
clock frequencies. This table also shows the actual resulting baud rate and the error.
Table 30-2.
The baud rate is calculated with the following formula:
The baud rate error is calculated with the following formula. It is not recommended to work with
an error higher than 5%.
If the USART is programmed to operate in synchronous mode, the selected clock is simply
divided by the field CD in US_BRGR.
Source Clock
12 000 000
12 288 000
14 318 180
14 745 600
18 432 000
24 000 000
24 576 000
25 000 000
32 000 000
32 768 000
33 000 000
40 000 000
50 000 000
60 000 000
70 000 000
3 686 400
4 915 200
5 000 000
7 372 800
8 000 000
BaudRate
Error
MHz
shows calculations of CD to obtain a baud rate at 38400 bauds for different source
=
Baud Rate Example (OVER = 0)
1
–
=
⎛
⎝
ExpectedBaudRate
-------------------------------------------------- -
MCK
Baud Rate
ActualBaudRate
Expected
38 400
38 400
38 400
38 400
38 400
38 400
38 400
38 400
38 400
38 400
38 400
38 400
38 400
38 400
38 400
38 400
38 400
38 400
38 400
38 400
Bit/s
⁄
CD
×
16
Calculation
⎞
⎠
Result
113.93
12.00
13.02
19.53
20.00
23.30
24.00
30.00
39.06
40.00
40.69
52.08
53.33
53.71
65.10
81.38
97.66
6.00
8.00
8.14
114
CD
12
13
20
20
23
24
30
39
40
40
52
53
54
65
81
98
6
8
8
Baud Rate
38 400.00
38 400.00
39 062.50
38 400.00
38 461.54
37 500.00
38 400.00
38 908.10
38 400.00
38 400.00
38 461.54
38 400.00
38 109.76
38 461.54
38 641.51
38 194.44
38 461.54
38 580.25
38 265.31
38 377.19
Actual
Bit/s
1768I–ATARM–09-Jul-09
0.00%
0.00%
1.70%
0.00%
0.16%
2.40%
0.00%
1.31%
0.00%
0.00%
0.16%
0.00%
0.76%
0.16%
0.63%
0.54%
0.16%
0.47%
0.35%
0.06%
Error