ATSAM3S4AA-MU Atmel, ATSAM3S4AA-MU Datasheet - Page 682

• Manufacturer Part Number: ATSAM3S4AA-MU
• Description: IC MCU 32BIT 256KB FLASH 48QFN
• Manufacturer: Atmel
• Series: SAM3Sr

Specifications of ATSAM3S4AA-MU

• Core Processor: ARM® Cortex-M3™
• Core Size: 32-Bit
• Speed: 64MHz
• Connectivity: I²C, MMC, SPI, SSC, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, DMA, I²S, POR, PWM, WDT
• Number Of I /o: 34
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Ram Size: 48K x 8
• Voltage - Supply (vcc/vdd): 1.62 V ~ 1.95 V
• Data Converters: A/D 8x10/12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-VQFN Exposed Pad, 48-HVQFN, 48-SQFN, 48-DHVQFN
• Processor Series: ATSAM3x
• Core: ARM Cortex M3
• 3rd Party Development Tools: JTRACE-CM3, MDK-ARM, RL-ARM, ULINK2
• Development Tools By Supplier: ATSAM3S-EK
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

Table 33-5.
33.7.1.2
682
682
Baud Rate Calculation Example
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
3 686 400
4 915 200
5 000 000
7 372 800
8 000 000
MHz
SAM3S Preliminary
SAM3S Preliminary
Fractional Baud Rate in Asynchronous Mode
Baud Rate Example (OVER = 0)
Expected Baud
This gives a maximum baud rate of MCK divided by 8, assuming that MCK is the highest possi-
ble clock and that OVER is programmed to 1.
Table 33-5
clock frequencies. This table also shows the actual resulting baud rate and the error.
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%.
The Baud Rate generator previously defined is subject to the following limitation: the output fre-
quency changes by only integer multiples of the reference frequency. An approach to this
problem is to integrate a fractional N clock generator that has a high resolution. The generator
architecture is modified to obtain Baud Rate changes by a fraction of the reference source clock.
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
Rate
Bit/s
BaudRate
Error
shows calculations of CD to obtain a baud rate at 38400 bauds for different source
=
1
–
Calculation Result
=
⎛
⎝
ExpectedBaudRate
-------------------------------------------------- -
MCK
ActualBaudRate
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
6.00
8.00
8.14
⁄
CD
×
16
⎞
⎠
CD
12
13
20
20
23
24
30
39
40
40
52
53
54
65
81
6
8
8
Actual 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
Bit/s
6500C–ATARM–8-Feb-11
6500C–ATARM–8-Feb-11
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%
Error