AT91SAM9XE128-QU Atmel, AT91SAM9XE128-QU Datasheet - Page 498

• Manufacturer Part Number: AT91SAM9XE128-QU
• Description: MCU ARM9 128K FLASH 208-PQFP
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91SAM9XE128-QU

• Core Processor: ARM9
• Core Size: 16/32-Bit
• Speed: 180MHz
• Connectivity: EBI/EMI, Ethernet, I²C, MMC, SPI, SSC, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 96
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: FLASH
• Ram Size: 40K x 8
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Data Converters: A/D 4x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 208-MQFP, 208-PQFP
• Processor Series: AT91SAMx
• Core: ARM926EJ-S
• Data Bus Width: 32 bit
• Data Ram Size: 16 KB
• Interface Type: 2-Wire, EBI, I2S, SPI, USART
• Maximum Clock Frequency: 180 MHz
• Number Of Programmable I/os: 96
• Number Of Timers: 6
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: JTRACE-ARM-2M, KSK-AT91SAM9XE-PL, MDK-ARM, RL-ARM, ULINK2
• Development Tools By Supplier: AT91SAM-ICE, AT91-ISP, AT91SAM9XE-EK
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 4 Channel
• For Use With: AT91SAM9XE-EK - KIT EVAL FOR AT91SAM9XEAT91SAM-ICE - EMULATOR FOR AT91 ARM7/ARM9
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

34.6.1.2
Table 34-2.
34.6.1.3
6254C–ATARM–22-Jan-10
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
Baud Rate Calculation Example
Fractional Baud Rate in Asynchronous Mode
Baud Rate Example (OVER = 0)
Expected Baud
Table 34-2
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.
This fractional part is programmed with the FP field in the Baud Rate Generator Register
(US_BRGR). If FP is not 0, the fractional part is activated. The resolution is one eighth of the
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
-------------------------------------------------------- -
ActualBaudRate
MCK
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
AT91SAM9XE128/256/512 Preliminary
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
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
498