ATMEGA1284P-AUR Atmel, ATMEGA1284P-AUR Datasheet - Page 195

• Manufacturer Part Number: ATMEGA1284P-AUR
• Description: MCU AVR 128KB FLASH 20MHZ 44TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA1284P-AUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 128KB (64K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

18.12 Examples of Baud Rate Setting
Table 18-9.
1.
8272A–AVR–01/10
Baud
Rate
(bps)
2400
4800
9600
14.4k
19.2k
28.8k
38.4k
57.6k
76.8k
115.2k
230.4k
250k
Max.
(1)
UBRR = 0, Error = 0.0%
UBRR
25
12
6
3
2
1
1
0
–
–
–
–
U2Xn = 0
62.5 kbps
Examples of UBRRn Settings for Commonly Used Oscillator Frequencies
f
Error
-18.6%
osc
-7.0%
0.2%
0.2%
8.5%
8.5%
8.5%
8.5%
–
–
–
–
= 1.0000 MHz
For standard crystal and resonator frequencies, the most commonly used baud rates for asyn-
chronous operation can be generated by using the UBRR settings in
UBRR values which yield an actual baud rate differing less than 0.5% from the target baud rate,
are bold in the table. Higher error ratings are acceptable, but the Receiver will have less noise
resistance when the error ratings are high, especially for large serial frames (see
Operational Range” on page
164A/164PA/324A/324PA/644A/644PA/1284/1284P
UBRR
51
25
12
8
6
3
2
1
1
0
–
–
U2Xn = 1
125 kbps
Error
-18.6%
-3.5%
-7.0%
0.2%
0.2%
0.2%
8.5%
8.5%
8.5%
8.5%
–
–
UBRR
47
23
11
7
5
3
2
1
0
–
–
1
115.2 kbps
U2Xn = 0
Error[%]
187). The error values are calculated using the following equation:
f
Error
-25.0%
osc
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
–
–
= 1.8432 MHz
=
⎛
⎝
BaudRate
------------------------------------------------------- - 1
UBRR
95
47
23
15
11
BaudRate
7
5
3
2
1
0
–
230.4 kbps
U2Xn = 1
Closest Match
Error
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
–
–
UBRR
⎞
⎠
51
25
12
•
8
6
3
2
1
1
0
–
–
U2Xn = 0
125 kbps
100%
f
Error
Table 18-9
-18.6%
osc
-3.5%
-7.0%
0.2%
0.2%
0.2%
8.5%
8.5%
8.5%
8.5%
–
–
= 2.0000 MHz
UBRR
103
to
51
25
16
12
”Asynchronous
8
6
3
2
1
–
0
U2Xn = 1
250 kbps
Table
Error
-3.5%
-7.0%
0.2%
0.2%
0.2%
2.1%
0.2%
8.5%
8.5%
8.5%
0.0%
18-12.
–
195