ATMEGA128-16AI Atmel, ATMEGA128-16AI Datasheet - Page 185

• Manufacturer Part Number: ATMEGA128-16AI
• Description: IC AVR MCU 128K 16MHZ 64-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA128-16AI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 128KB (64K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• For Use With: ATSTK501 - ADAPTER KIT FOR 64PIN AVR MCU
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: Q1167170A

Asynchronous
Operational Range
2467V–AVR–02/11
Figure 85. Stop Bit Sampling and Next Start Bit Sampling
The same majority voting is done to the stop bit as done for the other bits in the frame. If the stop
bit is registered to have a logic 0 value, the Frame Error (FE) flag will be set.
A new high to low transition indicating the start bit of a new frame can come right after the last of
the bits used for majority voting. For Normal Speed mode, the first low level sample can be at
point marked (A) in
(C) marks a stop bit of full length. The early start bit detection influences the operational range of
the receiver.
The operational range of the Receiver is dependent on the mismatch between the received bit
rate and the internally generated baud rate. If the Transmitter is sending frames at too fast or too
slow bit rates, or the internally generated baud rate of the receiver does not have a similar (see
Table
The following equations can be used to calculate the ratio of the incoming data rate and internal
receiver baud rate.
D
S
S
S
R
baud rate. R
the receiver baud rate.
Table 75
normal speed mode has higher toleration of baud rate variations.
F
M
slow
(U2X = 0)
(U2X = 1)
Sample
Sample
is the ratio of the slowest incoming data rate that can be accepted in relation to the receiver
Sum of character size and parity size (D = 5 to 10-bit)
Samples per bit. S = 16 for Normal Speed mode and S = 8 for Double Speed
mode.
First sample number used for majority voting. S
for Double Speed mode.
Middle sample number used for majority voting. S
S
RxD
75) base frequency, the Receiver will not be able to synchronize the frames to the start bit.
M
and
= 5 for Double Speed mode.
R
slow
fast
Table 76
is the ratio of the fastest incoming data rate that can be accepted in relation to
=
Figure
------------------------------------------ -
S 1
–
1
1
list the maximum receiver baud rate error that can be tolerated. Note that
(
D
+
2
85. For Double Speed mode the first low level must be delayed to (B).
+
D S ⋅
1
3
2
)S
+
4
S
F
5
3
6
7
4
8
STOP 1
9
5
F
10
= 8 for Normal Speed and S
M
R
= 9 for Normal Speed and
fast
(A)
0/1
6
=
0/1
-----------------------------------
(
D
(B)
0/1
0/1
(
+
D
1
+
)S
2
ATmega128
)S
+
S
M
(C)
F
= 4
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