ATMEGA32A-MNR Atmel, ATMEGA32A-MNR Datasheet - Page 163

• Manufacturer Part Number: ATMEGA32A-MNR
• Description: IC MCU AVR 32K 16MHZ 44VQFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA32A-MNR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

19.8.3
8155C–AVR–02/11
Asynchronous Operational Range
Figure 19-7. 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
(B). (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
bit.
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
F
M
slow
(U2X = 0)
(U2X = 1)
Sample
Sample
RxD
19-2) base frequency, the receiver will not be able to synchronize the frames to the start
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
S
Middle sample number used for majority voting. S
S
is the ratio of the slowest incoming data rate that can be accepted in relation to the
receiver baud rate. R
accepted in relation to the receiver baud rate.
F
M
= 4 for Double Speed mode.
= 5 for Double Speed mode.
Figure
1
1
2
19-7. For Double Speed mode the first low level must be delayed to
3
2
4
R
fast
slow
R
5
3
fast
is the ratio of the fastest incoming data rate that can be
6
=
=
------------------------------------------ -
S 1
7
4
-----------------------------------
(
–
D
(
(
+
8
D
D
+
STOP 1
1
+
+
D S ⋅
)S
9
5
2
1
)S
+
)S
10
S
+
M
S
0/1
(A)
F
6
F
0/1
= 8 for Normal Speed and
M
= 9 for Normal Speed and
(B)
0/1
0/1
ATmega32A
(C)
163