ATMEGA32U4-AU Atmel, ATMEGA32U4-AU Datasheet - Page 200

MCU AVR 32K FLASH 16MHZ 44-TQFP

ATMEGA32U4-AU

Manufacturer Part Number
ATMEGA32U4-AU
Description
MCU AVR 32K FLASH 16MHZ 44-TQFP
Manufacturer
Atmel
Series
AVR® ATmegar

Specifications of ATMEGA32U4-AU

Core Processor
AVR
Core Size
8-Bit
Speed
16MHz
Connectivity
I²C, SPI, UART/USART, USB
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
26
Program Memory Size
32KB (16K x 16)
Program Memory Type
FLASH
Eeprom Size
1K x 8
Ram Size
2.5K x 8
Voltage - Supply (vcc/vdd)
2.7 V ~ 5.5 V
Data Converters
A/D 12x10b
Oscillator Type
External
Operating Temperature
-40°C ~ 85°C
Package / Case
44-TQFP, 44-VQFP
Processor Series
ATMEGA32x
Core
AVR8
Data Bus Width
8 bit
Data Ram Size
2.5 KB
Interface Type
SPI/TWI/USART
Maximum Clock Frequency
16 MHz
Number Of Programmable I/os
26
Number Of Timers
5
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
3rd Party Development Tools
EWAVR, EWAVR-BL
Development Tools By Supplier
ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
Minimum Operating Temperature
- 40 C
On-chip Adc
12-ch x 10-bit
Cpu Family
ATmega
Device Core
AVR
Device Core Size
8b
Frequency (max)
16MHz
Total Internal Ram Size
2.5KB
# I/os (max)
26
Number Of Timers - General Purpose
5
Operating Supply Voltage (typ)
3.3/5V
Operating Supply Voltage (max)
5.5V
Operating Supply Voltage (min)
2.7V
Instruction Set Architecture
RISC
Operating Temp Range
-40C to 85C
Operating Temperature Classification
Industrial
Mounting
Surface Mount
Pin Count
44
Package Type
TQFP
Controller Family/series
AVR MEGA
No. Of I/o's
26
Eeprom Memory Size
1KB
Ram Memory Size
2.5KB
Cpu Speed
16MHz
Rohs Compliant
Yes
For Use With
ATSTK524 - KIT STARTER ATMEGA32M1/MEGA32C1ATSTK600 - DEV KIT FOR AVR/AVR32ATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATSTK500 - PROGRAMMER AVR STARTER KIT
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
ATMEGA32U4-16AU
ATMEGA32U4-16AU

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATMEGA32U4-AU
Manufacturer:
FREESCALE
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125
Part Number:
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Manufacturer:
Atmel
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18.7.2
7766F–AVR–11/10
Asynchronous Data Recovery
Figure 18-5. Start Bit Sampling
When the clock recovery logic detects a high (idle) to low (start) transition on the RxDn line, the
start bit detection sequence is initiated. Let sample 1 denote the first zero-sample as shown in
the figure. The clock recovery logic then uses samples 8, 9, and 10 for Normal mode, and sam-
ples 4, 5, and 6 for Double Speed mode (indicated with sample numbers inside boxes on the
figure), to decide if a valid start bit is received. If two or more of these three samples have logical
high levels (the majority wins), the start bit is rejected as a noise spike and the Receiver starts
looking for the next high to low-transition. If however, a valid start bit is detected, the clock recov-
ery logic is synchronized and the data recovery can begin. The synchronization process is
repeated for each start bit.
When the receiver clock is synchronized to the start bit, the data recovery can begin. The data
recovery unit uses a state machine that has 16 states for each bit in Normal mode and eight
states for each bit in Double Speed mode.
the parity bit. Each of the samples is given a number that is equal to the state of the recovery
unit.
Figure 18-6. Sampling of Data and Parity Bit
The decision of the logic level of the received bit is taken by doing a majority voting of the logic
value to the three samples in the center of the received bit. The center samples are emphasized
on the figure by having the sample number inside boxes. The majority voting process is done as
follows: If two or all three samples have high levels, the received bit is registered to be a logic 1.
If two or all three samples have low levels, the received bit is registered to be a logic 0. This
majority voting process acts as a low pass filter for the incoming signal on the RxDn pin. The
recovery process is then repeated until a complete frame is received. Including the first stop bit.
Note that the Receiver only uses the first stop bit of a frame.
Figure 18-7
of the next frame.
(U2X = 0)
(U2X = 1)
Sample
Sample
(U2X = 0)
(U2X = 1)
Sample
Sample
RxD
RxD
shows the sampling of the stop bit and the earliest possible beginning of the start bit
0
0
IDLE
0
1
1
1
1
2
2
3
2
3
2
4
4
5
3
5
3
6
6
Figure 18-6
7
4
7
4
8
8
START
BIT n
9
5
9
5
10
10
shows the sampling of the data bits and
11
11
6
6
12
12
ATmega16/32U4
13
13
7
7
14
14
15
8
15
8
16
16
1
1
1
1
2
BIT 0
3
2
200

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