ATMEGA32U4-AU Atmel, ATMEGA32U4-AU Datasheet - Page 238

• 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

20.8
20.8.1
7766F–AVR–11/10
Transmission Modes
Master Transmitter Mode
The TWI can operate in one of four major modes. These are named Master Transmitter (MT),
Master Receiver (MR), Slave Transmitter (ST) and Slave Receiver (SR). Several of these
modes can be used in the same application. As an example, the TWI can use MT mode to write
data into a TWI EEPROM, MR mode to read the data back from the EEPROM. If other masters
are present in the system, some of these might transmit data to the TWI, and then SR mode
would be used. It is the application software that decides which modes are legal.
The following sections describe each of these modes. Possible status codes are described
along with figures detailing data transmission in each of the modes. These figures contain the
following abbreviations:
S: START condition
Rs: REPEATED START condition
R: Read bit (high level at SDA)
W: Write bit (low level at SDA)
A: Acknowledge bit (low level at SDA)
A: Not acknowledge bit (high level at SDA)
Data: 8-bit data byte
P: STOP condition
SLA: Slave Address
In
numbers in the circles show the status code held in TWSR, with the prescaler bits masked to
zero. At these points, actions must be taken by the application to continue or complete the TWI
transfer. The TWI transfer is suspended until the TWINT Flag is cleared by software.
When the TWINT Flag is set, the status code in TWSR is used to determine the appropriate soft-
ware action. For each status code, the required software action and details of the following serial
transfer are given in
these tables.
In the Master Transmitter mode, a number of data bytes are transmitted to a Slave Receiver
(see
The format of the following address packet determines whether Master Transmitter or Master
Receiver mode is to be entered. If SLA+W is transmitted, MT mode is entered, if SLA+R is trans-
mitted, MR mode is entered. All the status codes mentioned in this section assume that the
prescaler bits are zero or are masked to zero.
Figure 20-13
Figure
20-12). In order to enter a Master mode, a START condition must be transmitted.
to
Figure
Table 20-3
20-19, circles are used to indicate that the TWINT Flag is set. The
to
Table
20-6. Note that the prescaler bits are masked to zero in
ATmega16/32U4
238