ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 244

• Manufacturer Part Number: ATmega32U4
• Manufacturer: Atmel Corporation

Specifications of ATmega32U4

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 14
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 26
• Ext Interrupts: 13
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 12
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 3.3
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 12
• Input Capture Channels: 2
• Pwm Channels: 8
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

20.8.3
7766F–AVR–11/10
Slave Receiver Mode
Figure 20-15. Formats and States in the Master Receiver Mode
In the Slave Receiver mode, a number of data bytes are received from a Master Transmitter
(see
are zero or are masked to zero.
Figure 20-16. Data transfer in Slave Receiver mode
To initiate the Slave Receiver mode, TWAR and TWCR must be initialized as follows:
TWAR
value
Successfull
reception
from a slave
receiver
Next transfer
started with a
repeated start
condition
Not acknowledge
received after the
slave address
Arbitration lost in slave
address or data byte
Arbitration lost and
addressed as slave
Figure
20-16). All the status codes mentioned in this section assume that the prescaler bits
SDA
SCL
From master to slave
From slave to master
$08
S
TWA6
SLA
Device 1
RECEIVER
SLAVE
TWA5
R
MR
TRANSMITTER
A or A
Device 2
DATA
$40
$48
$38
$68
MASTER
A
A
A
TWA4
Device’s Own Slave Address
$78
Other master
Other master
n
continues
continues
P
$B0
DATA
Device 3
TWA3
A
Any number of data bytes
and their associated acknowledge bits
This number (contained in TWSR) corresponds
to a defined state of the Two-Wire Serial Bus. The
prescaler bits are zero or masked to zero
........
TWA2
$50
$38
To corresponding
states in slave mode
A
A
Device n
Other master
DATA
continues
TWA1
V
CC
ATmega16/32U4
$58
A
R1
TWA0
$10
R
P
S
R2
SLA
TWGCE
W
R
MT
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