ATMEGA644P-20AQ Atmel, ATMEGA644P-20AQ Datasheet - Page 221

• Manufacturer Part Number: ATMEGA644P-20AQ
• Description: MCU AVR 64K FLASH 20MHZ 44-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644P-20AQ

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K 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-TQFP, 44-VQFP
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Table 18-2.
8011O–AVR–07/10
0x28
0x30
0x38
Data byte has been transmitted;
ACK has been received
Data byte has been transmitted;
NOT ACK has been received
Arbitration lost in SLA+W or data
bytes
Status codes for Master Transmitter Mode
Figure 18-12. Formats and States in the Master Transmitter Mode
Successfull
transmission
to a slave
receiver
Next transfer
started with a
repeated start
condition
Not acknowledge
received after the
slave address
Not acknowledge
received after a data
byte
Arbitration lost in slave
address or data byte
Arbitration lost and
addressed as slave
Load data byte or
No TWDR action or
No TWDR action or
No TWDR action
Load data byte or
No TWDR action or
No TWDR action or
No TWDR action
No TWDR action or
No TWDR action
From master to slave
From slave to master
$08
S
SLA
0
1
0
1
0
1
0
1
0
1
W
MT
0
0
1
1
0
0
1
1
0
0
A or A
DATA
$18
$20
$38
$68
A
A
A
$78
1
1
1
1
1
1
1
1
1
1
Other master
Other master
n
continues
continues
P
$B0
ATmega164P/324P/644P
DATA
X
X
X
X
X
X
X
X
X
X
A
Data byte will be transmitted and ACK or NOT ACK will
be received
Repeated START will be transmitted
STOP condition will be transmitted and
TWSTO Flag will be reset
STOP condition followed by a START condition will be
transmitted and TWSTO Flag will be reset
Data byte will be transmitted and ACK or NOT ACK will
be received
Repeated START will be transmitted
STOP condition will be transmitted and
TWSTO Flag will be reset
STOP condition followed by a START condition will be
transmitted and TWSTO Flag will be reset
2-wire Serial Bus will be released and not addressed
Slave mode entered
A START condition will be transmitted when the bus be-
comes free
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
A or A
$28
$30
$38
To corresponding
states in slave mode
A
A
Other master
$10
continues
R
P
P
S
SLA
W
R
MR
221