ATmega48 Atmel Corporation, ATmega48 Datasheet - Page 225

• Manufacturer Part Number: ATmega48
• Manufacturer: Atmel Corporation

Specifications of ATmega48

• Flash (kbytes): 4 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 23
• Ext Interrupts: 24
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 0.5
• Eeprom (bytes): 256
• Self Program Memory: NO
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Output Compare Channels: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

22.7.2
2545T–AVR–05/11
Master receiver mode
Figure 22-12. Formats and states in the master transmitter mode.
In the Master Receiver mode, a number of data bytes are received from a Slave Transmitter
(Slave see
must be transmitted. 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 transmitted, MR mode is entered. All the status codes mentioned in this
section assume that the prescaler bits are zero or are masked to zero.
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
Figure 22-13 on page
From master to slave
From slave to master
$08
S
SLA
W
226). In order to enter a Master mode, a START condition
MT
A or A
DATA
$18
$20
$38
$68
A
A
A
$78
Other master
Other master
n
continues
continues
P
$B0
DATA
A
Any number of data bytes
and their associated acknowledge bits
This number (contained in TWSR) corresponds
to a defined state of the 2-wire serial bus. The
prescaler bits are zero or masked to zero
A or A
ATmega48/88/168
$28
$30
$38
To corresponding
states in slave mode
A
A
Other master
$10
continues
P
R
P
S
SLA
W
R
MR
225