ATmega16A Atmel Corporation, ATmega16A Datasheet - Page 180

• Manufacturer Part Number: ATmega16A
• Manufacturer: Atmel Corporation

Specifications of ATmega16A

• Flash (kbytes): 16 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 32
• Ext Interrupts: 3
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• 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): 1
• Eeprom (bytes): 512
• 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: 3
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

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ATmega16A
mode, checking if it is being addressed by the winning Master. The SDA line should be left high,
but losing Masters are allowed to generate a clock signal until the end of the current data or
address packet. Arbitration will continue until only one Master remains, and this may take many
bits. If several Masters are trying to address the same Slave, arbitration will continue into the
data packet.
Figure 20-8. Arbitration between Two Masters
Note that arbitration is not allowed between:
It is the user software’s responsibility to ensure that these illegal arbitration conditions never
occur. This implies that in multi-master systems, all data transfers must use the same composi-
tion of SLA+R/W and data packets. In other words: All transmissions must contain the same
number of data packets, otherwise the result of the arbitration is undefined.
• A REPEATED START condition and a data bit
• A STOP condition and a data bit
• A REPEATED START and a STOP condition
Synchronized
SCL Line
SDA from
SDA from
Master A
Master B
SDA Line
START
Arbitration, SDA
Master A Loses
A
SDA
8154B–AVR–07/09