ATMEGA32-16AI Atmel, ATMEGA32-16AI Datasheet - Page 169

• Manufacturer Part Number: ATMEGA32-16AI
• Description: IC AVR MCU 32K 16MHZ IND 44-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA32-16AI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Two-wire Serial
Interface
Features
Two-wire Serial
Interface Bus
Definition
TWI Terminology
2503Q–AVR–02/11
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The Two-wire Serial Interface (TWI) is ideally suited for typical microcontroller applications. The
TWI protocol allows the systems designer to interconnect up to 128 different devices using only
two bi-directional bus lines, one for clock (SCL) and one for data (SDA). The only external hard-
ware needed to implement the bus is a single pull-up resistor for each of the TWI bus lines. All
devices connected to the bus have individual addresses, and mechanisms for resolving bus
contention are inherent in the TWI protocol.
Figure 76. TWI Bus Interconnection
The following definitions are frequently encountered in this section.
Table 72. TWI Terminology
Term
Master
Slave
Transmitter
Receiver
Simple Yet Powerful and Flexible Communication Interface, Only Two Bus Lines Needed
Both Master and Slave Operation Supported
Device Can Operate as Transmitter or Receiver
7-bit Address Space allows up to 128 Different Slave Addresses
Multi-master Arbitration Support
Up to 400kHz Data Transfer Speed
Slew-rate Limited Output Drivers
Noise Suppression Circuitry Rejects Spikes on Bus Lines
Fully Programmable Slave Address with General Call Support
Address Recognition causes Wake-up when AVR is in Sleep Mode
SDA
SCL
Description
The device that initiates and terminates a transmission. The master also
generates the SCL clock.
The device addressed by a master.
The device placing data on the bus.
The device reading data from the bus.
Device 1
Device 2
Device 3
........
Device n
V
CC
ATmega32(L)
R1
R2
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