ATMEGA32-16PU Atmel, ATMEGA32-16PU Datasheet - Page 178

• Manufacturer Part Number: ATMEGA32-16PU
• Description: IC AVR MCU 32K 16MHZ 5V 40DIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA32-16PU

• 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: 40-DIP (0.600", 15.24mm)
• Processor Series: ATMEGA32x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: 2-Wire/SPI/USART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Operating Supply Voltage: 4.5 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• A/d Inputs: 8-Channel, 10-Bit
• Cpu Speed: 16 MIPS
• Eeprom Memory: 1K Bytes
• Input Output: 32
• Interface: 2-Wire/SPI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 40-pin PDIP
• Programmable Memory: 32K Bytes
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 4.5-5.5 V
• Data Rom Size: 1024 B
• Height: 4.83 mm
• Length: 52.58 mm
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 4.5 V
• Width: 13.97 mm
• Controller Family/series: AVR MEGA
• No. Of I/o's: 32
• Eeprom Memory Size: 1024Byte
• Ram Memory Size: 2KB
• Rohs Compliant: Yes
• For Use With: ATSTK524 - KIT STARTER ATMEGA32M1/MEGA32C1ATSTK600-TQFP32 - STK600 SOCKET/ADAPTER 32-TQFPATSTK600-TQFP44 - STK600 SOCKET/ADAPTER 44-TQFPATSTK600-DIP40 - STK600 SOCKET/ADAPTER 40-PDIP770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATAVRISP2 - PROGRAMMER AVR IN SYSTEMATJTAGICE2 - AVR ON-CHIP D-BUG SYSTEMATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Using the TWI
Figure 85. Interfacing the Application to the TWI in a Typical Transmission
178
Application
Hardware
Action
Action
TWI
TWI bus
ATmega32(L)
writes to TWCR
transmission of
1. Application
START condition sent
Status code indicates
to initiate
START
2. TWINT set.
START
TWDR, and loads appropriate control
3. Check TWSR to see if START was
signals into TWCR, making sure that
TWINT is written to one, and TWSTA
sendt. Application loads SLA+W into
• Bit 0 – TWGCE: TWI General Call Recognition Enable Bit
If set, this bit enables the recognition of a General Call given over the Two-wire Serial
Bus.
The AVR TWI is byte-oriented and interrupt based. Interrupts are issued after all bus
events, like reception of a byte or transmission of a START condition. Because the TWI
is interrupt-based, the application software is free to carry on other operations during a
TWI byte transfer. Note that the TWI Interrupt Enable (TWIE) bit in TWCR together with
the Global Interrupt Enable bit in SREG allow the application to decide whether or not
assertion of the TWINT Flag should generate an interrupt request. If the TWIE bit is
cleared, the application must poll the TWINT Flag in order to detect actions on the TWI
bus.
When the TWINT Flag is asserted, the TWI has finished an operation and awaits appli-
cation response. In this case, the TWI Status Register (TWSR) contains a value
indicating the current state of the TWI bus. The application software can then decide
how the TWI should behave in the next TWI bus cycle by manipulating the TWCR and
TWDR Registers.
Figure 85 is a simple example of how the application can interface to the TWI hardware.
In this example, a master wishes to transmit a single data byte to a slave. This descrip-
tion is quite abstract, a more detailed explanation follows later in this section. A simple
code example implementing the desired behaviour is also presented.
1. The first step in a TWI transmission is to transmit a START condition. This is
2. When the START condition has been transmitted, the TWINT Flag in TWCR is
is written to zero
done by writing a specific value into TWCR, instructing the TWI hardware to
transmit a START condition. Which value to write is described later on. However,
it is important that the TWINT bit is set in the value written. Writing a one to
TWINT clears the Flag. The TWI will not start any operation as long as the
TWINT bit in TWCR is set. Immediately after the application has cleared TWINT,
the TWI will initiate transmission of the START condition.
set, and TWSR is updated with a status code indicating that the START condition
has successfully been sent.
SLA+W
Status code indicates
SLA+W sent, ACK
4. TWINT set.
received
A
Application loads data into TWDR, and
5. Check TWSR to see if SLA+W was
loads appropriate control signals into
TWCR, making sure that TWINT is
sent and ACK received.
written to one
Data
data sent, ACK received
Status code indicates
6. TWINT set.
A
making sure that TWINT is written to one
7. Check TWSR to see if data was sent
Application loads appropriate control
signals to send STOP into TWCR,
STOP
and ACK received.
TWINT set
Indicates
2503G–AVR–11/04