ATMEGA32HVB-8X3 Atmel, ATMEGA32HVB-8X3 Datasheet - Page 158

• Manufacturer Part Number: ATMEGA32HVB-8X3
• Description: MCU AVR 32KB FLASH 8MHZ 44TSSOP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA32HVB-8X3

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: I²C, SPI
• Peripherals: POR, WDT
• Number Of I /o: 17
• 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 V ~ 25 V
• Data Converters: A/D 7x12b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TSSOP
• Processor Series: ATMEGA32x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: SPI, TWI
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 17
• Number Of Timers: 2
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT, ATAVRSB200
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12 bit, 7 Channel
• Package: 44TSSOP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 8 MHz
• Operating Supply Voltage: 5|9|12|15|18|24 V
• For Use With: ATSTK524 - KIT STARTER ATMEGA32M1/MEGA32C1ATSTK600 - DEV KIT FOR AVR/AVR32ATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

27.3.2
27.3.3
8042B–AVR–06/10
START and STOP Conditions
Address Packet Format
The Master initiates and terminates a data transmission. The transmission is initiated when the
Master issues a START condition on the bus, and it is terminated when the Master issues a
STOP condition. Between a START and a STOP condition, the bus is considered busy, and no
other Master should try to seize control of the bus. A special case occurs when a new START
condition is issued between a START and STOP condition. This is referred to as a REPEATED
START condition, and is used when the Master wishes to initiate a new transfer without relin-
quishing control of the bus. After a REPEATED START, the bus is considered busy until the next
STOP. This is identical to the START behavior, and therefore START is used to describe both
START and REPEATED START for the remainder of this datasheet, unless otherwise noted. As
depicted below, START and STOP conditions are signalled by changing the level of the SDA
line when the SCL line is high.
Figure 27-3. START, REPEATED START, and STOP Conditions
All address packets transmitted on the TWI bus are nine bits long, consisting of seven address
bits, one READ/WRITE control bit and an acknowledge bit. If the READ/WRITE bit is set, a read
operation is to be performed, otherwise a write operation should be performed. When a slave
recognizes that it is being addressed, it should acknowledge by pulling SDA low in the ninth SCL
(ACK) cycle. If the addressed Slave is busy, or for some other reason can not service the Mas-
ter’s request, the SDA line should be left high in the ACK clock cycle. The Master can then
transmit a STOP condition, or a REPEATED START condition to initiate a new transmission. An
address packet consisting of a slave address and a READ or a WRITE bit is called SLA+R or
SLA+W, respectively.
The MSB of the address byte is transmitted first. Slave addresses can freely be allocated by the
designer, but the address 0000 000 is reserved for a general call.
When a general call is issued, all slaves should respond by pulling the SDA line low in the ACK
cycle. A general call is used when a Master wishes to transmit the same message to several
slaves in the system. When the general call address followed by a write bit is transmitted on the
bus, all slaves set up to acknowledge the general call will pull the SDA line low in the ack cycle.
The following data packets will then be received by all the slaves that acknowledged the general
call. Note that transmitting the general call address followed by a Read bit is meaningless, as
this would cause contention if several slaves started transmitting different data.
All addresses of the format 1111 xxx should be reserved for future purposes.
SDA
SCL
START
STOP START
ATmega16HVB/32HVB
REPEATED START
STOP
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