ATMEGA48-20AI Atmel, ATMEGA48-20AI Datasheet - Page 218

IC AVR MCU 4K 5V 20MHZ 32-TQFP

ATMEGA48-20AI

Manufacturer Part Number
ATMEGA48-20AI
Description
IC AVR MCU 4K 5V 20MHZ 32-TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA48-20AI

Core Processor
AVR
Core Size
8-Bit
Speed
20MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
23
Program Memory Size
4KB (2K x 16)
Program Memory Type
FLASH
Eeprom Size
256 x 8
Ram Size
512 x 8
Voltage - Supply (vcc/vdd)
2.7 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
32-TQFP, 32-VQFP
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Other names
ATMEGA48-24AI
ATMEGA48-24AI

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATMEGA48-20AI
Manufacturer:
Atmel
Quantity:
10 000
218
ATmega48/88/168
2. When the START condition has been transmitted, the TWINT Flag in TWCR is set, and
3. The application software should now examine the value of TWSR, to make sure that the
4. When the address packet has been transmitted, the TWINT Flag in TWCR is set, and
5. The application software should now examine the value of TWSR, to make sure that the
6. When the data packet has been transmitted, the TWINT Flag in TWCR is set, and TWSR
7. The application software should now examine the value of TWSR, to make sure that the
Even though this example is simple, it shows the principles involved in all TWI transmissions.
These can be summarized as follows:
• When the TWI has finished an operation and expects application response, the TWINT Flag is
set. The SCL line is pulled low until TWINT is cleared.
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.
TWSR is updated with a status code indicating that the START condition has success-
fully been sent.
START condition was successfully transmitted. If TWSR indicates otherwise, the applica-
tion software might take some special action, like calling an error routine. Assuming that
the status code is as expected, the application must load SLA+W into TWDR. Remember
that TWDR is used both for address and data. After TWDR has been loaded with the
desired SLA+W, a specific value must be written to TWCR, instructing the TWI hardware
to transmit the SLA+W present in TWDR. 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 address packet.
TWSR is updated with a status code indicating that the address packet has successfully
been sent. The status code will also reflect whether a Slave acknowledged the packet or
not.
address packet was successfully transmitted, and that the value of the ACK bit was as
expected. If TWSR indicates otherwise, the application software might take some special
action, like calling an error routine. Assuming that the status code is as expected, the
application must load a data packet into TWDR. Subsequently, a specific value must be
written to TWCR, instructing the TWI hardware to transmit the data packet present in
TWDR. 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 data packet.
is updated with a status code indicating that the data packet has successfully been sent.
The status code will also reflect whether a Slave acknowledged the packet or not.
data packet was successfully transmitted, and that the value of the ACK bit was as
expected. If TWSR indicates otherwise, the application software might take some special
action, like calling an error routine. Assuming that the status code is as expected, the
application must write a specific value to TWCR, instructing the TWI hardware to transmit
a STOP 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 STOP condi-
tion. Note that TWINT is NOT set after a STOP condition has been sent.
2545S–AVR–07/10

Related parts for ATMEGA48-20AI