AT90CAN64-16AUR Atmel, AT90CAN64-16AUR Datasheet - Page 216

• Manufacturer Part Number: AT90CAN64-16AUR
• Description: MCU AVR 64K FLASH 16MHZ 64TQFP
• Manufacturer: Atmel
• Series: AVR® 90CANr

Specifications of AT90CAN64-16AUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: CAN, EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K 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: 64-TQFP, 64-VQFP
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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AT90CAN32/64/128
Even though this example is simple, it shows the principles involved in all TWI transmissions.
These can be summarized as follows:
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
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
6. When the data packet has been transmitted, the TWINT flag in TWCR is set, and
7. The application software should now examine the value of TWSR, to make sure that
• 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.
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.
the START condition was successfully transmitted. 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 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 success-
fully been sent. The status code will also reflect whether a slave acknowledged the
packet or not.
the 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.
TWSR 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.
the 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 spe-
cial 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 condition. Note that TWINT is NOT set after a STOP condition has been
sent.
7679H–CAN–08/08