ATMEGA48V-10MMU Atmel, ATMEGA48V-10MMU Datasheet - Page 235

• Manufacturer Part Number: ATMEGA48V-10MMU
• Description: MCU AVR 4K FLASH 10MHZ 28-QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA48V-10MMU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 10MHz
• 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): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• Processor Series: ATMEGA48x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 512 B
• Interface Type: 2-Wire, SPI, USART, Serial
• Maximum Clock Frequency: 10 MHz
• Number Of Programmable I/os: 23
• Number Of Timers: 3
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 Channel
• Package: 28MLF EP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 10 MHz
• Operating Supply Voltage: 2.5|3.3|5 V
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32ATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVR
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

21.9
21.9.1
21.9.2
2545S–AVR–07/10
Register Description
TWBR – TWI Bit Rate Register
TWCR – TWI Control Register
• Two or more masters are accessing different slaves. In this case, arbitration will occur in the
This is summarized in
Figure 21-21. Possible Status Codes Caused by Arbitration
• Bits 7..0 – TWI Bit Rate Register
TWBR selects the division factor for the bit rate generator. The bit rate generator is a frequency
divider which generates the SCL clock frequency in the Master modes. See
Unit” on page 215
The TWCR is used to control the operation of the TWI. It is used to enable the TWI, to initiate a
Master access by applying a START condition to the bus, to generate a Receiver acknowledge,
to generate a stop condition, and to control halting of the bus while the data to be written to the
bus are written to the TWDR. It also indicates a write collision if data is attempted written to
TWDR while the register is inaccessible.
Bit
(0xB8)
Read/Write
Initial Value
Bit
(0xBC)
Read/Write
Initial Value
SLA bits. Masters trying to output a one on SDA while another Master outputs a zero will lose
the arbitration. Masters losing arbitration in SLA will switch to Slave mode to check if they are
being addressed by the winning Master. If addressed, they will switch to SR or ST mode,
depending on the value of the READ/WRITE bit. If they are not being addressed, they will
switch to not addressed Slave mode or wait until the bus is free and transmit a new START
condition, depending on application software action.
START
TWBR7
TWINT
R/W
R/W
7
0
7
0
for calculating bit rates.
Address / General Call
Figure
Direction
received
Own
TWBR6
TWEA
R/W
R/W
Yes
Arbitration lost in SLA
6
0
6
0
SLA
21-21. Possible status values are given in circles.
Write
Read
TWBR5
TWSTA
R/W
R/W
No
5
0
5
0
TWSTO
TWBR4
R/W
R/W
4
0
4
0
68/78
38
B0
Arbitration lost in Data
TWBR3
TWWC
TWI bus will be released and not addressed slave mode will be entered
A START condition will be transmitted when the bus becomes free
Data byte will be received and NOT ACK will be returned
Data byte will be received and ACK will be returned
Last data byte will be transmitted and NOT ACK should be received
Data byte will be transmitted and ACK should be received
R/W
R
3
0
3
0
Data
TWBR2
TWEN
R/W
R/W
ATmega48/88/168
2
0
2
0
TWBR1
R/W
R
1
0
1
–
0
“Bit Rate Generator
TWBR0
TWIE
R/W
R/W
0
0
0
0
STOP
TWBR
TWCR
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