ATMEGA16-16MQ Atmel, ATMEGA16-16MQ Datasheet - Page 196

MCU AVR 16K FLASH 16MHZ 44-QFN

ATMEGA16-16MQ

Manufacturer Part Number
ATMEGA16-16MQ
Description
MCU AVR 16K FLASH 16MHZ 44-QFN
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheet

Specifications of ATMEGA16-16MQ

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
16KB (8K x 16)
Program Memory Type
FLASH
Eeprom Size
512 x 8
Ram Size
1K 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
44-VQFN Exposed Pad
Processor Series
ATMEGA16x
Core
AVR8
Data Bus Width
8 bit
Data Ram Size
1 KB
Mounting Style
SMD/SMT
3rd Party Development Tools
EWAVR, EWAVR-BL
Development Tools By Supplier
ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
For Use With
ATSTK600-TQFP44 - STK600 SOCKET/ADAPTER 44-TQFPATSTK500 - PROGRAMMER AVR STARTER KIT
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
2466T–AVR–07/10
The upper seven bits are the address to which the Two-wire Serial Interface will respond when
addressed by a Master. If the LSB is set, the TWI will respond to the general call address ($00),
otherwise it will ignore the general call address.
TWEN must be written to one to enable the TWI. The TWEA bit must be written to one to enable
the acknowledgement of the device’s own Slave address or the general call address. TWSTA
and TWSTO must be written to zero.
When TWAR and TWCR have been initialized, the TWI waits until it is addressed by its own
Slave address (or the general call address if enabled) followed by the data direction bit. If the
direction bit is “1” (read), the TWI will operate in ST mode, otherwise SR mode is entered. After
its own Slave address and the write bit have been received, the TWINT Flag is set and a valid
status code can be read from TWSR. The status code is used to determine the appropriate soft-
ware action. The appropriate action to be taken for each status code is detailed in
Slave Transmitter mode may also be entered if arbitration is lost while the TWI is in the Master
mode (see state $B0).
If the TWEA bit is written to zero during a transfer, the TWI will transmit the last byte of the trans-
fer. State $C0 or state $C8 will be entered, depending on whether the Master Receiver transmits
a NACK or ACK after the final byte. The TWI is switched to the not addressed Slave mode, and
will ignore the Master if it continues the transfer. Thus the Master Receiver receives all “1” as
serial data. State $C8 is entered if the Master demands additional data bytes (by transmitting
ACK), even though the Slave has transmitted the last byte (TWEA zero and expecting NACK
from the Master).
While TWEA is zero, the TWI does not respond to its own Slave address. However, the Two-
wire Serial Bus is still monitored and address recognition may resume at any time by setting
TWEA. This implies that the TWEA bit may be used to temporarily isolate the TWI from the Two-
wire Serial Bus.
In all sleep modes other than Idle mode, the clock system to the TWI is turned off. If the TWEA
bit is set, the interface can still acknowledge its own Slave address or the general call address
by using the Two-wire Serial Bus clock as a clock source. The part will then wake up from sleep
and the TWI will hold the SCL clock will low during the wake up and until the TWINT Flag is
cleared (by writing it to one). Further data transmission will be carried out as normal, with the
AVR clocks running as normal. Observe that if the AVR is set up with a long start-up time, the
SCL line may be held low for a long time, blocking other data transmissions.
Note that the Two-wire Serial Interface Data Register – TWDR does not reflect the last byte
present on the bus when waking up from these sleep modes.
TWCR
Value
TWINT
0
TWEA
1
TWSTA
0
TWSTO
0
TWWC
0
TWEN
1
ATmega16(L)
0
TWIE
Table
X
77. The
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