ATMEGA32A-AU Atmel, ATMEGA32A-AU Datasheet - Page 203
![MCU AVR 32K FLASH 16MHZ 44-TQFP](/photos/6/70/67042/313-44-tqfp_sml.jpg)
ATMEGA32A-AU
Manufacturer Part Number
ATMEGA32A-AU
Description
MCU AVR 32K FLASH 16MHZ 44-TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Specifications of ATMEGA32A-AU
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
32KB (16K x 16)
Program Memory Type
FLASH
Eeprom Size
1K x 8
Ram Size
2K 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
44-TQFP, 44-VQFP
Processor Series
ATMEGA32x
Core
AVR8
Data Bus Width
8 bit
Data Ram Size
2 KB
Interface Type
2-Wire/SPI/USART
Maximum Clock Frequency
16 MHz
Number Of Programmable I/os
32
Number Of Timers
3
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
3rd Party Development Tools
EWAVR, EWAVR-BL
Development Tools By Supplier
ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
Minimum Operating Temperature
- 40 C
On-chip Adc
8-ch x 10-bit
Data Rom Size
1024 B
Height
1 mm
Length
10 mm
Supply Voltage (max)
5.5 V
Supply Voltage (min)
2.7 V
Width
10 mm
Controller Family/series
AVR MEGA
No. Of I/o's
32
Eeprom Memory Size
1KB
Ram Memory Size
2KB
Cpu Speed
16MHz
Rohs Compliant
Yes
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
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ATMEGA32A-AU
Manufacturer:
ATMEL
Quantity:
5 600
Part Number:
ATMEGA32A-AU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Company:
Part Number:
ATMEGA32A-AUR
Manufacturer:
SMD
Quantity:
5
20.9.2
8155C–AVR–02/11
TWCR – TWI Control Register
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 7 – TWINT: TWI Interrupt Flag
This bit is set by hardware when the TWI has finished its current job and expects application
software response. If the I-bit in SREG and TWIE in TWCR are set, the MCU will jump to the
TWI Interrupt Vector. While the TWINT Flag is set, the SCL low period is stretched.
The TWINT Flag must be cleared by software by writing a logic one to it. Note that this flag is not
automatically cleared by hardware when executing the interrupt routine. Also note that clearing
this flag starts the operation of the TWI, so all accesses to the TWI Address Register (TWAR),
TWI Status Register (TWSR), and TWI Data Register (TWDR) must be complete before clearing
this flag.
• Bit 6 – TWEA: TWI Enable Acknowledge Bit
The TWEA bit controls the generation of the acknowledge pulse. If the TWEA bit is written to
one, the ACK pulse is generated on the TWI bus if the following conditions are met:
By writing the TWEA bit to zero, the device can be virtually disconnected from the Two-wire
Serial Bus temporarily. Address recognition can then be resumed by writing the TWEA bit to one
again.
• Bit 5 – TWSTA: TWI START Condition Bit
The application writes the TWSTA bit to one when it desires to become a master on the Two-
wire Serial Bus. The TWI hardware checks if the bus is available, and generates a START con-
dition on the bus if it is free. However, if the bus is not free, the TWI waits until a STOP condition
is detected, and then generates a new START condition to claim the bus Master status. TWSTA
must be cleared by software when the START condition has been transmitted.
• Bit 4 – TWSTO: TWI STOP Condition Bit
Writing the TWSTO bit to one in Master mode will generate a STOP condition on the Two-wire
Serial Bus. When the STOP condition is executed on the bus, the TWSTO bit is cleared auto-
matically. In slave mode, setting the TWSTO bit can be used to recover from an error condition.
This will not generate a STOP condition, but the TWI returns to a well-defined unaddressed
slave mode and releases the SCL and SDA lines to a high impedance state.
• Bit 3 – TWWC: TWI Write Collision Flag
The TWWC bit is set when attempting to write to the TWI Data Register – TWDR when TWINT is
low. This flag is cleared by writing the TWDR Register when TWINT is high.
Bit
Read/Write
Initial Value
1. The device’s own slave address has been received.
2. A general call has been received, while the TWGCE bit in the TWAR is set.
3. A data byte has been received in Master Receiver or Slave Receiver mode.
TWINT
R/W
7
0
TWEA
R/W
6
0
TWSTA
R/W
5
0
TWSTO
R/W
4
0
TWWC
R
3
0
TWEN
R/W
2
0
R
1
–
0
ATmega32A
TWIE
R/W
0
0
TWCR
203