ATMEGA32U4-AUR Atmel, ATMEGA32U4-AUR Datasheet - Page 194

MCU AVR 16K FLASH 16MHZ 44TQFP

ATMEGA32U4-AUR

Manufacturer Part Number
ATMEGA32U4-AUR
Description
MCU AVR 16K FLASH 16MHZ 44TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheet

Specifications of ATMEGA32U4-AUR

Core Processor
AVR
Core Size
8-Bit
Speed
16MHz
Connectivity
I²C, SPI, UART/USART, USB
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
26
Program Memory Size
32KB (16K x 16)
Program Memory Type
FLASH
Eeprom Size
1K x 8
Ram Size
2.5K x 8
Voltage - Supply (vcc/vdd)
2.7 V ~ 5.5 V
Data Converters
A/D 12x10b
Oscillator Type
External
Operating Temperature
-40°C ~ 85°C
Package / Case
44-TQFP, 44-VQFP
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATMEGA32U4-AUR
Manufacturer:
Atmel
Quantity:
10 000
18.5.2
18.5.3
7766F–AVR–11/10
Sending Frames with 9 Data Bit
Transmitter Flags and Interrupts
If 9-bit characters are used (UCSZn = 7), the ninth bit must be written to the TXB8 bit in
UCSRnB before the low byte of the character is written to UDRn. The following code examples
show a transmit function that handles 9-bit characters. For the assembly code, the data to be
sent is assumed to be stored in registers R17:R16.
Notes:
The ninth bit can be used for indicating an address frame when using multi processor communi-
cation mode or for other protocol handling as for example synchronization.
The USART Transmitter has two flags that indicate its state: USART Data Register Empty
(UDREn) and Transmit Complete (TXCn). Both flags can be used for generating interrupts.
The Data Register Empty (UDREn) Flag indicates whether the transmit buffer is ready to receive
new data. This bit is set when the transmit buffer is empty, and cleared when the transmit buffer
contains data to be transmitted that has not yet been moved into the Shift Register. For compat-
ibility with future devices, always write this bit to zero when writing the UCSRnA Register.
Assembly Code Example
C Code Example
USART_Transmit:
void USART_Transmit( unsigned int data )
{
}
; Wait for empty transmit buffer
sbis UCSRnA,UDREn
rjmp USART_Transmit
; Copy 9th bit from r17 to TXB8
cbi
sbrc r17,0
sbi
; Put LSB data (r16) into buffer, sends the data
out
ret
/* Wait for empty transmit buffer */
while ( !( UCSRnA & (1<<UDREn))) )
/* Copy 9th bit to TXB8 */
UCSRnB &= ~(1<<TXB8);
if ( data & 0x0100 )
/* Put data into buffer, sends the data */
UDRn = data;
1. These transmit functions are written to be general functions. They can be optimized if the con-
2. See “Code Examples” on page 8.
UCSRnB |= (1<<TXB8);
tents of the UCSRnB is static. For example, only the TXB8 bit of the UCSRnB Register is used
after initialization.
UCSRnB,TXB8
UCSRnB,TXB8
UDRn,r16
;
(1)(2)
(1)(2)
ATmega16/32U4
194

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