ATtiny2313A Atmel Corporation, ATtiny2313A Datasheet - Page 126

• Manufacturer Part Number: ATtiny2313A
• Manufacturer: Atmel Corporation

Specifications of ATtiny2313A

• Flash (kbytes): 2 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 18
• Ext Interrupts: 18
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 0.12
• Eeprom (bytes): 128
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

14.6
126
Data Transmission – The USART Transmitter
ATtiny2313A/4313
The following simple USART initialization code examples show one assembly and one C func-
tion that are equal in functionality. The examples assume asynchronous operation using polling
(no interrupts enabled) and a fixed frame format. The baud rate is given as a function parameter.
For the assembly code, the baud rate parameter is assumed to be stored in the r17:r16
Registers.
Note:
More advanced initialization routines can be made that include frame format as parameters, dis-
able interrupts and so on. However, many applications use a fixed setting of the baud and
control registers, and for these types of applications the initialization code can be placed directly
in the main routine, or be combined with initialization code for other I/O modules.
The USART Transmitter is enabled by setting the Transmit Enable (TXEN) bit in the UCSRB
Register. When the Transmitter is enabled, the normal port operation of the TxD pin is overrid-
den by the USART and given the function as the Transmitter’s serial output. The baud rate,
mode of operation and frame format must be set up once before doing any transmissions. If syn-
chronous operation is used, the clock on the XCK pin will be overridden and used as
transmission clock.
Assembly Code Example
C Code Example
USART_Init:
void USART_Init( unsigned int baud )
{
}
; Set baud rate
out
out
; Enable receiver and transmitter
ldi
out
; Set frame format: 8data, 2stop bit
ldi
out
ret
/* Set baud rate */
UBRRH = (unsigned char)(baud>>8);
UBRRL = (unsigned char)baud;
/* Enable receiver and transmitter */
UCSRB = (1<<RXEN)|(1<<TXEN);
/* Set frame format: 8data, 2stop bit */
UCSRC = (1<<USBS)|(3<<UCSZ0);
1. See “Code Examples” on page 7.
UBRRH, r17
UBRRL, r16
r16, (1<<RXEN)|(1<<TXEN)
UCSRB,r16
r16, (1<<USBS)|(3<<UCSZ0)
UCSRC,r16
(1)
(1)
8246B–AVR–09/11